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2
ENVIRONMENTAL
PROTECTION
AGENCY
40
CFR
Parts
9,
141,
and
142
[
OW­
2002­
0043EPA­
HQ­
OW­
2002­
0043;
FRL­
FRL­
XXXX­
X]

RIN
2040­
AD38
National
Primary
Drinking
Water
Regulations:
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
AGENCY:
Environmental
Protection
Agency
(
EPA).

ACTION:
Final
rule.

SUMMARY:
The
Environmental
Protection
Agency
(
EPA)
is
promulgating
today's
final
rule,

the
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
(
DBPR),
to
provide
for
increased
protection
against
the
potential
risks
for
cancer
and
reproductive
and
developmental
health
effects
associated
with
disinfection
byproducts
(
DBPs).
The
final
Stage
2
DBPR
contains
maximum
contaminant
level
goals
(
MCLGs)
for
chloroform,
monochloroacetic
acid
(
MCAA)
and
trichloroacetic
acid
(
TCAA);
National
Primary
Drinking
Water
Regulations
(
NPDWRs),
which
consist
of
maximum
contaminant
levels
(
MCLs)
and
monitoring,
reporting,
and
public
notification
requirements
for
total
trihalomethanes
(
TTHM
­
a
sum
of
chloroform,
bromodichloromethane,

dibromochloromethane,
and
bromoform)
and
haloacetic
acids
(
HAA5
­
a
sum
of
mono­,
di­,
and
trichloroacetic
acids
and
mono­
and
dibromoacetic
acids);
and
revisions
to
the
reduced
monitoring
requirements
for
bromate.
This
document
also
specifies
the
best
available
technologies
(
BATs)

for
the
final
MCLs.
EPA
is
also
approving
additional
analytical
methods
for
the
determination
of
disinfectants
and
DBPs
in
drinking
water.
EPA
believes
the
Stage
2
DBPR
will
reduce
the
3
potential
risks
of
cancer
and
reproductive
and
developmental
health
effects
associated
with
disinfection
byproducts
(
DBPs)
by
reducing
peak
and
average
levels
of
DBPs
in
drinking
water
supplies.

The
Stage
2
DBPR
applies
to
public
water
systems
(
PWSs)
that
are
community
water
systems
(
CWSs)
or
nontransient
noncommunity
water
systems
(
NTNCWs)
that
add
a
primary
or
residual
disinfectant
other
than
ultraviolet
light
or
deliver
water
that
has
been
treated
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
light.

This
rule
also
makes
minor
corrections
to
drinking
water
regulations,
specifically
the
Public
Notification
tables.
New
endnotes
were
added
to
these
tables
in
recent
rulemakings;

however,
the
corresponding
footnote
numbering
in
the
tables
was
not
changed.
In
addition,
this
rule
makes
a
minor
correction
to
the
Stage
1
Disinfectants
and
Disinfection
Byproducts
Rule
by
replacing
a
sentence
that
was
inadvertently
removed.

DATES:
This
final
rule
is
effective
on
[
INSERT
DATE
60
DAYS
AFTER
PUBLICATION
IN
THE
FEDERAL
REGISTER],
except
for
the
amendment
to
§
141.132
(
b)(
1)(
iv)
which
is
effective
on
[
INSERT
DATE
30
DAYS
AFTER.
For
judicial
review
purposes,
this
final
rule
is
promulgated
as
[
INSERT
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER].
The
incorporation
by
reference
of
certain
publications
listed
in
the
rule
is
approved
by
the
Director
of
the
Federal
Register
as
of
[
INSERT
DATE
60
DAYS
AFTER
PUBLICATION
IN
THE
FEDERAL
REGISTER].
For
judicial
review
purposes,
this
final
rule
is
promulgated
as
of
1
p.
m.,

Eastern
time
on
[
INSERT
DATE
14
DAYS
AFTER
PUBLICATION
IN
THE
FEDERAL
REGISTER],
as
provided
in
40
Code
of
Federal
Regulations
(
CFR)
23.7.

ADDRESSES:
4
ADDRESSES:
EPA
has
established
a
docket
for
this
action
under
Docket
ID
No.
OW­
2002­

0043EPA­
HQ­
OW­­
2002­
0043.
All
documents
in
the
docket
are
listed
inon
the
EDOCKET
index
at
http://
wwwwww.
eparegulations.
gov/
edocketgov
web
site.
Although
listed
in
the
index,
some
information
is
not
publicly
available,
ie.
eg.,
CBI
or
other
information
whose
disclosure
is
restricted
by
statute.
Certain
other
material,
such
as
copyrighted
material,
is
not
placed
on
the
Internet
and
will
be
publicly
available
only
in
hard
copy
form.
Publicly
available
docket
materials
are
available
either
electronically
in
EDOCKETthrough
www.
regulations.
gov
or
in
hard
copy
at
the
Water
Docket,
EPA/
DC,
EPA
West,
Room
B102,
1301
Constitution
Ave.,

NW,
Washington,
DC.
The
Public
Reading
Room
is
open
from
810:
3000
a.
m.
to
4:
3000
p.
m.,

Monday
through
Friday,
excluding
legal
holidays.
The
telephone
number
for
the
Public
Reading
Room
is
(
202)
566­
1744,
and
the
telephone
number
for
the
Water
Docket
is
(
202)
566­
2426.

FOR
FURTHER
INFORMATION
CONTACT:
For
technical
inquiries,
contact
Tom
Grubbs,

Standards
and
Risk
Management
Division,
Office
of
Ground
Water
and
Drinking
Water
(
MC
4607M),
Environmental
Protection
Agency,
1200
Pennsylvania
Ave.,
NW.,
Washington,
DC
20460;
telephone
number:
(
202)
564­
5262;
fax
number:
(
202)
564­
3767;
e­
mail
address:

grubbs.
thomas@
epa.
gov.
For
general
information,
contact
the
Safe
Drinking
Water
Hotline,

Telephone
(
800)
426­
4791.
The
Safe
Drinking
Water
Hotline
is
open
Monday
through
Friday,

excluding
legal
holidays,
from
910:
00
a.
m.
to
4:
3000
p.
m.
Eastern
Time.

SUPPLEMENTARY
INFORMATION:

I.
General
Information
A.
Does
This
Action
Apply
to
Me?

Entities
potentially
regulated
by
the
Stage
2
DBPR
are
community
and
nontransient
5
noncommunity
water
systems
that
add
a
primary
or
residual
disinfectant
other
than
ultraviolet
light
or
deliver
water
that
has
been
treated
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
light.
Regulated
categories
and
entities
are
identified
in
the
following
chart.
6
Category
Examples
of
Regulated
Entities
Industry
Community
and
nontransient
noncommunity
water
systems
that
use
a
primary
or
residual
disinfectant
other
than
ultraviolet
light
or
deliver
water
that
has
been
treated
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
light.

State,
Local,
Tribal,
or
Federal
Governments
Community
and
nontransient
noncommunity
water
systems
that
use
a
primary
or
residual
disinfectant
other
than
ultraviolet
light
or
deliver
water
that
has
been
treated
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
light.

This
table
is
not
intended
to
be
exhaustive,
but
rather
provides
a
guide
for
readers
regarding
entities
likely
to
be
regulated
by
this
action.
This
table
lists
the
types
of
entities
that
EPA
is
now
aware
could
potentially
be
regulated
by
this
action.
Other
types
of
entities
not
listed
in
the
table
could
also
be
regulated.
To
determine
whether
your
facility
is
regulated
by
this
action,

you
should
carefully
examine
the
definition
of
"
public
water
system"
in
§
141.2
and
the
section
entitled
"
coverage"
(
§
141.3)
in
Title
40
of
the
Code
of
Federal
Regulations
and
applicability
criteria
in
§
141.600
and
141.620
of
today's
proposal.
If
you
have
questions
regarding
the
applicability
of
this
action
to
a
particular
entity,
contact
the
person
listed
in
the
preceding
"
FOR
FURTHER
INFORMATION
CONTACT"
section.

B.
How
Can
I
Get
Copies
of
This
Document
and
Other
Related
Information?

See
the
"
ADDRESSES"
section
for
information
on
how
to
receive
a
copy
of
this
document
and
related
information.

Regional
contacts:
7
I.
Kevin
Reilly
Water
Supply
Section
JFK
Federal
Bldg.,
Room
203
Boston,
MA
02203
(
617)
565­
3616
II.
Michael
Lowy
Water
Supply
Section
290
Broadway
24th
Floor
New
York,
NY
10007­
1866
(
212)
637­
3830
III.
Jason
Gambatese
Drinking
Water
Section
(
3WM41)
1650
Arch
Street
Philadelphia,
PA
19103­
2029
(
215)
814­
5759
IV.
Robert
Burns
Drinking
Water
Section
61
Forsyth
Street
SW
Atlanta,
GA
30303
(
404)
562­
9456
V.
Miguel
Del
Toral
Water
Supply
Section
77
W.
Jackson
Blvd.
Chicago,
IL
60604
(
312)
886­
5253
VI.
Blake
L.
Atkins
Drinking
Water
Section
1445
Ross
Avenue
Dallas,
TX
75202
(
214)
665­
2297
VII.
Stan
Calow
or
DougDouglas
J.
Brune
Drinking
Water/
Ground
Water
Management
Branch
726
Minnesota
Ave.
901
North
5th
Street
Kansas
City,
KS
66101
(
913800)
551­
7410
(
Calow)
(
913)
551­
7178233­
0425
8
VIII.
Bob
Clement
Public
Water
Supply
Section
(
8P2­
W­
MS)
999
18th
Street,
Suite
500
Denver,
CO
80202­
2466
(
303)
312­
6653
IX.
Bruce
Macler
Water
Supply
Section
75
Hawthorne
Street
San
Francisco,
CA
94105
(
415)
972­
3569
X.
Wendy
Marshall
Drinking
Water
Unit
1200
Sixth
Avenue
(
OW­
136)
Seattle,
WA
98101
(
206)
553­
1890
Abbreviations
used
in
this
Document
AIPC
All
Indian
Pueblo
Council
ALT
Alanine
aminotransferase
ASDWA
Association
of
State
Drinking
Water
Administrators
AST
Aspartate
aminotransferase
ASTM
American
Society
for
Testing
and
Materials
AWWA
American
Water
Works
Association
AwwaRF
American
Water
Works
Association
Research
Foundation
BAT
Best
available
technology
BCAA
Bromochloroacetic
acid
BDCM
Bromodichloromethane
CMA
Chemicals
Manufacturer
AssociationCDBG
Community
Development
Block
Grant
CWS
Community
water
system
DBAA
Dibromoacetic
acid
DBCM
Dibromochloromethane
DBP
Disinfection
byproduct
DBPR
Disinfectants
and
Disinfection
Byproducts
Rule
DCAA
Dichloroacetic
acid
DOC
Dissolved
organic
carbon
EA
Economic
analysis
EC
Enhanced
coagulation
EDA
Ethylenediamine
9
EPA
United
States
Environmental
Protection
Agency
ESWTR
Enhanced
Surface
Water
Treatment
Rule
FACA
Federal
Advisory
Committee
Act
FBRR
Filter
Backwash
Recycling
Rule
GAC
Granular
activated
carbon
GC/
ECD
Gas
chromatography
using
electron
capture
detection
GWR
Ground
Water
Rule
GWUDI
Ground
water
under
the
direct
influence
of
surface
water
HAA5
Haloacetic
acids
(
five)
(
sum
of
monochloroacetic
acid,
dichloroacetic
acid,
trichloroacetic
acid,
monobromoacetic
acid,
and
dibromoacetic
acid)
HAN
Haloacetonitriles
(
trichloroacetonitrile,
dichloroacetonitrile,
bromochloroacetonitrile,
and
dibromoacetonitrile)
IC
Ion
chromatograph
IC/
ICP­
MS
Ion
chromatograph 
coupled
to
an
inductively
coupled
plasma
mass
spectrometer
IDSE
Initial
distribution
system
evaluation
ILSI
International
Life
Sciences
Institute
IESWTR
Interim
Enhanced
Surface
Water
Treatment
Rule
IPCS
International
Programme
on
Chemical
Safety
IRIS
Integrated
Risk
Information
System
(
EPA)
LH
Luteinizing
hormone
LOAEL
Lowest
observed
adverse
effect
level
LRAA
Locational
running
annual
average
LT1ESTWR
Long
Term
1
Enhanced
Surface
Water
Treatment
Rule
LT2ESTWR
Long
Term
2
Enhanced
Surface
Water
Treatment
Rule
MBAA
Monobromoacetic
acid
MCAA
Monochloroacetic
acid
MCL
Maximum
contaminant
level
MCLG
Maximum
contaminant
level
goal
M­
DBP
Microbial
and
disinfection
byproducts
mg/
L
Milligram
per
liter
MRL
Minimum
reporting
level
MRDL
Maximum
residual
disinfectant
level
MRDLG
Maximum
residual
disinfectant
level
goal
MTBE
Methyl
tertiary
butyl
ether
NATICH
National
Air
Toxics
Information
Clearinghouse
NDIR
Nondispersive
infrared
detection
NDMA
N­
nitrosodimethylamine
NDWAC
National
Drinking
Water
Advisory
Council
NF
Nanofiltration
NOAEL
No
Observed
Adverse
Effect
Level
NODA
Notice
of
data
availability
NPDWR
National
primary
drinking
water
regulation
NRWA
National
Rural
Water
Association
NTNCWS
Nontransient
noncommunity
water
system
10
NTP
National
Toxicology
Program
NTTAA
National
Technology
Transfer
and
Advancement
Act
ODA
o­
dianisidine
dihydrochloride
OMB
Office
of
Management
and
Budget
OSTP
Office
of
Science
and
Technology
Policy
PAR
Population
attributable
risk
PE
Performance
evaluation
PWS
Public
water
system
QC
Quality
control
RAA
Running
annual
average
RFA
Regulatory
Flexibility
Act
RfD
Reference
dose
RSC
Relative
source
contribution
RSDRUS
Relative
standard
deviationRural
Utility
Service
SAB
Science
Advisory
Board
SAC
Selective
anion
concentration
SBAR
Small
Business
Advisory
Review
SBREFA
Small
Business
Regulatory
Enforcement
Fairness
Act
SDWA
Safe
Drinking
Water
Act,
or
the
"
Act,"
as
amended
in
1996
SER
Small
Entity
Representative
SGA
Small
for
gestational
age
SMP
Standard
Monitoring
Program
SRR
Standardized
rate
ratio
SUVA
Specific
ultraviolet
absorbance
SWAT
Surface
Water
Analytical
Tool
SWTR
Surface
Water
Treatment
Rule
TC
Total
coliforms
TCAA
Trichloroacetic
acid
TCR
Total
Coliform
Rule
THM
Trihalomethane
TOC
Total
organic
carbon
TTHM
Total
trihalomethanes
(
sum
of
four
THMs:
chloroform,
bromodichloromethane,
dibromochloromethane,
and
bromoform)
TWG
Technical
work
group
UMRA
Unfunded
Mandates
Reform
Act
UV
254
Ultraviolet
absorption
at
254
nm
VSL
Value
of
Statistical
Life
WTP
Willingness
To
Pay
Table
of
Contents
I.
General
Information
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
3
A.
Does
This
Action
Apply
to
Me?
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
3
11
B.
How
Can
I
Get
Copies
of
This
Document
and
Other
Related
Information?
.
.
.
.
.
.
.
4
II.
Summary
of
the
Final
Rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
13
A.
Why
is
EPA
Promulgating
the
Stage
2
DBPR?
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
13
B.
What
Does
the
Stage
2
DBPR
Require?
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
15
1.
Initial
Distribution
System
Evaluation
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
16
2.
Compliance
and
monitoring
requirements
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
17
3.
Operational
Evaluation
Levels
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
18
4.
Consecutive
systems
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
.
18
C.
Correction
of
§
141.132
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
19
III.
Background
.
.
.
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.
.
.
20
A.
Statutory
Requirements
and
Legal
Authority
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
20
B.
What
is
the
Regulatory
History
of
the
Stage
2
DBPR
and
How
Were
Stakeholders
Involved?
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
.
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.
.
.
.
.
.
21
1.
Total
Trihalomethanes
Rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
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.
.
.
.
.
.
.
.
.
22
2.
Stage
1
Disinfectants
and
Disinfection
Byproducts
Rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
22
3.
Stakeholder
involvement
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
23
a.
Federal
Advisory
Committee
process
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
23
b.
Other
outreach
processes
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
25
C.
Public
Health
Concerns
to
be
Addressed
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
26
1.
What
are
DBPs?
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
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.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
26
2.
DBP
Health
Effects
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
27
a.
Cancer
health
effects
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
29
i.
Epidemiology
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
30
ii.
Toxicology
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
37
b.
Reproductive
and
developmental
health
effects
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
39
i.
Epidemiology
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
39
ii.
Toxicology
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
51
c.
Conclusions
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
52
D.
DBP
Occurrence
and
DBP
Control
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
53
1.
Occurrence
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
53
2.
Treatment
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
55
E.
Conclusions
for
Regulatory
Action
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
56
IV.
Explanation
of
Today's
Action
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
56
A.
MCLGs
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
56
1.
Chloroform
MCLG
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
57
a.
Today's
rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
57
b.
Background
and
analysis
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
57
c.
Summary
of
major
comments
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
58
2.
HAA
MCLGs:
TCAA
and
MCAA
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
59
a.
Today's
rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
59
b.
Background
and
analysis
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
59
12
c.
Summary
of
major
comments
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
64
B.
Consecutive
Systems
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
64
1.
Today's
Rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
65
2.
Background
and
analysis
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
66
3.
Summary
of
major
comments
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
67
C.
LRAA
MCLs
for
TTHM
and
HAA5
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
69
1.
Today's
rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
69
2.
Background
and
analysis
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
69
3.
Summary
of
major
comments
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
74
D.
BAT
for
TTHM
and
HAA5
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
76
1.
Today's
rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
76
2.
Background
and
analysis
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
77
3.
Summary
of
major
comments
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
81
E.
Compliance
Schedules
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
82
1.
Today's
rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
82
2.
Background
and
analysis
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
86
3.
Summary
of
major
comments
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
90
F.
Initial
Distribution
System
Evaluation
(
IDSE)
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
94
1.
Today's
rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
94
a.
Applicability
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
95
b.
Data
collection
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
95
i.
Standard
monitoring
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
95
ii.
System
specific
study
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
95
iii.
40/
30
certification
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
96
c.
Implementation
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
97
2.
Background
and
analysis
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
102
a.
Standard
monitoring
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
103
b.
Very
small
system
waivers
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
104
c.
40/
30
certifications
.
.
.
.
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105
d.
System­
specificSystem
specific
studies
.
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106
e.
Distribution
System
Schematics
3.
Summary
of
major
comments
.
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109
G.
Monitoring
Requirements
and
Compliance
Determination
for
TTHM
and
HAA5
MCLs
.
.
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110
1.
Today's
Rule
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111
a.
IDSE
Monitoring
.
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111
b.
Routine
Stage
2
Compliance
Monitoring
.
.
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.
113
i.
Reduced
monitoring
.
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115
ii.
Compliance
determination
.
.
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.
118
2.
Background
and
Analysis
.
.
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.
118
3.
Summary
of
Major
Comments
.
.
.
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.
123
H.
Operational
Evaluation
Requirements
initiated
by
TTHM
and
HAA5
Levels
.
.
.
.
.
126
1.
Today's
rule
.
.
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127
2.
Background
and
analysis
.
.
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.
128
13
3.
Summary
of
major
comments
.
.
.
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130
I.
MCL,
BAT,
and
Monitoring
for
Bromate
.
.
.
.
.
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.
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.
133
1.
Today's
rule
.
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.
133
2.
Background
and
analysis
.
.
.
.
.
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.
134
a.
Bromate
MCL
.
.
.
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.
.
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.
.
134
b.
Criterion
for
reduced
bromate
monitoring
.
.
.
.
.
.
.
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.
.
134
3.
Summary
of
major
comments
.
.
.
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.
135
J.
Public
Notice
Requirements
.
.
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.
136
1.
Today's
rule
.
.
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.
136
2.
Background
and
analysis
.
.
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.
136
3.
Summary
of
major
comments
.
.
.
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136
K.
Variances
and
Exemptions
.
.
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.
138
L.
Requirements
for
Systems
to
Use
Qualified
Operators
.
.
.
.
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.
138
M.
System
Reporting
and
Recordkeeping
Requirements
.
.
.
.
.
.
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.
.
139
1.
Today's
rule
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.
139
2.
Summary
of
major
comments
.
.
.
.
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.
.
140
N.
Approval
of
Additional
Analytical
Methods
.
.
.
.
.
.
.
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.
.
140
1.
Today's
Rule
.
.
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.
140
2.
Background
and
Analysis
.
.
.
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.
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.
140
Oa.
Laboratory
Certification
and
Approval
.
.
.
.
.
.
.
.
.
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.
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.
.
.
.
.
.
141
1.
PE
acceptance
criteria
.
.
.
.
.
.
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.
.
.
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.
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.
141
a.
Today's
rule
.
.
.
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.
.
.
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.
.
141
b.
Background
and
analysis
.
.
.
.
.
.
.
.
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.
.
.
.
.
.
.
.
.
.
.
.
.
142
cVariances
b.
Affordable
Treatment
Technologies
for
Small
Systems
c.
Exemptions
3.
Summary
of
major
comments
.
.
.
.
.
.
.
.
.
.
.
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.
.
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.
.
142
2.
Minimum
reporting
limits
.
.
.
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.
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.
.
143
a.
Today's
rule
.
.
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.
.
.
.
.
143
b.
Background
and
analysis
.
.
.
.
.
.
.
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.
.
144
c
L.
Requirements
for
Systems
to
Use
Qualified
Operators
M.
System
Reporting
and
Recordkeeping
Requirements
1.
Today's
rule
2.
Summary
of
major
comments
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
.
146
P.
Other
regulatory
changes
.
.
.
.
.
.
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.
.
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.
146
V.
State
Implementation
.
.
.
.
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.
.
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.
.
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.
146
A.
Today's
rule
.
.
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.
.
146
1.
State
Primacy
Requirements
for
Implementation
Flexibility
.
.
.
.
.
.
.
.
.
.
.
.
147
2.
State
recordkeeping
requirements
.
.
.
.
.
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.
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.
.
.
147
3.
State
reporting
requirements
.
.
.
.
.
.
.
.
.
.
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.
.
.
148
4.
Interim
primacy
.
.
.
.
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.
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.
148
5.
IDSE
implementation
.
.
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.
.
.
148
14
BN.
Approval
of
Additional
Analytical
Methods
1.
Today's
Rule
2.
Background
and
Analysis
.
.
.
.
.
.
.
.
.
.
.
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.
.
148
O.
Laboratory
Certification
and
Approval
1.
PE
acceptance
criteria
a.
Today's
rule
b.
Background
and
analysis
c.
Summary
of
major
comments
2.
Minimum
reporting
limits
a.
Today's
rule
b.
Background
and
analysis
c.
Summary
of
major
comments
P.
Other
regulatory
changes
V.
State
Implementation
A.
Today's
rule
1.
State
Primacy
Requirements
for
Implementation
Flexibility
2.
State
recordkeeping
requirements
3.
State
reporting
requirements
4.
Interim
primacy
5.
IDSE
implementation
B.
Background
and
Analysis
C.
Summary
of
Major
Comments
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
151
VI.
Economic
Analysis
.
.
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.
.
151
A.
Regulatory
Alternatives
Considered
.
.
.
.
.
.
.
.
.
.
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.
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.
.
.
.
.
.
.
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.
.
.
152
B.
Analyses
that
Support
Today's
Final
Rule
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
156
1.
Predicting
water
quality
and
treatment
changes
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
156
2.
Estimating
benefits
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
.
157
3.
Estimating
costs
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
.
.
.
.
.
160
4.
Comparing
regulatory
alternatives
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
161
C.
Benefits
of
the
Stage
2
DBPR
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
162
1.
Nonquantified
benefits
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
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.
.
.
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.
.
.
.
.
.
.
.
.
.
.
162
2.
Quantified
benefits
.
.
.
.
.
.
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163
3.
Timing
of
benefits
accrual
.
.
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.
166
D.
Costs
of
the
Stage
2
DBPR
.
.
.
.
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.
.
168
1.
Total
annualized
present
value
costs
.
.
.
.
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168
2.
PWS
costs
.
.
.
.
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.
171
a.
IDSE
costs
.
.
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.
171
b.
PWS
treatment
costs
.
.
.
.
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.
175
c.
Monitoring
costs
.
.
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178
3.
State/
Primacy
agency
costs
.
.
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180
4.
Non­
quantified
costs
.
.
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.
180
E.
Household
Costs
of
the
Stage
2
DBPR
.
.
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.
181
15
F.
Incremental
Costs
and
Benefits
of
the
Stage
2
DBPR
.
.
.
.
.
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.
182
G.
Benefits
From
the
Reduction
of
Co­
occurring
Contaminants
.
.
.
.
.
.
.
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.
.
184
H.
Potential
Risks
From
Other
Contaminants
.
.
.
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.
.
185
1.
Emerging
DBPs
.
.
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.
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185
2.
N­
nitrosamines
.
.
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.
186
3.
Other
DBPs
.
.
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.
.
187
I.
Effects
of
the
Contaminant
on
the
General
Population
and
Groups
within
the
General
Population
that
are
Identified
as
Likely
to
be
at
Greater
Risk
of
Adverse
Health
Effects
.
.
.
.
.
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.
.
.
187
J.
Uncertainties
in
the
Risk,
Benefit,
and
Cost
Estimates
for
the
Stage
2
DBPR
.
.
.
.
.
189
K.
Benefit/
Cost
Determination
for
the
Stage
2
DBPR
.
.
.
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.
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.
.
194
L.
Summary
of
Major
Comments
.
.
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.
.
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.
.
197
1.
Interpretation
of
health
effects
studies
.
.
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.
197
2.
Derivation
of
benefits
.
.
.
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.
199
3.
Use
of
SWAT
.
.
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.
201
5.
Unanticipated
risk
issues
.
.
.
.
.
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.
204
6.
Valuation
of
cancer
cases
avoided
.
.
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.
204
VII.
Statutory
and
Executive
Order
Reviews
.
.
.
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.
205
A.
Executive
Order
12866:
Regulatory
Planning
and
Review
.
.
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.
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.
205
B.
Paperwork
Reduction
Act
.
.
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.
206
C.
Regulatory
Flexibility
Act
.
.
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.
208
D.
Unfunded
Mandates
Reform
Act
.
.
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.
211
E.
Executive
Order
13132:
Federalism
.
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.
213
F.
Executive
Order
13175:
Consultation
and
Coordination
With
Indian
Tribal
Governments
.
.
.
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.
.
214
G.
Executive
order
13045:
Protection
of
Children
from
Environmental
Health
Risks
and
Safety
Risks
.
.
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.
.
215
H.
Executive
Order
13211:
Actions
Concerning
Regulations
That
Significantly
Affect
Energy
Supply,
Distribution,
or
Use
.
.
.
.
.
.
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.
216
I.
National
Technology
Transfer
and
Advancement
Act
.
.
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.
.
.
219
J.
Executive
Order
12898:
Federal
Actions
to
Address
Environmental
Justice
in
Minority
Populations
or
Low­
Income
Populations
.
.
.
.
.
.
.
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.
.
.
.
.
220
K.
Consultations
with
the
Science
Advisory
Board,
National
Drinking
Water
Advisory
Council,
and
the
Secretary
of
Health
and
Human
Services
.
.
.
.
.
.
.
.
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.
.
.
.
.
.
220
L.
Plain
Language
.
.
.
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.
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.
.
221
M
M.
Analysis
of
the
Likely
Effect
of
Compliance
with
the
Stage
2
DBPR
on
the
Technical,
Managerial,
and
Financial
Capacity
of
Public
Water
Systems
N.
Congressional
Review
Act
.
.
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.
221
VIII.
References
.
.
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.
222
16
II.
Summary
of
the
Final
Rule
A.
Why
is
EPA
Promulgating
the
Stage
2
DBPR?

The
Environmental
Protection
Agency
is
proposingfinalizing
the
Stage
2
Disinfectants
and
Disinfection
Byproduct
Rule
(
DBPR)
to
reduce
potential
cancer
risks
and
address
concerns
with
potential
reproductive
and
developmental
risks
from
DBPs.
The
Agency
is
committed
to
ensuring
that
all
public
water
systems
provide
clean
and
safe
drinking
water.
Disinfectants
are
an
essential
element
of
drinking
water
treatment
because
of
the
barrier
they
provide
against
harmful
waterborne
microbial
pathogens.
However,
disinfectants
react
with
naturally
occurring
organic
and
inorganic
matter
in
source
water
and
distribution
systems
to
form
disinfection
byproducts
(
DBPs)
that
may
pose
health
risks.
The
Stage
2
DBPR
is
designed
to
reduce
the
level
of
exposure
from
DBPs
without
undermining
the
control
of
microbial
pathogens.
The
Long
Term
2
Enhanced
Surface
Water
Treatment
Rule
(
LT2ESWTR)
is
being
finalized
and
implemented
simultaneously
with
the
Stage
2
DBPR
to
ensure
that
drinking
water
is
microbiologically
safe
at
the
limits
set
for
DBPs.

Congress
required
EPA
to
promulgate
the
Stage
2
DBPR
as
part
of
the
1996
Safe
Drinking
Water
Act
(
SDWA)
Amendments
(
section
1412(
b)(
2)(
C)).
The
Stage
2
DBPR
augments
the
Stage
1
DBPR
that
was
finalized
in
1998
(
63
FR
69390,
December
16,
1998)

(
USEPA
1998a).
The
goal
of
the
Stage
2
DBPR
is
to
target
the
highest
risk
systems
for
changes
beyond
those
required
for
Stage
1
DBPR.
Today's
rule
reflects
consensus
recommendations
from
the
Stage
2
Microbial/
Disinfection
Byproducts
(
M­
DBP)
Federal
Advisory
Committee
(
the
Advisory
Committee)
as
well
as
public
comments.

New
information
on
health
effects,
occurrence,
and
treatment
has
become
available
since
17
the
Stage
1
DBPR
that
supports
the
need
for
the
Stage
2
DBPR.
EPA
has
completed
a
more
extensive
analysis
of
health
effects,
particularly
reproductive
and
developmental
endpoints,

associated
with
DBPs
since
the
Stage
1
DBPR.
RSome
recent
studies
on
both
human
epidemiology
and
animal
toxicology
have
shown
possible
associations
between
chlorinated
drinking
water
and
reproductive
and
developmental
endpoints
such
as
spontaneous
abortion,

stillbirth,
neural
tube
and
other
birth
defects,
intrauterine
growth
retardation,
and
low
birth
weight.
While
results
of
these
studies
have
been
mixed,
EPA
believes
they
support
a
potential
hazard
concern.
New
epidemiology
and
toxicology
studies
evaluating
bladder,
colon,
and
rectal
cancers
have
also
increased
the
weight
of
evidence
linking
these
health
effects
to
DBP
exposure.

The
large
number
of
people
(
more
than
260
million
Americans)
exposed
to
DBPs
and
the
potential
cancer,
reproductive,
and
developmental
risks
have
played
a
significant
role
in
EPA's
decision
to
move
forward
with
regulatory
changes
that
target
lowering
DBP
exposures
beyond
the
requirements
of
the
Stage
1
DBPR.

While
the
Stage
1
DBPR
is
predicted
to
provide
a
major
reduction
in
DBP
exposure,

national
survey
data
suggest
that
some
customers
may
receive
drinking
water
with
elevated,
or
peak,
DBP
concentrations
even
when
their
distribution
systems
is
in
compliance
with
the
Stage
1
DBPR.
Some
of
these
peak
concentrations
are
substantially
greater
than
the
Stage
1
DBPR
maximum
contaminant
levels
(
MCLs)
and
some
customers
receive
these
elevated
levels
of
DBPs
on
a
consistent
basis.
The
new
survey
results
also
show
that
Stage
1
DBPR
monitoring
sites
may
not
be
representative
of
higher
DBP
concentrations
that
occur
in
distribution
systems.
In
addition,
new
studies
indicate
that
cost­
effective
technologies
including
ultraviolet
light
(
UV)
and
granular
activated
carbon
(
GAC)
may
be
very
effective
at
lowering
DBP
levels.
EPA's
analysis
of
18
this
new
occurrence
and
treatment
information
indicates
that
significant
public
health
benefits
may
be
achieved
through
further,
cost­
effective
reductions
of
DBPs
in
distribution
systems.

The
Stage
2
DBPR
presents
a
risk­
targeting
approach
to
reduce
risks
from
DBPs.
The
new
requirements
provide
for
more
consistent,
equitable
protection
from
DBPs
across
the
entire
distribution
system
and
the
reduction
of
DBP
peaks.
New
risk­
targeting
provisions
require
systems
to
first
identify
their
risk
level;
then,
only
those
systems
with
the
greatest
risk
will
need
to
make
operational
or
treatment
changes.
The
Stage
2
DBPR,
in
conjunction
with
the
LT2ESWTR,
will
help
public
water
systems
deliver
safer
water
to
Americans
with
the
benefits
of
disinfection
to
control
pathogens
and
with
fewer
risks
from
DBPs.

B.
What
Does
the
Stage
2
DBPR
Require?

The
risk­
targeting
components
of
the
Stage
2
DBPR
focus
the
greatest
amount
of
change
where
the
greatest
amount
of
risk
may
exist.
Therefore,
the
provisions
of
the
Stage
2
DBPR
focus
first
on
identifying
the
higher
risks
through
the
Initial
Distribution
System
Evaluation
(
IDSE).
The
rule
then
addresses
reducing
exposure
and
lowering
DBP
peaks
in
distribution
systems
by
using
a
new
method
to
determine
MCL
compliance
(
locational
running
annual
average
(
LRAA)),
defining
operational
evaluation
levels,
and
regulating
consecutive
systems.
This
section
briefly
describes
the
requirements
of
this
final
rule.
More
detailed
information
on
the
regulatory
requirements
for
this
rule
can
be
found
in
Section
IV.

1.
Initial
Distribution
System
Evaluation
The
first
provision,
designed
to
identify
higher
risk
systems,
is
the
Initial
Distribution
System
Evaluation
(
IDSE).
The
purpose
of
the
IDSE
is
to
identify
Stage
2
DBPR
compliance
19
monitoring
sites
that
represent
each
system's
highest
levels
of
DBPs.
Because
Stage
2
DBPR
compliance
will
be
determined
at
these
new
monitoring
sites,
only
those
systems
that
identify
elevated
concentrations
of
TTHM
and
HAA5
will
need
to
make
treatment
or
process
changes
to
bring
the
system
into
compliance
with
the
Stage
2
DBPR.
By
identifying
compliance
monitoring
sites
with
the
highest
concentrations
of
TTHM
and
HAA5
in
each
system's
distribution
system,

the
IDSE
will
offer
increased
assurance
that
MCLs
are
being
met
across
the
distribution
system
and
that
customers
are
receiving
more
equitable
public
health
protection.
Both
treatment
changes
and
awareness
of
TTHM
and
HAA5
levels
resulting
from
the
IDSE
will
allow
systems
to
better
control
for
distribution
system
peaks.

The
IDSE
is
designed
to
offer
flexibility
to
public
water
systems.
The
IDSE
requires
TTHM
and
HAA5
monitoring
for
one
year
on
a
regular
schedule
that
is
determined
by
source
water
type
and
system
size.
Alternatively,
systems
have
the
option
of
performing
a
site­
specific
study
based
on
historical
data,
water
distribution
system
models,
or
other
data;
and
waivers
are
available
under
certain
circumstances.
The
IDSE
requirements
are
discussed
in
Sections
IV.
E,

IV.
F.,
and
IV.
G
of
this
preamble
and
in
subpart
U
of
the
rule
language.

2.
Compliance
and
monitoring
requirements
As
in
Stage
1,
the
Stage
2
DBPR
focuses
on
monitoring
for
and
reducing
concentrations
of
two
classes
of
DBPs:
total
trihalomethanes
(
TTHM)
and
haloacetic
acids
(
HAA5).
These
two
groups
of
DBPs
act
as
indicators
for
the
various
byproducts
that
are
present
in
water
disinfected
with
chlorine
or
chloramine.
This
means
that
concentrations
of
TTHM
and
HAA5
are
monitored
for
compliance,
but
their
presence
in
drinking
water
is
representative
of
many
other
chlorination
DBPs
that
may
also
occur
in
the
water;
thus,
a
reduction
in
TTHM
and
HAA5
generally
indicates
20
an
overall
reduction
of
DBPs.

The
second
provision
of
the
Stage
2
DBPR
is
designed
to
address
spatial
variations
in
DBP
exposure
through
a
new
compliance
calculation
(
referred
to
as
locational
running
annual
average)
for
TTHM
and
HAA5
MCLs.
The
MCL
values
remain
the
same
as
in
the
Stage
1.
The
Stage
1
DBPR
running
annual
average
(
RAA)
calculation
allowed
some
locations
within
a
distribution
system
to
have
higher
DBP
annual
averages
than
others
as
long
as
the
system­
wide
average
was
below
the
MCL.
The
Stage
2
DBPR
bases
compliance
on
a
locational
running
annual
average
(
LRAA)
calculation,
where
the
annual
average
at
each
sampling
location
in
the
distribution
system
will
be
used
to
determine
compliance
with
the
MCLs
of
0.080
mg/
L
and
0.060
mg/
L
for
TTHM
and
HAA5,
respectively.
The
LRAA
will
reduce
exposures
to
high
DBP
concentrations
by
ensuring
that
each
monitoring
site
is
in
compliance
with
the
MCLs
as
an
annual
average,
while
providing
all
customers
drinking
water
that
more
consistently
meets
the
MCLs.
A
more
detailed
discussion
of
Stage
2
DBPR
MCL
requirements
can
be
found
in
Sections
IV.
C,

IV.
E,
and
IV.
G
of
this
preamble
and
in
§
141.64(
b)(
2)
and
(
3)
and
subpart
V
of
the
rule
language.

The
number
of
compliance
monitoring
sites
is
based
on
the
population
served
and
the
source
water
type.
EPA
believes
that
population­
based
monitoring
provides
better
risk­
targeting
and
is
easier
to
implement.
Section
IV.
G
describes
population­
based
monitoring
and
how
it
affects
systems
complying
with
this
rule.

The
Stage
2
DBPR
includes
new
MCLGs
for
chloroform,
monochloroacetic
acid,
and
trichloroacetic
acid,
but
these
new
MCLGs
do
not
affect
the
MCLs
for
TTHM
or
HAA5.

3.
Operational
Evaluation
Levels
The
IDSE
and
LRAA
calculation
will
lead
to
lower
DBP
concentrations
overall
and
21
reduce
short
term
exposures
to
high
DBP
concentrations
in
certain
areas,
but
this
strengthened
approach
to
regulating
DBPs
will
still
allow
individual
DBP
samples
above
the
MCL
even
when
systems
are
in
compliance
with
the
Stage
2
DBPR.
Today's
rule
requires
systems
that
exceed
operational
evaluation
levels
(
referred
to
as
significant
excursions
in
the
proposed
rule)
to
evaluate
system
operational
practices
and
identify
opportunities
to
reduce
DBP
concentrations
in
the
distribution
system.
This
provision
will
curtail
peaks
by
providing
systems
with
and
reduce
exposure
proactive
approach
to
high
DBP
levelsremain
in
compliance.
Operational
evaluation
requirements
are
discussed
in
greater
detail
in
Section
IV.
H.

4.
Consecutive
systems
The
Stage
2
DBPR
also
contains
provisions
for
regulating
consecutive
systems,
defined
in
the
Stage
2
DBPR
as
public
water
systems
that
buy
or
otherwise
receive
some
or
all
of
their
finished
water
from
another
public
water
system
on
a
regular
basis.
Uniform
regulation
of
consecutive
systems
provided
by
the
Stage
2
DBPR
will
ensure
that
consecutive
systems
deliver
drinking
water
that
meets
applicable
DBP
standards,
thereby
providing
better,
more
equitable
public
health
protection.
More
information
on
regulation
of
consecutive
systems
can
be
found
in
Sections
IV.
B,
IV.
E,
and
IV.
G.

C.
Correction
of
§
141.132
Section
553
of
the
Administrative
Procedure
Act,
5
U.
S.
C.
553(
b)(
B),
provides
that,

when
an
agency
for
good
cause
finds
that
notice
and
public
procedure
are
impracticable,

unnecessary,
or
contrary
to
the
public
interest,
the
agency
may
issue
a
rule
without
providing
prior
notice
and
an
opportunity
for
public
comment.
In
addition
to
promulgating
the
Stage
2
22
regulations,
this
rule
also
makes
a
minor
correction
to
the
National
Primary
Drinking
Water
Regulations,
specifically
the
Stage
1
Disinfection
Byproducts
Rule.
This
rule
corrects
a
technical
drafting
error
made
in
the
January
16,
2001,
Federal
Register
Notice
(
66
FR
3769)
(
see
page
3770).
This
rule
replacesrestores
the
following
sentence
that
was
inadvertently
removed
from
§
141.132
(
b)(
1)(
iii),
"
Systems
on
a
reduced
monitoring
schedule
may
remain
on
that
reduced
schedule
as
long
as
the
average
of
all
samples
taken
in
the
year
(
for
systems
which
must
monitor
quarterly)
or
the
result
of
the
sample
(
for
systems
which
must
monitor
no
more
frequently
than
annually)
is
no
more
than
0.060
mg/
L
and
0.045
mg/
L
for
TTHMs
and
HAA5,
respectively."

This
text
had
been
part
of
the
original
regulation
when
it
was
codified
in
the
CFR
on
December
16,
1998.
However,
as
a
result
of
a
subsequent
amendment
to
that
regulatory
text,
the
text
discussed
today
was
removed.
EPA
recognized
the
error
only
after
publication
of
the
new
amendment,
and
is
now
correcting
the
error.
EPA
is
merely
restoring
to
the
CFR
language
that
EPA
had
promulgated
on
December
16,
1998.
EPA
is
not
creating
any
new
rights
or
obligations
by
this
technical
correction.
Thus,
additional
notice
and
public
comment
is
not
necessary.
EPA
finds
that
this
constitutes
"
good
cause"
under
5
U.
S.
C.
553(
b)(
B).
For
the
same
reasons,
EPA
is
making
this
rule
change
effective
upon
publication.
5
U.
S.
C.
553(
d)(
3).

III.
Background
A
combination
of
factors
influenced
the
development
of
the
Stage
2
DBPR.
These
include
the
initial
1992­
1994
Microbial
and
Disinfection
Byproduct
(
M­
DBP)
stakeholder
deliberations
and
EPA's
Stage
1
DBPR
proposal
(
USEPA
1994);
the
1996
Safe
Drinking
Water
Act
(
SDWA)

Amendments;
the
1996
Information
Collection
Rule;
the
1998
Stage
1
DBPR;
new
data,
research,
23
and
analysis
on
disinfection
byproduct
(
DBP)
occurrence,
treatment,
and
health
effects
since
the
Stage
1
DBPR;
and
the
Stage
2
DBPR
Microbial
and
Disinfection
Byproducts
Federal
Advisory
Committee.
The
following
sections
provide
summary
background
information
on
these
subjects.

For
additional
information,
see
the
proposed
Stage
2
DBPR
and
supporting
technical
material
where
cited
(
68
FR
49548,
August
18,
2003)
(
USEPA
2003a).

A.
Statutory
Requirements
and
Legal
Authority
The
SDWA,
as
amended
in
1996,
authorizes
EPA
to
promulgate
a
national
primary
drinking
water
regulation
(
NPDWR)
and
publish
a
maximum
contaminant
level
goal
(
MCLG)
for
any
contaminant
the
Administrator
determines
"
may
have
an
adverse
effect
on
the
health
of
persons,"
is
"
known
to
occur
or
there
is
a
substantial
likelihood
that
the
contaminant
will
occur
in
public
water
systems
with
a
frequency
and
at
levels
of
public
health
concern,"
and
for
which
"
in
the
sole
judgement
of
the
Administrator,
regulation
of
such
contaminant
presents
a
meaningful
opportunity
for
health
risk
reduction
for
persons
served
by
public
water
systems"
(
SDWA
section
1412
(
b)(
1)(
A)).
MCLGs
are
non­
enforceable
health
goals
set
at
a
level
at
which
"
no
known
or
anticipated
adverse
effects
on
the
health
of
persons
occur
and
which
allows
an
adequate
margin
of
safety."
These
health
goals
are
published
at
the
same
time
as
the
NPDWR
(
SDWA
sections
1412(
b)(
4)
and
1412(
a)(
3)).

SDWA
also
requires
each
NPDWR
for
which
an
MCLG
is
established
to
specify
an
MCL
that
is
as
close
to
the
MCLG
as
is
feasible
(
sections
1412(
b)(
4)
and
1401(
1)(
cC)).
The
Agency
may
also
consider
additional
health
risks
from
other
contaminants
and
establish
an
MCL
"
at
a
level
other
than
the
feasible
level,
if
the
technology,
treatment
techniques,
and
other
means
used
24
to
determine
the
feasible
level
would
result
in
an
increase
in
the
health
risk
from
drinking
water
by 
(
i)
increasing
the
concentration
of
other
contaminants
in
drinking
water;
or
(
ii)
interfering
with
the
efficacy
of
drinking
water
treatment
techniques
or
processes
that
are
used
to
comply
with
other
national
primary
drinking
water
regulations"
(
section
1412(
b)(
5)(
A)).
When
establishing
an
MCL
or
treatment
technique
under
this
authority,
"
the
level
or
levels
or
treatment
techniques
shall
minimize
the
overall
risk
of
adverse
health
effects
by
balancing
the
risk
from
the
contaminant
and
the
risk
from
other
contaminants
the
concentrations
of
which
may
be
affected
by
the
use
of
a
treatment
technique
or
process
that
would
be
employed
to
attain
the
maximum
contaminant
level
or
levels"
(
section
1412(
b)(
5)(
B)).
In
today's
rule,
the
Agency
is
establishing
MCLGs
and
MCLs
for
certain
DBPs,
as
described
in
Section
IV.

Finally,
section
1412
(
b)(
2)(
C)
of
the
Act
requires
EPA
to
promulgate
a
Stage
2
DBPR
18
months
after
promulgation
of
the
Long
Term
1
Enhanced
Surface
Water
Treatment
Rule
(
LT1ESWTR).
Consistent
with
statutory
requirementsprovisions
for
risk
balancing
(
section
1412(
b)(
5)(
B)),
EPA
is
finalizing
the
LT2ESWTR
concurrently
with
the
Stage
2
DBPR
to
ensure
simultaneous
protection
from
microbial
and
DBP
risks.

B.
What
is
the
Regulatory
History
of
the
Stage
2
DBPR
and
How
Were
Stakeholders
Involved?

This
section
first
summarizes
the
existing
regulations
aimed
at
controlling
levels
of
DBPs
in
drinking
water.
The
Stage
2
DBPR
establishes
regulatory
requirements
beyond
these
rules
that
target
high
risk
systems
and
provide
for
more
equitable
protection
from
DBPs
across
the
entire
distribution
system.
Next,
this
section
summarizes
the
extensive
stakeholder
involvement
in
the
development
of
the
Stage
2
DBPR.
25
1.
Total
Trihalomethanes
Rule
The
first
rule
to
regulate
DBPs
was
promulgated
on
November
29,
1979.
The
Total
Trihalomethanes
Rule
(
44
FR
68624,
November
29,
1979)
(
USEPA
1979)
set
an
MCL
of
0.10
mg/
L
for
total
trihalomethanes
(
TTHM).
Compliance
was
based
on
the
running
annual
average
(
RAA)
of
quarterly
averages
of
all
samples
collected
throughout
the
distribution
system.
This
TTHM
standard
applied
only
to
community
water
systems
using
surface
water
and/
or
ground
water
that
served
at
least
10,000
people
and
added
a
disinfectant
to
the
drinking
water
during
any
part
of
the
treatment
process.

2.
Stage
1
Disinfectants
and
Disinfection
Byproducts
Rule
The
Stage
1
DBPR,
finalized
in
1998
(
USEPA
1998a),
applies
to
all
community
and
nontransient
noncommunity
water
systems
that
add
a
chemical
disinfectant
to
water.
The
rule
established
maximum
residual
disinfectant
level
goals
(
MRDLGs)
and
enforceable
maximum
residual
disinfectant
level
(
MRDL)
standards
for
three
chemical
disinfectants
 
chlorine,

chloramine,
and
chlorine
dioxide;
maximum
contaminant
level
goals
(
MCLGs)
for
three
trihalomethanes
(
THMs),
two
haloacetic
acids
(
HAAs),
bromate,
and
chlorite;
and
enforceable
maximum
contaminant
level
(
MCL)
standards
for
TTHM,
five
haloacetic
acids
(
HAA5),
bromate
(
calculated
as
running
annual
averages
(
RAAs)),
and
chlorite
(
based
on
daily
and
monthly
sampling).
The
Stage
1
DBPR
uses
TTHM
and
HAA5
as
indicators
of
the
various
DBPs
that
are
present
in
disinfected
water.
Under
the
Stage
1
DBPR,
water
systems
that
use
surface
water
or
ground
water
under
the
direct
influence
of
surface
water
and
use
conventional
filtration
treatment
are
required
to
remove
specified
percentages
of
organic
materials,
measured
as
total
organic
carbon
(
TOC),
that
may
react
with
disinfectants
to
form
DBPs.
Removal
is
achieved
through
26
enhanced
coagulation
or
enhanced
softening,
unless
a
system
meets
one
or
more
alternative
compliance
criteria.

The
Stage
1
DBPR
was
one
of
the
first
rules
to
be
promulgated
under
the
1996
SDWA
Amendments
(
USEPA
1998a).
EPA
finalized
the
Interim
Enhanced
Surface
Water
Treatment
Rule
(
63
FR
69477,
December
16,
1998)
(
USEPA
1998b)
at
the
same
time
as
the
Stage
1
DBPR
to
ensure
simultaneous
compliance
and
address
risk
tradeoff
issues.
Both
rules
were
products
of
extensive
Federal
Advisory
Committee
deliberations
and
final
consensus
recommendations
in
1997.

3.
Stakeholder
involvement
a.
Federal
Advisory
Committee
process.
EPA
reconvened
the
M­
DBP
Advisory
Committee
in
March
1999
to
develop
recommendations
on
issues
pertaining
to
the
Stage
2
DBPR
and
LT2ESWTR.
The
Stage
2
M­
DBP
Advisory
Committee
consisted
of
21
organizational
members
representing
EPA,
State
and
local
public
health
and
regulatory
agencies,
local
elected
officials,
Native
American
Tribes,
large
and
small
drinking
water
suppliers,
chemical
and
equipment
manufacturers,
environmental
groups,
and
other
stakeholders.
Technical
support
for
the
Advisory
Committee's
discussions
was
provided
by
a
technical
working
group
established
by
the
Advisory
Committee.
The
Advisory
Committee
held
ten
meetings
from
September
1999
to
July
2000,
which
were
open
to
the
public,
with
an
opportunity
for
public
comment
at
each
meeting.

The
Advisory
Committee
carefully
considered
extensive
new
data
on
the
occurrence
and
health
effects
of
DBPs,
as
well
as
costs
and
potential
impacts
on
public
water
systems.
In
addition,
they
considered
risk
tradeoffs
associated
with
treatment
changes.
Based
upon
this
27
detailed
technical
evaluation,
the
committee
concluded
that
a
targeted
protective
public
health
approach
should
be
taken
to
address
exposure
to
DBPs
beyond
the
requirements
of
the
Stage
1
DBPR.
While
there
had
been
substantial
research
to
date,
the
Advisory
Committee
also
concluded
that
significant
uncertainty
remained
regarding
the
risk
associated
with
DBPs
in
drinking
water.
After
reaching
these
conclusions,
the
Advisory
Committee
developed
an
Agreement
in
Principle
(
65
FR
83015,
December
29,
2000)
(
USEPA
2000a)
that
laid
out
their
consensus
recommendations
on
how
to
further
control
DBPs
in
public
water
systems,
which
are
reflected
in
today's
final
rule.

In
the
Agreement
in
Principle,
the
Advisory
Committee
recommended
maintaining
the
MCLs
for
TTHM
and
HAA5
at
0.080
mg/
L
and
0.060
mg/
L,
respectively,
but
changing
the
compliance
calculation
in
two
phases
to
facilitate
systems
moving
from
the
running
annual
average
(
RAA)
calculation
to
a
locational
running
annual
average
(
LRAA)
calculation.
In
the
first
phase,
systems
would
continue
to
comply
with
the
Stage
1
DBPR
MCLs
as
RAAs
and,
at
the
same
time,
comply
with
MCLs
of
0.120
mg/
L
for
TTHM
and
0.100
mg/
L
for
HAA5
calculated
as
LRAAs.
RAA
calculations
average
all
samples
collected
within
a
distribution
system
over
a
oneyear
period,
but
LRAA
calculations
average
all
samples
taken
at
each
individual
sampling
location
in
a
distribution
system
during
a
one­
year
period.
Systems
would
also
carry
out
an
Initial
Distribution
System
Evaluation
(
IDSE)
to
select
compliance
monitoring
sites
that
more
accurately
reflect
higher
TTHM
and
HAA5
levels
occurring
in
the
distribution
system.
The
second
phase
of
compliance
would
require
MCLs
of
0.080
mg/
L
for
TTHM
and
0.060
mg/
L
for
HAA5,
calculated
as
LRAAs
at
individual
monitoring
sites
identified
through
the
IDSE.
The
first
phase
has
been
dropped
in
the
final
rule,
as
discussed
in
section
IV.
C.
28
The
Agreement
in
Principle
also
provided
recommendations
for
simultaneous
compliance
with
the
LT2ESWTR
so
that
the
reduction
of
DBPs
does
not
compromise
microbial
protection.

The
complete
text
of
the
Agreement
in
Principle
(
USEPA
2000a)
can
be
found
online
at
the
edocket
website
(
www.
eparegulations.
gov/
edocket)
gov.

b.
Other
outreach
processes.
EPA
worked
with
stakeholders
to
develop
the
Stage
2
DBPR
through
various
outreach
activities
other
than
the
M­
DBP
Federal
Advisory
Committee
process.
The
Agency
consulted
with
State,
local,
and
Tribal
governments;
the
National
Drinking
Water
Advisory
Committee
(
NDWAC);
the
Science
Advisory
Board
(
SAB);
and
Small
Entity
Representatives
(
SERs)
and
small
system
operators
(
as
part
of
an
Agency
outreach
initiative
under
the
Regulatory
Flexibility
Act).
Section
VII
includes
a
complete
description
of
the
many
stakeholder
activities
which
contributed
to
the
development
of
the
Stage
2
DBPR.

Additionally,
EPA
posted
a
pre­
proposal
draft
of
the
Stage
2
DBPR
preamble
and
regulatory
language
on
an
EPA
Internet
site
on
October
17,
2001.
This
public
review
period
allowed
readers
to
comment
on
the
Stage
2
DBPR's
consistency
with
the
Agreement
in
Principle
of
the
Stage
2
M­
DBP
Advisory
Committee.
EPA
received
important
suggestions
on
this
preproposal
draft
from
14
commenters,
which
included
public
water
systems,
State
governments,

laboratories,
and
other
stakeholders.

C.
Public
Health
Concerns
to
be
Addressed
EPA
is
promulgating
the
Stage
2
rule
to
reduce
the
potential
risks
of
cancer
and
reproductive
and
developmental
health
effects
from
DBPs.
In
addition,
the
provisions
of
the
Stage
2
DBPR
provide
for
more
equitable
public
health
protection.
Sections
C
and
D
describe
29
the
general
basis
for
this
public
health
concern
through
reviewing
information
in
the
following
areas:
the
health
effects
associated
with
DBPs,
DBP
occurrence,
and
the
control
of
DBPs.

1.
What
are
DBPs?

Chlorine
has
been
widely
used
to
kill
disease­
causing
microbes
in
drinking
water.
The
addition
of
chlorine
in
PWSs
across
the
U.
S.
to
kill
microbial
pathogens
in
the
water
supply
has
been
cited
as
one
of
the
greatest
public
health
advances
of
the
twentieth
century
(
Okun
2003).

For
example,
during
the
decade
1880­
1890,
American
cities
experienced
an
average
mortality
rate
of
58
per
100,000
from
typhoid,
which
was
commonly
transmitted
through
contaminated
water.

By
1938,
this
rate
had
fallen
to
0.67
deaths
per
100,000,
largely
due
to
improved
treatment
of
drinking
water
(
PageBlake
198756).

During
the
disinfection
process,
organic
and
inorganic
material
in
source
waters
can
combine
with
chlorine
and
certain
other
chemical
disinfectants
to
form
DBPs.
More
than
260
million
people
in
the
U.
S.
are
exposed
to
disinfected
water
and
DBPs
(
USEPA
2005a).
Although
chlorine
is
the
most
commonly
applied
disinfectant,
other
disinfectants,
including
ozone,
chlorine
dioxide,
chloramine,
and
ultraviolet
radiation,
are
in
use.
In
combination
with
these,
all
surface
water
systems
must
also
use
either
chlorine
or
chloramine
to
maintain
a
disinfectant
residual
in
their
distribution
system.
The
kind
of
disinfectant
used
can
produce
different
types
and
levels
of
disinfectant
byproducts
in
the
drinking
water.

Many
factors
affect
the
amount
and
kinds
of
DBPs
in
drinking
water.
Areas
in
the
distribution
system
that
have
had
longer
contact
time
with
chemical
disinfectants
tend
to
have
higher
levels
of
DBPs,
such
as
sites
farther
from
the
treatment
plant,
dead
ends
in
the
system,
and
small
diameter
pipes.
The
makeup
and
source
of
the
water
also
affect
DBP
formation.
Different
30
types
of
organic
and
inorganic
material
will
form
different
types
and
levels
of
DBPs.
Other
factors,
such
as
water
temperature,
season,
pH,
and
location
within
the
water
purification
process
where
disinfectants
are
added,
can
affect
DBP
formation
within
and
between
water
systems.

THMs
and
HAAs
are
widely
occurring
classes
of
DBPs
formed
during
disinfection
with
chlorine
and
chloramine.
The
four
THMs
(
TTHM)
and
five
HAAs
(
HAA5)
measured
and
regulated
in
the
Stage
2
DBPR
act
as
indicators
for
DBP
occurrence.
There
are
other
known
DBPs
in
addition
to
a
variety
of
unidentified
DBPs
present
in
disinfected
water.
THMs
and
HAAs
typically
occur
at
higher
levels
than
other
known
and
unidentified
DBPs
(
McGuire
et
al.

2002;
Weinberg
et
al.
2002).
The
presence
of
TTHM
and
HAA5
is
representative
of
the
occurrence
of
many
other
chlorination
DBPs;
thus,
a
reduction
in
the
TTHM
and
HAA5
generally
indicates
an
overall
reduction
of
DBPs.

2.
DBP
Health
Effects
Since
the
mid
1980'
s,
epidemiological
studies
have
supported
a
potential
association
between
bladder
cancer
and
chlorinated
water
and
possibly
also
with
colon
and
rectal
cancers.
In
addition,
more
recent
health
studies
have
reported
potential
associations
between
chlorinated
drinking
water
and
reproductive
and
developmental
health
effects.

Based
on
a
collective
evaluation
of
both
the
human
epidemiology
and
animal
toxicology
data
on
cancer
and
reproductive
and
developmental
health
effects
discussed
below
and
in
consideration
of
the
large
number
of
people
exposed
to
chlorinated
byproducts
in
drinking
water
(
more
than
260
million),
EPA
concludes
that
(
1)
new
cancer
data
since
Stage
1
strengthens
the
evidence
of
a
potential
association
of
chlorinated
water
with
bladder
cancer
and
suggests
an
association
for
colon
and
rectal
cancers,
(
2)
current
reproductive
and
developmental
health
effects
31
data
do
not
support
a
conclusion
at
this
time
as
to
whether
exposure
to
chlorinated
drinking
water
or
disinfection
byproducts
causes
adverse
developmental
or
reproductive
health
effects,
but
do
support
a
potential
hazardhealth
concern,
and
(
3)
the
combined
health
data
indicate
a
need
for
public
health
protection
beyond
that
provided
by
the
Stage
1
DBPR.

This
section
summarizes
the
key
information
in
the
areas
of
cancer,
reproductive,
and
developmental
health
studies
that
EPA
used
to
arrive
at
these
conclusions.
Throughout
this
writeup,
EPA
uses
`
weight
of
evidence,'
`
causality,'
and
`
hazard'
as
follows:

C
A
`
weight
of
evidence'
evaluation
is
a
collective
evaluation
of
all
pertinent
information.

Judgement
about
the
weight
of
evidence
involves
considerations
of
the
quality
and
adequacy
of
data
and
consistency
of
responses.
These
factors
are
not
scored
mechanically
by
adding
pluses
and
minuses;
they
are
judged
in
combination.

C
Criteria
for
determining
`
causality'
include
consistency,
strength,
and
specificity
of
association,
a
temporal
relationship,
a
biological
gradient
(
dose­
response
relationship),

biological
plausibility,
coherence
with
multiple
lines
of
evidence,
evidence
from
human
populations,
and
information
on
agent's
structural
analogues
(
USEPA
2005ji).
Additional
considerations
for
individual
study
findings
include
reliable
exposure
data,
statistical
power
and
significance,
and
freedom
from
bias
and
confounding.

C
The
term
`
hazard'
describes
not
a
definitive
conditionconclusion,
but
the
possibility
that
a
health
effect
may
be
attributed
to
a
certain
exposure,
in
this
case
chlorinated
water.

Analyses
done
for
the
Stage
2
DBPR
follow
the
1999
EPA
Proposed
Guidelines
for
Carcinogenic
Risk
Assessment
(
USEPA
1999a).
In
March
2005,
EPA
updated
and
finalized
the
Cancer
Guidelines
and
a
Supplementary
Children's
Guidance,
which
include
new
considerations
32
on
mode
of
action
for
cancer
risk
determination
and
additional
potential
risks
due
to
early
childhood
exposure
(
USEPA
2005ji;
USEPA
2005kj).
Conducting
the
cancer
evaluation
using
the
2005
Cancer
Guidelines
would
not
result
in
any
change
from
the
existing
analysis.
With
the
exception
of
chloroform,
no
mode
of
action
has
been
established
for
other
specific
regulated
DBPs.
Although
some
of
the
DBPs
have
given
mixed
mutagenicity
and
genotoxicity
results,

having
a
positive
mutagenicity
study
does
not
necessarily
mean
that
a
chemical
has
a
mutagenic
mode
of
action.
The
extra
factor
of
safety
for
children's
health
protection
does
not
apply
because
the
new
Supplementary
Children's
Guidance
requires
application
of
the
children's
factor
only
when
a
mutagenic
mode
of
action
has
been
identified.

a.
Cancer
health
effects.
The
following
section
briefly
discusses
cancer
epidemiology
and
toxicology
information
EPA
analyzed
and
some
conclusions
of
these
studies
and
reports.
Further
discussion
of
these
studies
and
EPA's
conclusions
can
be
found
in
the
proposed
Stage
2
DBPR
(
USEPA
2003a)
and
the
Stage
2
Economic
Analysis
for
the
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
(
Economic
Analysis
(
EA))
(
USEPA
2005a).

Human
epidemiology
studies
and
animal
toxicology
studies
have
examined
associations
between
chlorinated
drinking
water
or
DBPs
and
cancer.
While
EPA
cannot
conclude
there
is
a
causal
link
between
exposure
to
chlorinated
surface
water
and
cancer,
EPA
believes
that
the
available
research
indicates
a
potential
association
between
bladder
cancer
and
exposure
to
chlorinated
drinking
water
or
DBPs.
EPA
also
believes
the
available
research
suggests
a
possible
association
between
rectal
and
colon
cancers
and
exposure
to
chlorinated
drinking
water
or
DBPs.
This
is
based
on
EPA's
evaluation
of
all
available
cancer
studies.
The
next
two
sections
focus
on
studies
published
since
the
Stage
1
DBPR.
Conclusions
are
based
on
the
research
as
a
33
whole.

i.
Epidemiology.
A
number
of
epidemiological
studies
have
been
conducted
to
investigate
the
relationship
between
exposure
to
chlorinated
drinking
water
and
various
cancers.
These
studies
contribute
to
the
overall
evidence
on
potential
human
health
hazards
from
exposure
to
chlorinated
drinking
water.

Epidemiology
studies
provide
useful
health
effects
information
because
they
reflect
human
exposure
to
a
drinking
water
DBP
mixture
through
multiple
routes
of
intake
such
as
ingestion,

inhalation
and
dermal
absorption.
The
greatest
difficulty
with
conducting
cancer
epidemiology
studies
is
the
length
of
time
between
exposure
and
effect.
Higher
quality
studies
have
adequately
controlled
for
confounding
and
have
limited
the
potential
for
exposure
misclassification,
for
example,
using
DBP
levels
in
drinking
water
as
the
exposure
metric
as
opposed
to
type
of
source
water.
Study
design
considerations
for
interpreting
cancer
epidemiology
data
include
sufficient
follow­
up
time
to
detect
disease
occurrence,
adequate
sample
size,
valid
ascertainment
of
cause
of
the
cancer,
and
reduction
of
potential
selection
bias
in
case­
control
and
cohort
studies
(
by
having
comparable
cases
and
controls
and
by
limiting
loss
to
follow­
up).
Epidemiology
studies
provide
extremely
useful
information
on
human
exposure
to
chlorinated
water,
which
is
preferable
overcomplement
single
chemical,
high
dose
animal
data.

In
the
Stage
1
DBPR,
EPA
concluded
that
the
epidemiological
evidence
suggested
a
potential
increased
risk
for
bladder
cancer.
Some
key
studies
EPA
considered
for
Stage
1
include
Cantor
et
al.
(
1998),
Doyle
et
al.
(
1997),
Freedman
et
al.
(
1997),
King
and
Marrett
(
1996),

McGeehin
et
al.
(
1993),
Cantor
et
al.
(
1987),
and
Cantor
et
al.
(
1985).
Several
studies
published
since
the
Stage
1
DBPR
continue
to
support
an
association
between
increased
risk
of
bladder
34
cancer
and
exposure
to
chlorinated
surface
water
(
Chevrier
et
al.
2004;
Koivusalo
et
al.
1998;

Yang
et
al.
1998).
One
study
found
no
effects
foron
a
biomarker
of
genotoxicity
in
urinary
bladder
cells
andfrom
TTHM
exposure
(
Ranmuthugala
et
al.
2003).
Epidemiological
reviews
and
meta­
analyses
generally
support
the
possibility
of
an
association
between
chlorinated
water
or
THMs
and
bladder
cancer
(
Villanueva
et
al.
2004;
Villanueva
et
al.
2003;
Villanueva
et
al.
2001;

Mills
et
al.
1998).
The
World
Health
Organization
(
WHO
2000)
found
data
inconclusive
or
insufficient
to
determine
causality
between
chlorinated
water
and
any
health
endpoint,
although
they
concluded
that
the
evidence
is
better
for
bladder
cancer
than
for
other
cancers.

In
the
Stage
1
DBPR,
EPA
concluded
that
early
studies
suggested
a
small
possible
increase
in
rectal
and
colon
cancers
from
exposure
to
chlorinated
surface
waters.
The
database
of
studies
on
colon
and
rectal
cancers
continues
to
support
a
possible
association,
but
evidence
remains
mixed.
For
colon
cancer,
one
newer
study
supports
the
evidence
of
an
association
(
King
et
al.
2000a)
while
others
showed
inconsistent
findings
(
Hildesheim
et
al.
1998;
Yang
et
al.

1998).
Rectal
cancer
studies
are
also
mixed.
Hildesheim
et
al.
(
1998)
and
Yang
et
al.
(
1998)

support
an
association
with
rectal
cancer
while
King
et
al.
(
2000a)
did
not.
A
review
of
colon
and
rectal
cancer
concluded
evidence
was
inconclusive
but
that
there
was
a
stronger
association
for
rectal
cancer
and
chlorination
DBPs
than
for
colon
cancer
(
Mills
et
al.
1998).
The
WHO
(
2000)
review
reported
that
studies
showed
weak
to
moderate
associations
with
colon
and
rectal
cancers
and
chlorinated
surface
water
or
THMs
but
that
evidence
is
inadequate
to
evaluate
these
associations.

Recent
studies
on
kidney,
brain,
and
lung
cancers
and
DBP
exposure
support
a
possible
association
(
kidney:
Yang
et
al.
1998,
Koivusalo
et
al.
1998;
brain:
Cantor
et
al.
1999;
lung:
35
Yang
et
al.
1998).
However,
so
few
studies
have
examined
these
endpoints
that
definitive
conclusions
cannot
be
made.
Studies
on
leukemia
found
little
or
no
association
with
DBPs
(
Infante­
Rivard
et
al.
2002;
Infante­
Rivard
et
al.
2001).
A
recent
study
did
not
find
an
association
between
pancreatic
cancer
and
DBPs
(
Do
et
al.
2005).
A
study
researching
multiple
cancer
endpoints
found
an
association
between
THM
exposure
and
all
cancers
when
grouped
together
(
Vinceti
et
al.
2004).
More
details
on
the
cancer
epidemiology
studies
since
the
Stage
1
DBPR
are
outlined
in
Table
II.
D­
1.
36
Table
II.
D­
1.
Summary
of
Cancer
Epidemiology
Studies
Reviewed
for
Stage
2
DBPR.

Author(
s)
Study
Type
Exposure(
s)
Studied
Outcome(
s)

Measured
Findings
Do
et
al.
2005
Case­
control
study
in
Canada,
1994­

1997.
Estimated
chlorinated
DBPs,
chloroform,
BDCM
concentrations.
Pancreatic
cancer.
No
association
was
found
between
pancreatic
cancer
and
exposure
to
chlorinated
DBPs,
chloroform,
or
BDCM.

Chevrier
et
al.

2004
Case­
control
study
in
France,
1985­

1987.
Compared
THM
levels,

duration
of
exposure,
and
3
types
of
water
treatment
(
ozonation,
chlorination,

ozonation/
chlorination).
Bladder
cancer.
A
statistically
significant
decreased
risk
of
bladder
cancer
was
found
as
duration
of
exposure
to
ozonated
water
increased.
This
was
evident
with
and
without
adjustment
for
other
exposure
measures.
A
small
increased
risk
and
trendassociation
was
detected
for
increased
bladder
cancer
risk
and
duration
of
exposure
to
chlorinated
surface
water
and
with
the
estimated
THM
content
of
the
water,
achieving
statistical
significance
only
when
adjusted
for
duration
of
ozonated
water
exposures.
Effect
modification
by
gender
was
noted
in
the
adjusted
analyses.

Vinceti
et
al.

2004
Retrospective
cohort
study
in
Italy,
1987­
1999.
Standardized
mortality
ratios
from
all
causes
vs.

cancer
for
consumers
drinking
water
with
high
THMs.
15
cancers
including
colon,

rectum,
and
bladder.
Mortality
ratio
from
all
cancers
showed
a
statistically
significant
small
increase
for
males
consuming
drinking
water
with
high
THMs.
For
females,
an
increased
mortality
ratio
for
all
cancers
was
seen
but
was
not
statistically
significant.
Stomach
cancer
in
men
was
the
only
individual
cancer
in
which
a
statistically
significant
excess
in
mortality
was
detected
for
consumption
of
drinking
water
with
high
THMs.

Ranmuthugala
et
al.
2003
Cohort
study
in
3
Australian
communities,

1997.
Estimated
dose
of
TTHM,

chloroform,
and
bromoform
from
routinely­
collected
THM
measurements
and
fluid
intake
diary.
Frequency
of
micronuclei
in
urinary
bladder
epithelial
cells.
Relative
risk
estimates
for
DNA
damage
to
bladder
cells
for
THM
dose
metrics
were
near
1.0.
The
study
provides
no
evidence
that
THMs
are
associated
with
DNA
damage
to
bladder
epithelial
cells,
and
dose­
response
patterns
were
not
detected.

Infante­
Rivard
et
al.
2002
Population­
based
case­
control
study
in
Quebec,
1980­

1993.
Estimated
prenatal
and
postnatal
exposure
to
THMs
and
polymorphisms
in
two
genes.
Acute
lymphoblastic
leukemia.
Data
are
suggestive,
but
imprecise,
linking
DNA
variants
with
risk
of
acute
lymphoblastic
leukemia
associated
with
drinking
water
DBPs.
The
number
of
genotyped
subjects
for
GSTT1
and
CYP2E1
genes
was
too
small
to
be
conclusive.

Infante­
Rivard
et
al.
2001
Population­
based
case­
control
study
in
Quebec,
1980­

1993.
Compared
water
chlorination
(
never,

sometimes,
always)
and
exposure
to
TTHMs,
metals,

and
nitrates.
Acute
lymphoblastic
leukemia.
No
increased
risk
for
lymphoblastic
leukemia
was
observed
for
prenatal
exposure
at
average
levels
of
TTHMs,
metals
or
nitrates.
However,
a
nonstatistically
significant,
small
increased
risk
was
seen
for
postnatal
cumulative
exposure
to
TTHMs
and
chloroform
(
both
at
above
the
95th
exposure
percentile
of
the
distribution
for
cases
and
controls),
for
zinc,
cadmium,
and
arsenic,
but
not
other
metals
or
nitrates.

King
et
al.

2000a
Population­
based
case­
control
study
in
southern
Compared
source
of
drinking
water
and
chlorination
status.
Colon
and
rectal
cancer.
Colon
cancer
risk
was
statistically
associated
with
cumulative
long
term
exposure
to
THMs,
chlorinated
surface
water,
and
tap
water
consumption
metrics
among
males
only.
Exposure­
response
relationships
were
evident
for
37
Ontario,
1992­

1994.
Estimated
TTHM
levels,

duration
of
exposure,
and
tap
water
consumption.
exposure
measures
combining
duration
and
THM
levels.
Associations
between
the
exposure
measures
and
rectal
cancer
were
not
observed
for
either
gender.

Cantor
et
al.

1999
Population­
based
case­
control
study
in
Iowa,
1984­

1987.
Compared
level
and
duration
of
THM
exposure
(
cumulative
and
average),

source
of
water,

chlorination,
and
water
consumption.
Brain
cancer.
Among
males,
a
statistically
significant
increased
risk
of
brain
cancer
was
detected
for
duration
of
chlorinated
versus
non­
chlorinated
source
water,

especially
among
high­
level
consumers
of
tap
water.
An
increased
risk
of
brain
cancer
for
high
water
intake
level
was
found
in
men.
No
associations
were
found
for
women
for
any
of
the
exposure
metrics
examined.

Cantor
et
al.

1998
Population­
based
case­
control
study
in
Iowa,
1986­

1989.
Compared
level
and
duration
of
THM
exposure
(
cumulative
and
average),

source
of
water,

chlorination,
and
water
consumption.
Bladder
cancer.
A
statistically
significant
positive
association
between
risk
of
bladder
cancer
and
exposure
to
chlorinated
groundwater
or
surface
water
reported
for
men
and
for
smokers,
but
no
association
found
for
male/
female
non­
smokers,
or
for
women
overall.
Limited
evidence
was
found
for
an
association
between
tapwater
consumption
and
bladder
cancer
risk.
Suggestive
evidence
existed
for
exposure­
response
effects
of
chlorinated
water
and
lifetime
THM
measures
on
bladder
cancer
risk.

Hildesheim
et
al.
1998
Population­
based
case­
control
study
in
Iowa,
1986­

1989.
Compared
level
and
duration
of
THM
exposure
(
cumulative
and
average),

source
of
water,

chlorination,
and
water
consumption.
Colon
and
rectal
cancer.
Increased
risks
of
rectal
cancer
was
associated
with
duration
of
exposure
to
chlorinated
surface
water
and
any
chlorinated
water,
with
evidence
of
an
exposure­
response
relationship.
Risk
of
rectal
cancer
is
statistically
significant
increased
with
>
60
years
lifetime
exposure
to
THMs
in
drinking
water,
and
risk
increased
for
individuals
with
low
dietary
fiber
intake.
Risks
were
similar
for
men
and
women
and
no
effects
were
observed
for
tapwater
measures.
No
associations
were
detected
for
water
exposure
measures
and
risk
of
colon
cancer.

Koivusalo
et
al.

1998
Population­
based
case­
control
study
in
Finland,
1991­

1992.
Estimated
residential
duration
of
exposure
and
level
of
drinking
water
mutagenicity.
Bladder
and
kidney
cancer.
Drinking
water
mutagenicity
was
associated
with
a
small,
statistically
significant,
exposure­
related
excess
risk
for
kidney
and
bladder
cancers
among
men;
weaker
associations
were
detected
for
mutagenic
water
and
bladder
or
kidney
cancer
among
women.
The
effect
of
mutagenicity
on
bladder
cancer
was
modified
by
smoking
status,
with
an
increased
risk
among
non­
smokers.

Yang
et
al.
1998
Cross­
sectional
study
in
Taiwan,

1982­
1991.
Examined
residence
in
chlorinated
(
mainly
surface
water
sources)
relative
to
non­
chlorinated
(
mainly
private
well)
water.
Cancer
of
rectum,
lung,

bladder,
kidney,

colon,
and
11
others.
Residence
in
chlorinating
municipalities
(
vs.
non­
chlorinating)
was
statistically
significantly
associated
with
the
following
types
of
cancer
in
both
males
and
females:
rectal,
lung,
bladder,
and
kidney
cancer.
Liver
cancer
and
all
cancers
were
also
statistically
significantly
elevated
in
chlorinated
towns
for
males
only.
Mortality
rates
for
cancers
of
the
esophagus,
stomach,
colon,
pancreas,

prostate,
brain,
breast,
cervix
uteri
and
uterus,
and
ovary
were
comparable
for
chlorinated
and
non­
chlorinated
residence.

Doyle
et
al.

1997
Prospective
cohort
study
in
Iowa,

1987­
1993.
Examined
chloroform
levels
and
source
of
drinking
water.
Colon,
rectum,

bladder,
and
8
other
cancers
in
Statistically
significant
increased
risk
of
colon
cancer,
breast
cancer
and
all
cancers
combined
was
observed
for
women
exposed
to
chloroform
in
drinking
water,
with
evidence
of
exposure­
response
effects.
No
associations
were
38
women.
detected
between
chloroform
and
bladder,
rectum,
kidney,
upper
digestive
organs,
lung,
ovary,
endometrium,
or
breast
cancers,
or
for
melanomas
or
non­

Hodgkin's
lymphoma.
Surface
water
exposure
(
compared
to
ground
water
users)
was
also
a
significant
predictor
of
colon
and
breast
cancer
risk.

Freedman
et
al.

1997
Population­
based
case­
control
study
in
Maryland,

1975­
1992.
Estimated
duration
of
exposure
to
chlorinated
water.
Compared
exposure
to
chlorinated
municipal
water
(
yes/
no).
Bladder
cancer.
There
was
a
weak
association
between
bladder
cancer
risk
and
duration
of
exposure
to
municipal
water
for
male
cigarette
smokers,
as
well
as
an
exposure­
response
relationship.
No
association
was
seen
for
those
with
no
history
of
smoking,
suggesting
that
smoking
may
modify
a
possible
effect
of
chlorinated
surface
water
on
the
risk
of
bladder
cancer.

King
and
Marrett
1996
Case­
control
study
in
Ontario,

Canada,
1992­

1994.
Compared
source
of
drinking
water
and
chlorination
status.

Estimated
TTHM
levels,

duration
of
exposure,
and
tap
water
consumption.
Bladder
cancer.
Statistically
significant
associations
were
detected
for
bladder
cancer
and
chlorinated
surface
water,
duration
or
concentration
of
THM
levels
and
tap
water
consumption
metrics.
Population
attributable
risks
were
estimated
at
14
to
16
percent.
An
exposure­
response
relationship
was
observed
for
estimated
duration
of
high
THM
exposures
and
risk
of
bladder
cancer.

McGeehin
et
al.

1993
Population­
based
case­
control
study
in
Colorado,
1990­

1991.
Compared
source
of
drinking
water,
water
treatment,
and
tap
water
versus
bottled
water.

Estimated
duration
of
exposure
to
TTHMs
and
levels
of
TTHMs,
nitrates,

and
residual
chlorine.
Bladder
cancer.
Statistically
significant
associations
were
detected
for
bladder
cancer
and
duration
of
exposure
to
chlorinated
surface
water.
The
risk
was
similar
for
males
and
females
and
among
nonsmokers
and
smokers.
The
attributable
risk
was
estimated
at
14.9
percent.
High
tap
water
intake
was
associated
with
risk
of
bladder
cancer
in
a
exposure­
response
fashion.
No
associations
were
detected
between
bladder
cancer
and
levels
of
TTHMs,
nitrates,
and
residual
chlorine.

Cantor
et
al.

1987
(
and
Cantor
et
al.

1985)
Population­
based
case­
control
study
in
10
areas
of
the
U.
S.,
1977­
1978.
Compared
source
of
drinking
water.
Estimated
total
beverage
and
tap
water
consumption
and
duration
of
exposure.
Bladder
cancer.
Bladder
cancer
was
statistically
associated
with
duration
of
exposure
to
chlorinated
surface
water
for
women
and
nonsmokers
of
both
sexes.
The
largest
risks
were
seen
when
both
exposure
duration
and
level
of
tap
water
ingestion
were
combined.
No
association
was
seen
for
total
beverage
consumption.

Reviews/

Metaanalyses
Study
Type
Exposure(
s)
Studied
Outcome(
s)

Measured
Findings
Villanueva
et
al.

2004
Review
and
metaanalysis
of
6
casecontrol
studies.
Individual­
based
exposure
estimates
to
THMs
and
water
consumption
over
a
40­
year
period.
Bladder
cancer.
The
meta­
analysis
suggests
that
risk
of
bladder
cancer
in
men
increases
with
long­
term
exposure
to
TTHMs.
An
exposure­
response
pattern
was
observed
among
men
exposed
to
TTHMs,
with
statistically
significant
risk
seen
at
exposures
higher
than
50
ug/
L.
No
association
between
TTHMs
and
bladder
cancer
was
seen
for
women.

Villanueva
et
al.

2003
(
and
Review
and
metaanalysis
of
6
case­
Compared
source
of
water
and
estimated
duration
of
Bladder
cancer.
The
meta­
analysis
findings
showed
a
moderate
excess
risk
of
bladder
cancer
attributable
to
long­
term
consumption
of
chlorinated
drinking
water
for
both
39
Goebell
et
al.

2004)
control
studies
and
2
cohort
studies.
exposure
to
chlorinated
drinking
water.
genders,
particularly
in
men.
Statistically
significance
seen
with
men
and
combined
both
sexes.
The
risk
was
higher
when
exposure
exceeded
40
years.

Villanueva
et
al.

2001
Qualitative
review
of
31
cancer
studies.
Compared
exposure
to
TTHM
levels,
mutagenic
drinking
water,
water
consumption,
source
water,

types
of
disinfection
(
chlorination
and
chloramination),
and
residence
times.
Cancer
of
bladder,
colon,

rectum,
and
5
other
cancers.
Review
found
that
although
results
for
cancer
studies
varied
and
were
not
always
statistically
significant,
evidence
for
bladder
cancer
is
strongest,
and
all
10
of
the
bladder
cancer
studies
showed
increased
cancer
risks
with
ingestion
of
chlorinated
water.
The
authors
felt
associations
with
chlorinated
water
and
cancer
of
the
colon,
rectum,
pancreas,
esophagus,
brain,
and
other
cancers
were
inconsistent.

WHO
2000
Qualitative
reviews
of
various
studies
in
Finland,

U.
S.,
and
Canada.
Various
exposures
to
THMs.
Various
cancers.
Studies
reviewed
reported
weak
to
moderate
increased
relative
risks
of
bladder,
colon,
rectal,
pancreatic,
breast,
brain
or
lung
cancer
associated
with
long­
term
exposure
to
chlorinated
drinking
water.
The
authors
felt
evidence
is
inconclusive
for
an
association
between
colon
cancer
and
long­
term
exposure
to
THMs;
that
evidence
is
insufficient
to
evaluate
a
causal
relationship
between
THMs
and
rectal,
bladder,
and
other
cancers.
They
found
no
association
between
THMs
and
increased
risk
of
cardiovascular
disease.

Mills
et
al.
1998
Qualitative
review
of
22
studies.
Examined
TTHM
levels
and
water
consumption.

Compared
source
of
water
and
2
types
of
water
treatment
(
chlorination
and
chloramination).
Cancer
of
colon,

rectum,
and
bladder.
Review
suggests
possible
increases
in
risks
of
bladder
cancer
with
exposure
to
chlorinated
drinking
water.
The
authors
felt
evidence
for
increased
risk
of
colon
and
rectal
cancers
is
inconclusive,
though
evidence
is
stronger
for
rectal
cancer.
40
Overall,
bladder
cancer
data
provides
the
strongest
basis
for
quantifying
cancer
risks
from
DBPs.
EPA
has
chosen
this
endpoint
to
estimate
the
primary
benefits
of
the
Stage
2
DBPR
(
see
Section
VI).

ii.
Toxicology.
Cancer
toxicology
studies
provide
additional
support
that
chlorinated
water
is
associated
with
cancer.
In
general,
EPA
uses
long
term
toxicology
studies
that
show
a
dose
response
to
derive
MCLGs
and
cancer
potency
factors.
Short
term
studies
are
used
for
hazard
identification
and
to
design
long
term
studies.
Much
of
the
available
cancer
toxicology
information
was
available
for
the
Stage
1
DBPR,
but
there
have
also
been
a
number
of
new
cancer
toxicology
and
mode
of
action
studies
completed
since
the
Stage
1
DBPR
was
finalized
in
December
1998.

In
support
of
this
rule,
EPA
has
developed
health
criteria
documents
which
summarize
the
available
toxicology
data
for
brominated
THMs
(
USEPA
2005b),
brominated
HAAs
(
USEPA
2005c),
MX
(
USEPA
2000b),
MCAA
(
USEPA
2005d),
and
TCAA
(
USEPA
2005e).
The
2003
IRIS
assessment
of
DCAA
(
USEPA
2003b)
and
an
addendum
(
USEPA
2005lk)
also
provides
analysis
released
after
Stage
1.
It
summarizes
information
on
exposure
from
drinking
water
and
develops
a
slope
factor
for
DCAA.
IRIS
also
has
toxicological
reviews
for
chloroform
(
USEPA
2001a),
chlorine
dioxide
and
chlorite
(
USEPA
2000c),
and
bromate
(
USEPA
2001b),
and
is
currently
reassessing
TCAA.

Slope
factors
and
risk
concentrations
for
BDCM,
bromoform,
DBCM
and
DCAA
have
been
developed
and
are
listed
in
Table
II.
D­
2.
For
BDCM,
bromoform,
and
DBCM,
table
values
are
derived
from
the
brominated
THM
criteria
document
(
USEPA
2005b),
which
uses
IRIS
numbers
that
have
been
updated
using
the
1999
EPA
Proposed
Guidelines
for
Carcinogenic
Risk
41
Assessment
(
USEPA
1999a).
For
DCAA,
the
values
are
derived
directly
from
IRIS.

Table
II.
D­
2.
Quantification
of
Cancer
Risk.

LED
10
a
ED
10
a
Disinfection
Byproduct
Slope
Factor
(
mg/
kg/
day)­
1
10­
6
Risk
Concentration
(
mg/
L)
Slope
Factor
(
mg/
kg/
day)­
1
10­
6
Risk
Concentration
(
mg/
L)

Bromodichloromethane
0.034
0.001
0.022
0.002
Bromoform
0.0045
0.008
0.0034
0.01
Dibromochloromethane
0.04
0.0009
0.017
0.002
Dichloroacetic
Acid
0.048
0.0007
0.015
b
0.0023
b
a
LED10
is
the
lower
95%
confidence
bound
on
the
(
effective
dose)
ED10
value.
ED10
is
the
estimated
dose
producing
effects
in
10%
of
animals.
b
The
ED10
risk
factors
for
DCAA
have
been
changed
from
those
given
in
the
comparable
table
in
the
proposed
Stage
2
DBPR
to
correct
for
transcriptional
errors.

More
research
on
DBPs
is
underway
at
EPA
and
other
research
institutions.
Summaries
of
on­
going
studies
may
be
found
on
EPA's
DRINK
website
(
http://
www.
epa.
gov/
safewater/
drink/
intro.
html).
Two­
year
bioassays
by
the
National
Toxicology
Program
(
NTP)
released
in
abstract
form
have
recently
been
completed
on
BDCM
and
chlorate.
The
draft
abstract
on
BDCM
reported
no
evidence
of
carcinogenicity
when
BDCM
was
administered
via
drinking
water
(
NTP
2005a).
Another
recent
study,
a
modified
two­
year
bioassay
on
BDCM
in
the
drinking
water,
reported
little
evidence
of
carcinogenicity
(
George
et
al.
2002).
In
a
previous
NTP
study,
tumors
were
observed,
including
an
increased
incidence
of
kidney,
liver,
and
colon
tumors,
when
BDCM
was
administered
at
higher
doses
by
gavage
in
corn
oil
(
NTP
1987).
EPA
will
examine
new
information
on
BDCM
as
it
becomes
available.
In
the
chlorate
draft
abstract,
NTP
found
some
evidence
that
it
may
be
a
carcinogen
(
NTP
2004).

Chlorate
is
a
byproduct
of
hypochlorite
and
chlorine
dioxide
systems.
A
long­
term,
two­
year
42
bioassay
NTP
study
on
DBA
is
also
complete
but
has
not
yet
undergone
peer
review
(
NTP
2005b).

b.
Reproductive
and
developmental
health
effects.
Both
human
epidemiology
studies
and
animal
toxicology
studies
have
examined
associations
between
chlorinated
drinking
water
or
DBPs
and
reproductive
and
developmental
health
effects.
Based
on
an
evaluation
of
the
available
science,
EPA
believes
the
data
suggest
that
exposure
to
DBPs
is
a
potential
reproductive
and
developmental
health
hazard.

The
following
section
briefly
discusses
the
reproductive
and
developmental
epidemiology
and
toxicology
information
available
to
EPA.
Further
discussion
of
these
studies
and
EPA's
conclusions
can
be
found
in
the
proposed
Stage
2
DBPR
(
USEPA
2003a)
and
the
Stage
2
Economic
Analysis
(
USEPA
2005a).

i.
Epidemiology.
As
discussed
previously,
epidemiology
studies
have
the
strength
of
relating
human
exposure
to
DBP
mixtures
through
multiple
intake
routes.
Although
the
critical
exposure
window
for
reproductive
and
developmental
effects
is
much
smaller
than
that
for
cancer
(
generally
weeks
versus
years),
exposure
assessment
is
also
a
main
limitation
of
reproductive
and
developmental
epidemiology
studies.
Exposure
assessment
uncertainties
arise
from
limited
data
on
DBP
concentrations
and
maternal
water
usage
and
source
over
the
course
of
the
pregnancy.

However,
classification
errors
typically
push
the
true
risk
estimate
towards
the
null
value
(
Vineis
2004).
According
to
Bove
et
al.
(
2002),
"
Difficulties
in
assessing
exposure
may
result
in
exposure
misclassification
biases
that
would
most
likely
produce
substantial
underestimates
of
risk
as
well
as
distorted
or
attenuated
exposure 
response
trends."
Studies
of
rare
outcomes
(
e.
g.,

individual
birth
defects)
often
have
limited
statistical
power
because
of
the
small
number
of
cases
43
being
examined.
This
limits
the
ability
to
detect
statistically
significant
associations
for
small
to
moderate
relative
risk
estimates.
Small
sample
sizes
also
result
in
imprecision
around
risk
estimates
reflected
by
wide
confidence
intervals.
In
addition
to
the
limitations
of
individual
studies,
evaluating
reproductive
and
developmental
epidemiology
studies
collectively
is
difficult
because
of
the
methodological
differences
between
studies
and
the
wide
variety
of
endpoints
examined.
These
factors
may
contribute
to
inconsistencies
in
the
scientific
body
of
literature
as
noted
below.

More
recent
studies
tend
to
be
of
higher
quality
because
of
improved
exposure
assessments
and
other
methodological
advancements.
For
example,
studies
that
use
THM
levels
to
estimate
exposure
tend
to
be
higher
quality
than
studies
that
define
exposure
by
source
or
treatment.
These
factors
were
taken
into
account
by
EPA
when
comparing
and
making
conclusions
on
the
reproductive
and
developmental
epidemiology
literature.
What
follows
is
a
summary
of
available
epidemiology
literature
on
reproductive
and
developmental
endpoints
such
as
spontaneous
abortion,
stillbirth,
neural
tube
and
other
birth
defects,
low
birth
weight,
and
intrauterine
growth
retardation.
Information
is
grouped,
where
appropriate,
into
three
categories
on
fetal
growth,
viability,
and
malformations,
and
reviews
are
described
separately
afterward.

Table
II.
D­
3
provides
a
more
detailed
description
of
each
study
or
review.

Fetal
growth.
Many
studies
looked
for
an
association
between
fetal
growth
(
mainly
small
for
gestational
age,
low
birth
weight,
and
pre­
term
delivery)
and
chlorinated
water
or
DBPs.
The
results
from
the
collection
of
studies
as
a
whole
are
inconsistent.
A
number
of
studies
support
the
possibility
that
exposure
to
chlorinated
water
or
DBPs
are
associated
with
adverse
fetal
growth
effects
(
Infante­
Rivard
2004;
Wright
et
al.
2004;
Wright
et
al.
2003;
Källén
and
Robert
2000;
44
Gallagher
et
al.
1998;
Kanitz
et
al.
1996;
Bove
et
al.
1995;
Kramer
et
al.
1992).
Other
studies
showed
mixed
results
(
Porter
et
al.
2005;
Savitz
et
al.
2005;
Yang
2004)
or
did
not
provide
evidence
of
an
association
(
Toledano
et
al.
2005;
Jaakkola
et
al.
2001;
Dodds
et
al.
1999;
Savitz
et
al.
1995)
between
DBP
exposure
and
fetal
growth.
EPA
notes
that
recent,
higher
quality
studies
provide
some
evidence
of
an
increased
risk
of
small
for
gestational
age
and
low
birth
weight.

Fetal
viability.
While
the
database
of
epidemiology
studies
for
fetal
loss
endpoints
(
spontaneous
abortion
or
stillbirth)
remains
inconsistent
as
a
whole,
there
is
suggestive
evidence
of
an
association
between
fetal
loss
and
chlorinated
water
or
DBP
exposure.
NumerousVarious
studies
support
the
possibility
that
exposure
to
chlorinated
water
or
DBPs
is
associated
with
decreased
fetal
viability
(
Toledano
et
al.
2005;
Dodds
et
al.
2004;
King
et
al.
2000b;
Dodds
et
al.

1999;
Waller
et
al.
1998;
Aschengrau
et
al.
1993;
Aschengrau
et
al.
1989).
Many
of
the
more
recent,
higher
quality
studies
report
associations.
SomeOther
studies
did
not
support
an
association
(
Bove
et
al.
1995)
or
reported
inconclusive
results
(
Savitz
et
al.
2005;
Swan
et
al.

1998;
Savitz
et
al.
1995)
between
fetal
viability
and
exposure
to
THMs
or
tapwater.
A
recent
study
by
King
et
al.
(
2005)
found
little
evidence
of
an
association
between
stillbirths
and
haloacetic
acids
after
controlling
for
trihalomethane
exposures,
though
non­
statistically
significant
increases
in
stillbirths
were
seen
across
various
exposure
levels.

Fetal
malformations.
A
number
of
epidemiology
studies
have
examined
the
relationship
between
fetal
malformations
(
such
as
neural
tube,
oral
cleft,
cardiac,
or
urinary
defects,
and
chromosomal
abnormalities)
and
chlorinated
water
or
DBPs.
It
is
difficult
to
assess
fetal
malformations
in
aggregate
due
to
inconsistent
findings
and
disparate
endpoints
being
examined
in
45
the
available
studies.
Some
studies
support
the
possibility
that
exposure
to
chlorinated
water
or
DBPs
is
associated
with
various
fetal
malformations
(
Cedergren
et
al.
2002;
Hwang
et
al.
2002;

Dodds
and
King
2001;
Klotz
and
Pyrch
1999;
Bove
et
al.
1995;
Aschengrau
et
al.
1993).
Other
studies
found
little
evidence
(
Shaw
et
al.
2003;
Källén
and
Robert
2000;
Dodds
et
al.
1999;
Shaw
et
al.
1991)
or
inconclusive
results
(
Magnus
et
al.
1999)
between
chlorinated
water
or
DBP
exposure
and
fetal
malformations.
Birth
defects
most
consistently
identified
as
being
associated
with
DBPs
include
neural
tube
defects
and
urinary
tract
malformations.

Other
endpoints
have
also
been
examined
in
recent
epidemiology
studies.
One
study
suggests
an
association
between
DBPs
and
decreased
menstrual
cycle
length
(
Windham
et
al.

2003),
which,
if
corroborated,
could
be
linked
to
the
biological
basis
of
other
reproductive
endpoints
observed.
No
association
between
THM
exposure
and
semen
quality
was
found
(
Fenster
et
al.
2003).
More
work
is
needed
in
both
areas
to
support
these
results.

Reviews.
Epidemiological
reviews
have
progressively
offered
more
support
for
a
possible
association
between
various
reproductive
and
developmental
effects
and
chlorinated
water
or
DBPs.
An
early
review
supported
an
association
between
measures
of
fetal
viability
and
tap
water
(
Swan
et
al.
1992).
Three
other
reviews
found
data
inadequate
to
support
an
association
between
reproductive
and
developmental
health
effects
and
THM
exposure
(
Reif
et
al.
1996;

Craun
1998;
WHO
2000).
Mills
et
al.
(
1998)
examined
data
on
and
found
support
for
an
association
between
fetal
viability
and
malformations
and
THMs.
Another
review
presented
to
the
Stage
2
MDBP
FACA
found
some
evidence
for
an
association
with
fetal
viability
and
some
fetal
malformations
and
exposure
to
DBPs
but
reported
that
the
evidence
was
inconsistent
for
these
endpoints
as
well
as
for
fetal
growth
(
Reif
et
al.
2000).
Reif
et
al.
(
2000)
concluded
that
46
the
weight
of
evidence
from
epidemiology
studies
suggests
that
"
DBPs
are
likely
to
be
reproductive
toxicants
in
humans
under
appropriate
exposure
conditions,"
but
from
a
risk
assessment
perspective,
data
are
primarily
at
the
hazard
identification
stage.
Nieuwenhuijsen
et
al.
(
2000)
found
some
evidence
for
an
association
between
fetal
growth
and
THM
exposure
and
concluded
evidence
for
associations
with
other
fetal
endpoints
is
weak
but
gaining
weight.
A
qualitative
review
by
Villanueva
et
al.
(
2001)
found
evidence
generally
supports
a
possible
association
between
reproductive
effects
and
drinking
chlorinated
water.
Graves
et
al.
(
2001)

supports
a
possible
association
for
fetal
growth
but
not
fetal
viability
or
malformations.
More
recently,
Bove
et
al.
(
2002)
examined
and
supported
an
association
between
small
for
gestational
age,
neural
tube
defects
and
spontaneous
abortion
endpoints
and
DBPs.
Following
a
metaanalysis
on
five
malformation
studies,
Hwang
and
Jaakkola
(
2003)
concluded
that
there
was
evidence
which
supported
associations
between
DBPs
and
risk
of
birth
defects,
especially
neural
tube
defects
and
urinary
tract
defects.
47
Table
II.
D­
3.
Summary
of
Reproductive/
Developmental
Epidemiology
Studies.

Author(
s)
Study
Type
Exposure(
s)
Studied
Outcome(
s)

Measured
Findings
Porter
et
al.
2005
Cross­
sectional
study
in
Maryland,

1998­
2002.
Estimated
THM
and
HAA
exposure
during
pregnancy.
Intrauterine
growth
retardation.
No
consistent
association
or
dose­
response
relationship
was
found
between
exposure
to
either
TTHM
or
HAA5
and
intrauterine
growth
retardation.

Results
suggest
an
increased
risk
of
intrauterine
growth
retardation
associated
with
TTHM
and
HAA5
exposure
in
the
third
trimester,
although
only
HAA5
results
were
statistically
significant.

Savitz
et
al.
2005
Population­
based
prospective
cohort
study
in
three
communities
around
the
U.
S.,

2000­
2004.
Estimated
TTHM,
HAA9,

and
TOC
exposures
during
pregnancy.
Indices
examined
included
concentration,
ingested
amount,
exposure
from
showering
and
bathing,
and
an
integration
of
all
exposures
combined.
Early
and
late
pregnancy
loss,

preterm
birth,

small
for
gestational
age,

and
term
birth
weight.
No
association
with
pregnancy
loss
was
seen
when
looking
at
high
exposure
of
TTHM
compared
to
low
exposure
of
TTHM.
When
examining
individual
THMs,
a
statistically
significant
association
was
found
between
bromodichloromethane
(
BDCM)
and
pregnancy
loss.
A
similar,

nonstatistically
significant
association
was
seen
between
dibromochloromethane
(
DBCM)
and
pregnancy
loss.
Some
increased
risk
was
seen
for
losses
at
greater
than
12
weeks'
gestation
for
TTHM,
BDCM,
and
TOX
(
total
organic
halide),
but
most
results
generally
did
not
provide
support
for
an
association.

Preterm
birth
showed
a
small
inverse
relationship
with
DBP
exposure
(
i.
e.

higher
exposures
showed
less
preterm
births),
but
this
association
was
weak.

TTHM
exposure
of
80
ug/
L
was
associated
with
twice
the
risk
for
small
for
gestational
age
during
the
third
trimester
and
was
statistically
significant.

Toledano
et
al.

2005
Large
crosssectional
study
in
England,
1992­

1998.
Linked
mother's
residence
at
time
of
delivery
to
modeled
estimates
of
TTHM
levels
in
water
zones.
Stillbirth,
low
birth
weight.
A
significant
association
between
TTHM
and
risk
of
stillbirth,
low
birth
weight,
and
very
low
birth
weight
was
observed
in
one
of
the
three
regions.

When
all
three
regions
were
combined,
small,
but
non­
significant,
excess
risks
were
found
between
all
three
outcomes
and
TTHM
and
chloroform.

No
associations
were
observed
between
reproductive
risks
and
BDCM
or
total
brominated
THMs.

Dodds
et
al.
2004
(
and
King
et
al.

2005)
Population­
based
case­
control
study
in
Nova
Scotia
and
Eastern
Ontario,

1999­
2001.
Estimated
THM
and
HAA
exposure
at
residence
during
pregnancy.
Linked
water
consumption
and
showering/
bathing
to
THM
exposure.
Stillbirth.
A
statistically
significant
association
was
observed
between
stillbirths
and
exposure
to
total
THM,
BDCM,
and
chloroform.
Associations
were
also
detected
for
metrics,
which
incorporated
water
consumption,
showering
and
bathing
habits.
Elevated
relative
risks
were
observed
for
intermediate
exposures
for
total
HAA
and
DCAA
measures;
TCAA
and
brominated
HAA
exposures
showed
no
association.
No
statistically
significant
associations
or
dose­
response
relationships
between
any
HAAs
and
stillbirth
were
detected
after
controlling
for
THM
exposure.

Infante­
Rivard
2004
Case­
control
study
of
newborns
in
Montreal,
1998­

2000.
Estimated
THM
levels
and
water
consumption
during
pregnancy.
Exposure
from
showering
and
presence
of
two
genetic
Intrauterine
growth
retardation.
No
associations
were
found
between
exposure
to
THMs
and
intrauterine
growth
retardation.
However,
a
significant
effect
was
observed
between
THM
exposure
and
intrauterine
growth
retardation
for
newborns
with
the
CYP2E1
gene
variant.
Findings
suggest
that
exposure
to
THMs
at
the
highest
levels
can
affect
fetal
growth
but
only
in
genetically
susceptible
48
polymorphisms.
newborns.

Wright
et
al.

2004
Large
crosssectional
study:

Massachusetts,

1995­
1998.
Estimated
maternal
thirdtrimester
exposures
to
TTHMs,
chloroform,

BDCM,
total
HAAs,
DCA,

TCA,
MX
and
mutagenicity
in
drinking
water.
Birth
weight,

small
for
gestational
age,

preterm
delivery,

gestational
age.
Statistically
significant
reductions
in
mean
birth
weight
were
observed
for
BDCM,
chloroform,
and
mutagenic
activity.
An
exposure­
response
relationship
was
found
between
THM
exposure
and
reductions
in
mean
birth
weight
and
risk
of
small
for
gestational
age.
There
was
no
association
between
preterm
delivery
and
elevated
levels
of
HAAs,
MX,
or
mutagenicity.
A
reduced
risk
of
preterm
delivery
was
observed
with
high
THM
exposures.
Gestational
age
was
associated
with
exposure
to
THMs
and
mutagenicity.

Yang
et
al.
2004
(
and
Yang
et
al.

2000)
Large
crosssectional
studies
in
Taiwan,
1994­

1996.
Compared
maternal
consumption
of
chlorinated
drinking
water
(
yes/
no).
Low
birth
weight,

preterm
delivery.
Residence
in
area
supplied
with
chlorinated
drinking
water
showed
a
statistically
significant
association
with
preterm
delivery.
No
association
was
seen
between
chlorinated
drinking
water
and
low
birth
weight.

Fenster
et
al.

2003
Small
prospective
study
in
California,
1990­

1991.
Examined
TTHM
levels
within
the
90
days
preceding
semen
collection.
Sperm
motility,

sperm
morphology.
No
association
between
TTHM
level
and
sperm
mobility
or
morphology.

BDCM
was
inversely
associated
with
linearity
of
sperm
motion.
There
was
some
suggestion
that
water
consumption
and
other
ingestion
metrics
may
be
associated
with
different
indicators
of
semen
quality.

Shaw
et
al.
2003
2
case­
control
maternal
interview
studies:
CA,
1987­

1991.
Estimated
THM
levels
for
mothers'
residences
from
before
conception
through
early
pregnancy.
Neural
tube
defects,
oral
clefts,

selected
heart
defects.
No
associations
or
exposure­
response
relation
were
observed
between
malformations
and
TTHMs
in
either
study.

Windham
et
al.

2003
Prospective
study:

CA,
1990­
1991.
Estimated
exposure
to
THMs
through
showering
and
ingestion
over
average
of
5.6
menstrual
cycles
per
woman.
Menstrual
cycle,

follicular
phase
length
(
in
days).
Findings
suggest
that
THM
exposure
may
affect
ovarian
function.
All
brominated
THM
compounds
were
associated
with
significantly
shorter
menstrual
cycles
with
the
strongest
finding
for
chlorodibromomethane.

There
was
little
association
between
TTHM
exposure
and
luteal
phase
length,
menses
length,
or
cycle
variability.

Wright
et
al.

2003
Cross­
sectional
study:
Massachusetts,

1990.
Estimated
TTHM
exposure
in
women
during
pregnancy
(
average
for
pregnancy
and
during
each
trimester).
Birth
weight,

small
for
gestational
age,

preterm
delivery,

gestational
age.
Statistically
significant
associations
between
2nd
trimester
and
pregnancy
average
TTHM
exposure
and
small
for
gestational
age
and
fetal
birth
weight
were
detected.
Small,
statistically
significant
increases
in
gestational
duration/
age
were
observed
at
increased
TTHM
levels,
but
there
was
little
evidence
of
an
association
between
TTHM
and
preterm
delivery
or
low
birth
weight.

Cedergren
et
al.

2002
Retrospective
case­
control
study:

Sweden,
1982­

1997.
Examined
maternal
periconceptional
DBP
levels
and
used
GIS
to
assign
water
supplies.
Cardiac
defects.
Exposure
to
chlorine
dioxide
in
drinking
water
showed
statistical
significance
for
cardiac
defects.
THM
concentrations
of
10
ug/
L
and
higher
were
significantly
associated
with
cardiac
defects.
No
excess
risk
for
cardiac
defect
and
nitrate
were
seen.

Hwang
et
al.

2002
Large
crosssectional
study
in
Norway,
1993­
Compared
exposure
to
chlorination
(
yes/
no)
and
water
color
levels
for
Birth
defects
(
neural
tube
defects,
cardiac,
Risk
of
any
birth
defect,
cardiac,
respiratory
system,
and
urinary
tract
defects
were
significantly
associated
with
water
chlorination.
Exposure
to
chlorinated
drinking
water
was
statistically
significantly
associated
with
risk
49
1998.
mother's
residence
during
pregnancy.
respiratory
system,

oral
cleft,
urinary
tract).
of
ventricular
septal
defects,
and
an
exposure­
response
pattern
was
seen.
No
other
specific
defects
were
associated
with
the
exposures
that
were
examined.

Dodds
and
King
2001
Population­
based
retrospective
cohort
in
Nova
Scotia,
1988­
1995.
Estimated
THM,

chloroform,
and
bromodichloromethane
(
BDCM)
exposure.
Neural
tube
defects,
cardiovascular
defects,
cleft
defects,
chromosomal
abnormalities.
Exposure
to
BDCM
was
associated
with
increased
risk
of
neural
tube
defects,
cardiovascular
anomalies.
Chloroform
was
not
associated
with
neural
tube
defects,
but
was
associated
with
chromosomal
abnormalities.
No
association
between
THM
and
cleft
defects
were
detected.

Jaakkola
et
al.

2001
Large
crosssectional
study
in
Norway,
1993­

1995.
Compared
chlorination
(
yes/
no)
and
water
color
(
high/
low)
for
mother
during
pregnancy.
Low
birth
weight,

small
for
gestational
age,

preterm
delivery.
No
evidence
found
for
association
between
prenatal
exposure
to
chlorinated
drinking
water
and
low
birth
weight
or
small
for
gestational
age.
A
reduced
risk
of
preterm
delivery
was
noted
for
exposure
to
chlorinated
water
with
high
color
content.

Källén
and
Robert
2000
Large
crosssectional
cohort
study
in
Sweden,

1985­
1994.
Linked
prenatal
exposure
to
drinking
water
disinfected
with
various
methods
(
no
chlorine,

chlorine
dioxide
only,

sodium
hypochlorite
only).
Gestational
duration,
birth
weight,
intrauterine
growth,
mortality,

congenital
malformations,

and
other
birth
outcomes.
A
statistically
significant
difference
was
found
for
short
gestational
duration
and
low
birth
weight
among
infants
whose
mother
resided
in
areas
using
sodium
hypochlorite,
but
not
for
chlorine
dioxide.
Sodium
hypochlorite
was
also
associated
with
other
indices
of
fetal
development
but
not
with
congenital
defects.
No
other
effects
were
observed
for
intrauterine
growth,

childhood
cancer,
infant
mortality,
low
Apgar
score,
neonatal
jaundice,
or
neonatal
hypothyroidism
in
relation
to
either
disinfection
method.

Dodds
et
al.
1999
(
and
King
et
al.

2000b)
Population­
based
retrospective
cohort
study
in
Nova
Scotia,

1988­
1995.
Estimated
TTHM
level
for
women
during
pregnancy.
Low
birth
weight,

preterm
birth,

small
for
gestational
age,

stillbirth,
chromosomal
abnormalities,

neural
tube
defects,
cleft
defects,
major
cardiac
defects.
A
statistically
significant
increased
risk
for
stillbirths
and
high
total
THMs
and
specific
THMs
during
pregnancy
was
detected,
with
higher
risks
observed
among
asphyxia­
related
stillbirths.
Bromodichloromethane
had
the
strongest
association
and
exhibited
an
exposure­
response
pattern.
There
was
limited
evidence
of
an
association
between
THM
level
and
other
reproductive
outcomes.
No
congenital
anomalies
were
associated
with
THM
exposure,
except
for
a
non­
statistically
significant
association
with
chromosomal
abnormalities.

Klotz
and
Pyrch
1999
(
and
Klotz
and
Pyrch
1998)
Population­
based
case­
control
study
in
New
Jersey,

1993­
1994.
Estimated
exposure
of
pregnant
mothers
to
TTHMs
and
HAAs,
and
compared
source
of
water.
Neural
tube
defects.
A
significant
association
was
seen
between
exposure
to
THMs
and
neural
tube
defects.
No
associations
were
observed
for
neural
tube
defects
and
haloacetic
acids
or
haloacetonitriles.

Magnus
et
al.

1999
Large
crosssectional
study
in
Compared
chlorination
(
yes/
no)
and
water
color
Birth
defects
(
neural
tube
Statistically
significant
associations
were
seen
between
urinary
tract
defects
and
chlorination
and
high
water
color
(
high
content
of
organic
compounds).
50
Norway,
1993­

1995.
(
high/
low)
at
mothers'

residences
at
time
of
birth.
defects,
major
cardiac,
respiratory,

urinary,
oral
cleft).
No
associations
were
detected
for
other
outcomes
or
all
birth
defects
combined.
A
non­
statistically
significant,
overall
excess
risk
of
birth
defects
was
seen
within
municipalities
with
chlorination
and
high
water
color
compared
to
municipalities
with
no
chlorination
and
low
color.

Gallagher
et
al.

1998
Retrospective
cohort
study
of
newborns
in
Colorado,
1990­

1993.
Estimated
THM
levels
in
drinking
water
during
third
trimester
of
pregnancy.
Low
birth
weight,

term
low
birthweight,
and
preterm
delivery.
Weak,
non­
statistically
significant
association
with
low
birth
weight
and
TTHM
exposure
during
the
third
trimester.
Large
statistically
significant
increase
for
term
low
birthweight
at
highest
THM
exposure
levels.
No
association
between
preterm
delivery
and
THM
exposure.

Swan
et
al.
1998
Prospective
study
in
California,

1990­
1991.
Compared
consumption
of
cold
tap
water
to
bottled
water
during
early
pregnancy.
Spontaneous
abortion.
Pregnant
women
who
drank
cold
tap
water
compared
to
those
who
consumed
no
cold
tap
water
showed
a
significant
finding
for
spontaneous
abortion
at
one
of
three
sites.

Waller
et
al.

1998
(
and
Waller
et
al.
2001)
Prospective
cohort
in
California,

1989­
1991.
Estimated
TTHM
levels
during
first
trimester
of
pregnancy
via
ingestion
and
showering.
Spontaneous
abortion.
Statistically
significant
increased
risk
between
high
intake
of
TTHMs
and
spontaneous
abortion
compared
to
low
intake.
BDCM
statistically
associated
with
increased
spontaneous
abortion;
other
THMs
not.

Reanalysis
of
exposure
yielded
less
exposure
misclassification
and
relative
risks
similar
in
magnitude
to
earlier
study.
An
exposure­
response
relationship
was
seen
between
spontaneous
abortion
and
ingestion
exposure
to
TTHMs.

Kanitz
et
al.

1996
Cross­
sectional
study
in
Italy,

1988­
1989.
Compared
3
types
of
water
treatment
(
chlorine
dioxide,
sodium
hypochlorite,
and
chlorine
dioxide/
sodium
hypochlorite).
Low
birth
weight,

body
length,

cranial
circumference,

preterm
delivery,

and
other
effects.
Smaller
body
length
and
small
cranial
circumference
showed
statistical
significant
association
with
maternal
exposure
to
chlorinated
drinking
water.

Neonatal
jaundice
linked
statistically
to
prenatal
exposure
to
drinking
water
treated
with
chlorine
dioxide.
Length
of
pregnancy,
type
of
delivery,
and
birthweight
showed
no
association.

Bove
et
al.
1995
(
and
Bove
et
al.

1992a
&
1992b)
Large
cohort
cross­
sectional
study
in
New
Jersey,
1985­
1988.
Examined
maternal
exposure
to
TTHM
and
various
other
contaminants.
Low
birth
weight,

fetal
deaths,
small
for
gestational
age,
birth
defects
(
neural
tube
defects,
oral
cleft,

central
nervous
system,
major
cardiac).
Weak,
statistically
significant
increased
risk
found
for
higher
TTHM
levels
with
small
for
gestational
age,
neural
tube
defects,
central
nervous
system
defects,
oral
cleft
defects,
and
major
cardiac
defects.
Some
association
with
higher
TTHM
exposure
and
low
birth
weight.
No
effect
seen
for
preterm
birth,
very
low
birth
weight,
or
fetal
deaths.

Savitz
et
al.
1995
Population­
based
case­
control
study:

North
Carolina,

1988­
1991.
Examined
TTHM
concentration
at
residences
and
water
consumption
(
during
first
and
third
trimesters).
Spontaneous
abortion,
preterm
delivery,
low
birth
weight.
There
was
a
statistically
significant
increased
miscarriage
risk
with
high
THM
concentration,
but
THM
intake
(
based
on
concentration
times
consumption
level)
was
not
related
to
pregnancy
outcome.
No
associations
were
seen
for
preterm
delivery
or
low
birth
weight.
Water
source
was
not
related
to
pregnancy
outcome
either,
with
the
exception
of
a
non­
significant,
51
increased
risk
of
spontaneous
abortion
for
bottled
water
users.
There
was
a
non­
statistically
significant
pattern
of
reduced
risk
with
increased
consumption
of
water
for
all
three
outcomes.

Aschengrau
et
al.

1993
Case­
control
study
in
Massachusetts,

1977­
1980.
Source
of
water
and
2
types
of
water
treatment
(
chlorination,
chloramination).
Neonatal
death,

stillbirth,
congenital
anomalies.
There
was
a
non­
significant,
increased
association
between
frequency
of
stillbirths
and
maternal
exposure
to
chlorinated
versus
chloraminated
surface
water.
An
increased
risk
of
urinary
track
and
respiratory
track
defects
and
chlorinated
water
was
detected.
Neonatal
death
and
other
major
malformations
showed
no
association.
No
increased
risk
seen
for
any
adverse
pregnancy
outcomes
for
surface
water
versus
ground
and
mixed
water
use.

Kramer
et
al.

1992
Population­
based
case­
control
study
in
Iowa,
1989­

1990.
Examined
chloroform,

DCBM,
DBCM,
and
bromoform
levels
and
compared
type
of
water
source
(
surface,
shallow
well,
deep
well).
Low
birth
weight,

prematurity,

intrauterine
growth
retardation.
Statistically
significant
increased
risk
for
intrauterine
growth
retardation
effects
from
chloroform
exposure
were
observed.
Non­
significant
increased
risks
were
observed
for
low
birth
weight
and
chloroform
and
for
intrauterine
growth
retardation
and
DCBM.
No
intrauterine
growth
retardation
or
low
birth
weight
effects
were
seen
for
the
other
THMs,
and
no
effects
on
prematurity
were
observed
for
any
of
the
THMs.

Shaw
et
al.
1991
(
and
Shaw
et
al.

1990)
Small
case­
control
study:
Santa
Clara
County,
CA,
1981­

1983.
Estimated
chlorinated
tap
water
consumption,
mean
maternal
TTHM
level,

showering/
bathing
exposure
at
residence
during
first
trimester.
Congenital
cardiac
anomalies.
Following
reanalysis,
no
association
between
cardiac
anomalies
and
TTHM
level
were
observed.

Aschengrau
et
al.

1989
Case­
control
study
in
Massachusetts,

1976­
1978.
Source
of
water
and
exposure
to
metals
and
other
contaminants.
Spontaneous
abortion.
A
statistically
significantly
association
was
detected
between
surface
water
source
and
frequency
of
spontaneous
abortion.

Reviews/

Metaanalyses
Study
Type
Exposure(
s)
Studied
Outcome(
s)

Measured
Findings
Hwang
and
Jakkola
2003
Review
and
metaanalysis
of
5
studies.
Compared
DBP
levels,

source
of
water,
chlorine
residual,
color
(
high/
low),

and
2
types
of
disinfection:

chlorination
and
chloramination.
Birth
defects
(
respiratory
system,
urinary
system,
neural
tube
defects,

cardiac,
oral
cleft).
The
meta­
analysis
supports
an
association
between
exposure
to
chlorination
by­
products
and
the
risk
of
any
birth
defect,
particularly
the
risk
of
neural
tube
defects
and
urinary
system
defects.

Bove
et
al.
2002
Qualitative
review
of
14
studies.
Examined
THM
levels.

Compared
drinking
water
source
and
type
of
water
treatment.
Birth
defects,

small
for
gestational
age,

low
birth
weight,

preterm
delivery,
Review
found
the
studies
of
THMs
and
adverse
birth
outcomes
provide
moderate
evidence
for
associations
with
small
for
gestational
age,
neural
tube
defects,
and
spontaneous
abortions.
Authors
felt
risks
may
have
been
underestimated
and
exposure­
response
relationships
distorted
due
to
exposure
misclassification.
52
spontaneous
abortion,
fetal
death.

Graves
et
al.

2001
Review
of
toxicological
and
epidemiological
studies
using
a
weight
of
evidence
approach.
Examined
water
consumption,
duration
of
exposure,
THM
levels,

HAA
levels,
and
other
contaminants.
Compared
source
of
water,
water
treatment,
water
color
(
high/
low),
etc.
Low
birth
weight,

preterm
delivery,

small
for
gestational
age,

intrauterine
growth
retardation,

specific
birth
defects,
neonatal
death,
decreased
fertility,
fetal
resorption,
and
other
effects.
Weight
of
evidence
suggested
positive
association
with
DBP
exposure
for
growth
retardation
such
as
small
for
gestational
age
or
intrauterine
growth
retardation
and
urinary
tract
defects.
Review
found
no
support
for
DBP
exposure
and
low
birth
weight,
preterm
delivery,
some
specific
birth
defects,

and
neonatal
death,
and
inconsistent
findings
for
all
birth
defects,
all
central
nervous
system
defects,
neural
tube
defects,
spontaneous
abortion,
and
stillbirth.

Villanueva
et
al.

2001
Qualitative
review
of
14
reproductive
and
developmental
health
effect
studies.
Compared
exposure
to
TTHM
levels,
mutagenic
drinking
water,
water
consumption,
source
water,

types
of
disinfection
(
chlorination
and
chloramination),
and
residence
times.
Spontaneous
abortion,
low
birth
weight,
small
for
gestational
age,

neural
tube
defects,
other
reproductive
and
developmental
outcomes.
Review
found
positive
associations
between
increased
spontaneous
abortion,

low
birth
weight,
small
for
gestational
age,
and
neural
tube
defects
and
drinking
chlorinated
water
in
most
studies,
although
not
always
with
statistical
significance.

Nieuwenhuijsen
et
al.
2000
Qualitative
review
of
numerous
toxicological
and
epidemiological
studies.
Examined
levels
of
various
DBPs,
water
consumption,

and
duration
of
exposure.

Compared
water
color,

water
treatment,
source
of
water,
etc.
Low
birth
weight,

preterm
delivery,

spontaneous
abortions,

stillbirth,
birth
defects,
etc.
The
review
supports
some
evidence
of
association
between
THMs
and
low
birth
weight,
but
inconclusive.
Review
found
no
evidence
of
association
between
THMs
and
preterm
delivery,
and
that
associations
for
other
outcomes
(
spontaneous
abortions,
stillbirth,
and
birth
defects)
were
weak
but
gaining
weight.

Reif
et
al.
2000
Qualitative
reviews
of
numerous
epidemiological
studies.
Compared
source
of
water
supply
and
methods
of
disinfection.
Estimated
TTHM
levels.
Birth
weight,
low
birth
weight,

intrauterine
growth
retardation,
small
for
gestational
age,
preterm
deliver,
somatic
parameters,
Weight
of
evidence
suggested
DBPs
are
reproductive
toxicants
in
humans
under
appropriate
exposure
conditions.
The
review
reports
findings
between
TTHMs
and
effects
on
fetal
growth,
fetal
viability,
and
congenital
anomalies
as
inconsistent.
Reviewers
felt
data
are
at
the
stage
of
hazard
identification
and
did
not
suggest
a
dose­
response
pattern
of
increasing
risk
with
increasing
TTHM
concentration.
53
neonatal
jaundice,

spontaneous
abortion,
stillbirth,

developmental
anomalies.

WHO
2000
Qualitative
reviews
of
various
studies
in
Finland,

U.
S.,
and
Canada.
Various
exposures
to
THMs.
Various
reproductive
and
developmental
effects.
Review
found
some
support
for
an
association
between
increased
risks
of
neural
tube
defects
and
miscarriage
and
THM
exposure.
Other
associations
have
been
observed,
but
the
authors
believed
insufficient
data
exists
to
assess
any
of
these
associations.

Craun,
ed.
1998
Qualitative
review
of
10
studies,

focus
on
California
cohort
study.
Examined
THM
levels
and
water
consumption,
and
compared
source
of
water
and
water
treatment
(
chlorine,
chloramines,

chlorine
dioxide).
Stillbirth,
neonatal
death,
spontaneous
abortion,
low
birth
weight,
preterm
delivery,
intrauterine
growth
retardation,

neonatal
jaundice,

birth
defects.
Associations
between
DBPs
and
various
reproductive
effects
were
seen
in
some
epidemiological
studies,
but
the
authors
felt
these
results
do
not
provide
convincing
evidence
for
a
causal
relationship
between
DBPs
and
reproductive
effects.

Mills
et
al.
1998
Qualitative
review
of
22
studies.
Examined
TTHM
levels
and
water
consumption.

Compared
source
of
water
and
2
types
of
water
treatment
(
chlorination
and
chloramination).
Various
reproductive
and
developmental
effects.
Review
found
studies
suggest
possible
increases
in
adverse
reproductive
and
developmental
effects,
such
as
increased
spontaneous
abortion
rates,
small
for
gestational
age,
and
fetal
anomalies,
but
that
insufficient
evidence
exists
to
establish
a
causal
relationship.

Reif
et
al.
1996
Review
of
3
casecontrol
studies
and
1
cross­
sectional
study.
Examined
THM
levels
at
residences,
dose
consumption,
chloroform.

Compared
source
of
waters
and
2
types
of
water
treatment
(
chlorination
and
chloramination).
Birth
defects
(
central
nervous
system,
neural
tube
defects,

cardiac,
oral
cleft,

respiratory,

urinary
tract),

spontaneous
abortion,
low
birth
weight,
growth
retardation,

preterm
delivery,

intrauterine
growth
retardation,
Studies
reviewed
suggest
that
exposure
to
DBPs
may
increase
intrauterine
growth
retardation,
neural
tube
defects,
major
heart
defects,
and
oral
cleft
defects.
Review
found
epidemiologic
evidence
supporting
associations
between
exposure
to
DBPs
and
adverse
pregnancy
outcomes
to
be
sparse
and
to
provide
an
inadequate
basis
to
identify
DBPs
as
a
reproductive
or
developmental
hazard.
54
stillbirth,
neonatal
death.
Swan
et
al.
1992
Qualitative
review
of
5
studies
in
Santa
Clara
County,
CA
(
Deane
et
al.
1992,
Wrensch
et
al.
1992,
Hertz­
Picciotto
et
al.
1992,
Windham
et
al.
1992,
Fenster
et
al.
1992).
Compared
maternal
consumption
of
residence
tap
water
to
bottled
water.
Spontaneous
abortion.
Four
of
the
studies
reviewed
suggest
that
wom
during
the
first
trimester
of
pregnancy
may
ha
abortion
relative
to
drinking
tap
water.
No
as
Review
concluded
that
if
findings
are
causal
a
data
suggest
a
10­
50%
increase
in
spontaneou
women
drinking
tap
water
over
bottled
water.

ii.
Toxicology.
To
date,
the
majority
of
reproductive
and
developmental
toxicology
studies
have
been
short
term
and
higher
dose.
Many
of
these
studies
are
summarized
in
a
review
by
Tyl
(
2000).
A
summary
of
this
review
and
of
additional
studies
is
provided
in
the
proposed
Stage
2
DBPR
(
USEPA
2003a).
Individual
DBP
supporting
documents
evaluate
and
assess
additional
studies
as
well
(
USEPA
2000b;
USEPA
2000c;
USEPA
2001a;
USEPA
2001b;

USEPA
2003b;
USEPA
2005b;
USEPA
2005c;
USEPA
2005d;
USEPA
2005e;
USEPA
2005lk).

A
number
of
recent
studies
have
been
published
that
include
in
vivo
and
in
vitro
assays
to
address
mechanism
of
action.
Overall,
reproductive
and
developmental
toxicology
studies
indicate
a
possible
reproductive/
developmental
health
hazard
although
they
are
preliminary
in
nature
for
the
majority
of
DBPs,
and
the
dose­
response
characteristics
of
most
DBPs
have
not
been
quantified.

Some
of
the
reproductive
effects
of
DCAA
were
quantified
as
part
of
the
RfD
development
process,
and
impacts
of
DCAA
on
testicular
structure
are
one
of
the
critical
effects
in
the
study
that
is
the
basis
of
the
RfD
(
USEPA
2003b).

A
few
long
term,
lower
dose
studies
have
been
completed.
Christian
et
al.
(
2002a
and
2002b)
looked
for
an
association
between
BDCM
and
DBAA
and
reproductive
and
55
developmental
endpoints.
The
authors
identified
a
NOAEL
and
LOAEL
of
50
ppm
and
150
ppm,

respectively,
based
on
delayed
sexual
maturation
for
BDCM
and
a
NOAEL
and
LOAEL
of
50
ppm
and
250
ppm
based
on
abnormal
spermatogenesis
for
DBAA.
The
authors
concluded
that
similar
effects
in
humans
would
only
be
seen
at
levels
many
orders
of
magnitude
higher
than
that
of
current
drinking
water
levels.
As
discussed
in
more
detail
in
the
proposal,
EPA
believes
that
because
of
key
methodological
differences
indicated
as
being
important
in
other
studies
(
Bielmeier
et
al.
2001;
Bielmeier
et
al.
2004;
Kaydos
et
al.
2004;
Klinefelter
et
al.
2001;
Klinefelter
et
al.

2004),
definitive
conclusions
regarding
BDCM
and
DBAA
cannot
be
drawn.
Other
multigeneration
research
underway
includes
a
study
on
BCAA,
but
this
research
is
not
yet
published.

Biological
plausibility
for
the
effects
observed
in
reproductive
and
developmental
epidemiological
studies
has
been
demonstrated
through
various
toxicological
studies
on
some
individual
DBPs
(
e.
g.,
Bielmeier
et
al.
2001;
Bielmeier
et
al.
2004;
Narotsky
et
al.
1992;
Chen
et
al.
2003;
Chen
et
al.
2004).
Some
of
these
studies
were
conducted
at
high
doses,
but
similarity
of
effects
observed
between
toxicology
studies
and
epidemiology
studies
strengthens
the
weight
of
evidence
for
a
possible
association
between
adverse
reproductive
and
developmental
health
effects
and
exposure
to
chlorinated
surface
water.

c.
Conclusions.
EPA's
weight
of
evidence
evaluation
of
the
best
available
science
on
carcinogenicity
and
reproductive
and
developmental
effects,
in
conjunction
with
the
widespread
exposure
to
DBPs,
supports
the
incremental
regulatory
changes
in
today's
rule
that
target
lowering
DBPs
and
providing
equitable
public
health
protection.

EPA
believes
that
the
cancer
epidemiology
and
toxicology
literature
provide
important
information
that
contributes
to
the
weight
of
evidence
for
potential
health
risks
from
exposure
to
56
chlorinated
drinking
water.
At
this
time,
the
cancer
epidemiology
studies
support
a
potential
association
between
exposure
to
chlorinated
drinking
water
and
cancer,
but
evidence
is
insufficient
to
establish
a
causal
relationship.
The
epidemiological
evidence
for
an
association
between
DBP
exposure
and
colon
and
rectal
cancers
is
not
as
consistent
as
it
is
for
bladder
cancer,
although
similarity
of
effects
reported
in
animal
toxicity
and
human
epidemiology
studies
strengthens
the
evidence
for
an
association
with
colon
and
rectal
cancers.
EPA
believes
that
the
overall
cancer
epidemiology
and
toxicology
data
support
the
decision
to
pursue
additional
DBP
control
measures
as
reflected
in
the
Stage
2
DBPR.

Based
on
the
weight
of
evidence
evaluation
of
the
reproductive
and
developmental
epidemiology
data
EPA
concludes
that
,
EPA
concludes
that
a
causal
link
between
adverse
reproductive
or
developmental
health
effects
and
exposure
to
chlorinated
drinking
water
or
DBPs
has
not
been
established,
but
that
there
is
a
potential
association
between
DBPs
and
adverse
reproductive
and
developmental
effects.
Despite
inconsistent
findings
across
studies,
some
recent
studies
using
stronger
methods
and
study
design
continue
to
suggest
associations
between
DBP
exposure
and
various
adverse
reproductive
and
developmental
effects.
In
addition,
data
from
a
number
of
toxicology
studies,
although
the
majority
of
them
were
conducted
using
high
doses,

indicate
a
health
hazard
and
demonstrate
biological
plausibility
for
some
of
the
effects
observed
in
epidemiology
studies.
NEPA
concludes
that
no
dose­
response
relationship
or
causal
link
has
been
established
between
exposure
to
chlorinated
drinking
water
or
disinfection
byproducts
and
adverse
developmental
or
reproductive
health
effects.
EPA's
evaluation
of
the
best
available
studies,
particularly
epidemiology
studies
is
that
they
do
not
support
a
conclusion
at
this
time
as
to
whether
exposure
to
chlorinated
drinking
water
or
disinfection
byproducts
causes
adverse
57
developmental
and
reproductive
health
effects,
but
do
provides
an
indication
of
a
potential
health
hazardconcern
that
warrants
incremental
regulatory
action
beyond
the
Stage
1
DBPR.

D.
DBP
Occurrence
and
DBP
Control
New
information
on
the
occurrence
of
DBPs
in
distribution
systems
raises
issues
about
the
protection
provided
by
the
Stage
1
DBPR.
This
section
presents
new
occurrence
and
treatment
information
used
to
identify
key
issues
and
to
support
the
development
of
the
Stage
2
DBPR.
For
a
more
detailed
discussion
see
the
proposed
Stage
2
DBPR
(
USEPA
2003a).
For
additional
information
on
occurrence
of
regulated
and
nonregulated
DBPs,
see
the
Stage
2
Occurrence
Assessment
for
the
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
(
USEPA
2005f).

1.
Occurrence
EPA,
along
with
the
M­
DBP
Advisory
Committee,
collected,
developed,
and
evaluated
new
information
that
became
available
after
the
Stage
1
DBPR
was
published.
The
Information
Collection
Rule
(
ICR)
(
USEPA
1996)
provided
new
field
data
on
DBP
exposure
for
large
water
systems
and
new
study
data
on
the
effectiveness
of
several
DBP
control
technologies.
The
unprecedented
amount
of
information
collected
under
the
ICR
was
supplemented
by
a
survey
conducted
by
the
National
Rural
Water
Association,
data
provided
by
various
States,
the
Water
Utility
Database
(
which
contains
data
collected
by
the
American
Water
Works
Association),
and
ICR
Supplemental
Surveys
for
small
and
medium
water
systems.

After
analyzing
the
DBP
occurrence
data,
EPA
and
the
Advisory
Committee
reached
three
significant
conclusions
that
in
part
led
the
Advisory
Committee
to
recommend
further
control
of
58
DBPs
in
public
water
systems.
First,
the
data
from
the
Information
Collection
Rule
showed
that
the
RAA
compliance
calculation
under
the
Stage
1
DBPR
allows
elevated
TTHM
or
HAA5
levels
to
regularly
occur
at
some
locations
in
the
distribution
system
while
the
overall
average
of
TTHM
or
HAA5
levels
at
all
DBP
monitoring
locations
is
below
the
MCLs
of
the
Stage
1
DBPR.

Customers
served
at
those
sampling
locations
with
DBP
levels
that
are
regularly
above
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5
experience
higher
exposure
compared
to
customers
served
at
locations
where
these
levels
are
consistently
met.

Second,
the
new
data
demonstrated
that
DBP
levels
in
single
samples
can
be
substantially
above
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5.
Some
customers
receive
drinking
water
with
concentrations
of
TTHM
and
HAA5
up
to
75%
above
0.080
mg/
L
and
0.060
mg/
L,
respectively,

even
when
their
water
system
is
in
compliance
with
the
Stage
1
DBPR.
Some
studies
support
an
association
between
acute
exposure
to
DBPs
and
potential
adverse
reproductive
and
developmental
health
effects
(
see
Section
III.
C
for
more
detail).

Third,
the
data
from
the
Information
Collection
Rule
revealed
that
the
highest
TTHM
and
HAA5
levels
can
occur
at
any
monitoring
site
in
the
distribution
system.
In
fact,
the
highest
concentrations
did
not
occur
at
the
maximum
residence
time
locations
in
more
than
50%
of
all
ICR
samples.
The
fact
that
the
locations
with
the
highest
DBP
levels
vary
in
different
public
water
systems
indicates
that
the
Stage
1
DBPR
monitoring
may
not
accurately
represent
the
high
DBP
concentrations
that
actually
exist
in
distribution
systems,
and
that
additional
monitoring
is
needed
to
identify
distribution
system
locations
with
elevated
DBP
levels.

These
data
showed
that
efforts
beyond
the
Stage
1
DBPR
are
needed
to
provide
more
equitable
protection
from
DBP
exposure
across
the
entire
distribution
system.
The
incremental
59
regulatory
changes
made
under
the
Stage
2
DBPR
meet
this
need
by
reevaluating
the
locations
of
DBP
monitoring
sites
and
addressing
high
DBP
concentrations
that
occur
at
particular
locations
or
in
single
samples
within
systems
in
compliance.

2.
Treatment
The
analysis
of
the
new
treatment
study
data
confirmed
that
certain
technologies
are
effective
at
reducing
DBP
concentrations.
Bench­
and
pilot­
scale
studies
for
granular
activated
carbon
(
GAC)
and
membrane
technologies
required
by
the
Information
Collection
Rule
provided
information
on
the
effectiveness
of
the
two
technologies.
Other
studies
found
UV
light
to
be
highly
effective
for
inactivating
Cryptosporidium
and
Giardia
at
low
doses
without
promoting
the
formation
of
DBPs
(
Malley
et
al.
1996;
Zheng
et
al.
1999).
This
new
treatment
information
adds
to
the
treatment
options
available
to
utilities
for
controlling
DBPs
beyond
the
requirements
of
the
Stage
1
DBPR.

E.
Conclusions
for
Regulatory
Action
After
extensive
analysis
of
available
data
and
rule
options
considered
by
the
Advisory
Committee
and
review
of
public
comments
on
the
proposed
Stage
2
DBPR
(
USEPA,
2003a),

EPA
is
finalizing
a
Stage
2
DBPR
control
strategy
consistent
with
the
key
elements
of
the
Agreement
in
Principle
signed
in
September
2000
by
the
participants
in
the
Stage
2
M­
DBP
Advisory
Committee.
EPA
believes
that
exposure
to
chlorinated
drinking
water
may
be
associated
with
cancer,
reproductive,
and
developmental
health
risks.
EPA
determined
that
the
risk­
targeting
measures
recommended
in
the
Agreement
in
Principle
will
require
only
those
systems
with
the
greatest
risk
to
make
treatment
and
operational
changes
and
will
maintain
60
simultaneous
protection
from
potential
health
concerns
from
DBPs
and
microbial
contaminants.

EPA
has
carefully
evaluated
and
expanded
upon
the
recommendations
of
the
Advisory
Committee
and
public
comments
to
develop
today's
rule.
EPA
also
made
simplifications
where
possible
to
minimize
complications
for
public
water
systems
as
they
transition
to
compliance
with
the
Stage
2
DBPR
while
expanding
public
health
protection.
The
requirements
of
the
Stage
2
DBPR
are
described
in
detail
in
Section
IV
of
this
preamble.

IV.
Explanation
of
Today's
Action
A.
MCLGs
MCLGs
are
set
at
concentration
levels
at
which
no
known
or
anticipated
adverse
health
effects
occur,
allowing
for
an
adequate
margin
of
safety.
Establishment
of
an
MCLG
for
each
specific
contaminant
is
based
on
the
available
evidence
of
carcinogenicity
or
noncancer
adverse
health
effects
from
drinking
water
exposure
using
EPA's
guidelines
for
risk
assessment.
MCLGs
are
developed
to
ensure
they
are
protective
of
the
entire
population.

Today's
rule
provides
MCLGs
for
chloroform
and
two
haloacetic
acids,

monochloroacetic
acid
(
MCAA)
and
trichloroacetic
acid
(
TCAA).

1.
Chloroform
MCLG
a.
Today's
rule.
The
final
MCLG
for
chloroform
is
0.07
mg/
L.
The
MCLG
was
calculated
using
toxicological
evidence
that
the
carcinogenic
effects
of
chloroform
are
due
to
sustained
tissue
toxicity.
EPA
is
not
changing
the
other
THM
MCLGs
finalized
in
the
Stage
1
DBPR.

b.
Background
and
analysis.
The
MCLG
for
chloroform
is
unchanged
from
the
proposal.
61
The
MCLG
is
calculated
using
a
reference
dose
(
RfD)
of
0.01
mg/
kg/
day
and
an
adult
tap
water
consumption
of
2
L
per
day
for
a
70
kg
adult.
A
relative
source
contribution
(
RSC)
of
20%
was
used
in
accordance
with
Office
of
Water's
current
approach
for
deriving
RSC
through
consideration
of
data
that
indicate
that
other
routes
and
sources
of
exposure
may
potentially
contribute
substantially
to
the
overall
exposure
to
chloroform.
See
the
proposed
Stage
2
DBPR
(
USEPA
2003a)
for
a
detailed
discussion
of
the
chloroform
MCLG.

MCLG
for
Chloroform
=
(
0.01
mg/
kg/
day)(
70
kg)(
0.2)
=
0.07
mg/
L
(
rounded)

2L/
day2
L/
day
Based
on
an
analysis
of
the
available
scientific
data
on
chloroform,
EPA
believes
that
the
chloroform
dose­
response
is
nonlinear
and
that
chloroform
is
likely
to
be
carcinogenic
only
under
high
exposure
conditions
(
USEPA
2001a).
This
assessment
is
supported
by
the
principles
of
the
1999
EPA
Proposed
Guidelines
for
Carcinogen
Risk
Assessment
(
USEPA
1999a)
and
reconfirmed
by
the
2005
final
Cancer
Guidelines
(
USEPA
2005ji).
The
science
in
support
of
a
nonlinear
approach
for
estimating
the
carcinogenicity
of
chloroform
was
affirmed
by
the
Chloroform
Risk
Assessment
Review
Subcommittee
of
the
EPA
SAB
Executive
Committee
(
USEPA
2000d).
Since
the
nonzero
MCLG
is
based
on
a
mode
of
action
consideration
specific
to
chloroform,
it
does
not
affect
the
MCLGs
of
other
trihalomethanes.

c.
Summary
of
major
comments.
EPA
received
many
comments
in
support
of
the
proposed
MCLG
calculation
for
chloroform,
although
some
commenters
disagreed
with
a
nonzero
MCLG.

At
this
time,
based
on
an
analysis
of
all
the
available
scientific
data
on
chloroform,
EPA
concludes
that
chloroform
is
likely
to
be
carcinogenic
to
humans
only
under
high
exposure
62
conditions
that
lead
to
cytotoxicity
and
regenerative
hyperplasia
and
that
chloroform
is
not
likely
to
be
carcinogenic
to
humans
under
conditions
that
do
not
cause
cytotoxicity
and
cell
regeneration
(
USEPA
2001a).
Therefore,
the
dose­
response
is
nonlinear,
and
the
MCLG
is
set
at
0.07
mg/
L.
This
conclusion
has
been
reviewed
by
the
SAB
(
USEPA
2000d),
who
agree
that
nonlinear
approach
is
most
appropriate
for
the
risk
assessment
of
chloroform;
it
also
remains
consistent
with
the
principles
of
the
1999
EPA
Proposed
Guidelines
for
Carcinogenic
Risk
Assessment
(
USEPA
1999a)
and
the
final
Cancer
Guidelines
(
USEPA
2005ji),
which
allow
for
nonlinear
extrapolation.

EPA
also
received
some
comments
requesting
a
combined
MCLG
for
THMs
or
HAAs.

This
is
not
appropriate
because
these
different
chemicals
have
different
health
effects.

2.
HAA
MCLGs:
TCAA
and
MCAA
a.
Today's
rule.
Today's
rule
finalizes
the
proposed
Stage
2
MCLG
for
TCAA
of
0.02
mg/
L
(
USEPA
2003a)
and
sets
an
MCLG
for
MCAA
of
0.07
mg/
L.
EPA
is
not
changing
the
other
HAA
MCLGs
finalized
in
the
Stage
1
DBPR
(
USEPA
1998a).

b.
Background
and
analysis.
The
Stage
1
DBPR
included
an
MCLG
for
TCAA
of
0.03
mg/
L
and
did
not
include
an
MCLG
for
MCAA
(
USEPA
1998a).
Based
on
toxicological
data
published
after
the
Stage
1
DBPR,
EPA
proposed
new
MCLGs
for
TCAA
and
MCAA
of
0.02
mg/
L
and
0.03
mg/
L,
respectively,
in
the
Stage
2
proposal
(
USEPA
2003a).
The
proposed
TCAA
MCLG
and
its
supporting
analysis
is
being
finalized
unchanged
in
today's
final
rule.
The
MCLG
calculation
for
MCAA
is
revised
in
this
final
rule,
based
on
a
new
reference
dose,
as
discussed
later.
See
the
proposed
Stage
2
DBPR
(
USEPA
2003a)
for
a
detailed
discussion
of
the
calculation
of
the
MCLGs.
63
TCAA.
The
MCLG
for
TCAA
was
calculated
based
on
the
RfD
of
0.03
mg/
kg/
day
using
a
70
kg
adult
body
weight,
a
2L/
day2
L/
day
drinking
water
intake,
and
a
relative
source
contribution
of
20%.

MCLG
for
TCAA
=
(
0.03
mg/
kg/
day)(
70
kg)(
0.2)
=
0.02
mg/
L
(
rounded)

(
2
L/
day)(
10)

An
additional
tenfold
risk
management
factor
has
been
applied
to
account
for
the
possible
carcinogenicity
of
TCAA.
This
approach
in
accordances
consistent
with
EPA
policy.
TCAA
induces
liver
tumors
in
mice
(
Ferreira­
Gonzalez
et
al.
1995;
Pereira
1996;
Pereira
and
Phelps
1996;
Tao
et
al.
1996;
Latendresse
and
Pereira
1997;
Pereira
et
al.
1997)
but
not
in
rats
(
DeAngelo
et
al.
1997).
Much
of
the
recent
data
on
the
carcinogenicity
of
TCAA
hasve
focused
on
examining
the
carcinogenic
mode(
s)
of
action.
However,
at
this
time,
neither
the
bioassay
nor
the
mechanistic
data
are
sufficient
to
support
the
development
of
a
slope
factor
from
which
to
quantify
the
cancer
risk.

MCLG
for
TCAA
=
(
0.03
mg/
kg/
day)(
70
kg)(
0.2)
=
0.02
mg/
L
(
rounded)

(
2
L/
day)(
10)

The
chronic
bioassay
for
TCAA
by
DeAngelo
et
al.
(
1997)
was
selected
as
the
critical
study
for
the
development
of
the
RfD.
In
this
chronic
drinking
water
study,
a
dose­
response
was
noted
for
several
endpoints
and
both
a
LOAEL
and
NOAEL
were
determined.
The
data
are
64
consistent
with
the
findings
in
both
the
Pereira
(
1996)
chronic
drinking
water
study
and
the
Mather
et
al.
(
1990)
subchronic
drinking
water
study.
The
RfD
of
0.03
mg/
kg/
day
is
based
on
the
NOAEL
of
32.5
mg/
kg/
day
for
liver
histopathological
changes
in
rats
(
DeAngelo
et
al.
1997).

A
composite
uncertainty
factor
of
1000
was
applied
in
the
RfD
determination.
A
default
uncertainty
factor
of
10
was
applied
to
the
RfD
to
account
for
extrapolation
from
an
animal
study
because
data
to
quantify
rat­
to­
human
differences
in
toxicokinetics
or
toxicodynamics
are
not
available.
The
default
uncertainty
factor
of
10
was
used
to
account
for
human
variability
in
the
absence
of
data
on
differences
in
human
susceptibility.
Although
subchronic
and
chronic
studies
of
TCAA
have
been
reported
for
multiple
species,
many
studies
have
focused
on
liver
lesions
and
a
full
evaluation
of
a
wide
range
of
potential
target
organs
has
not
been
conducted
in
two
different
species.
In
addition,
there
has
been
no
multi­
generation
study
of
reproductive
toxicity
and
the
data
from
teratology
studies
in
rats
provide
LOAEL
values
but
no
NOAEL
for
developmental
toxicity.
Thus,
an
additional
uncertainty
factor
of
10
was
used
to
account
for
database
insufficiencies.

The
MCLG
calculation
also
includes
a
relative
source
contribution
(
RSC)
of
20%.
The
RSC
was
derived
consistent
with
Office
of
Water's
current
approach
for
deriving
RSC.
In
addition
to
disinfected
water,
foods
are
expected
to
contribute
to
daily
exposure
to
TCAA
(
Raymer
et
al.
2001,
20034;
Reimann
et
al.
1996).
Some
of
the
TCAA
in
foods
comes
from
cleaning
and
cooking
foods
in
chlorinated
water.
Additional
TCAA
is
found
in
some
foods
because
of
the
wide
spreadwidespread
use
of
chlorine
as
a
sanitizing
agent
in
the
food
industry
(
USFDA
1994).
EPA
was
not
able
to
identify
any
dietary
surveys
or
duplicate
diet
studies
of
TCAA
in
the
diet.
TCAA
also
has
been
identified
in
rain
water,
suggesting
some
presence
in
the
65
atmosphere
(
Reimann
et
al.
1996);
however,
due
to
the
low
volatility
(
0.5
­
0.7
mm
Hg
at
25o
C)

of
TCAA,
exposure
from
ambient
air
is
expected
to
be
minimal.
Dermal
exposure
to
disinfected
water
is
also
unlikely
to
be
significant.
A
study
by
Xu
et
al.
(
2002)
reports
that
dermal
exposure
from
bathing
and
showering
is
only
0.01%
of
that
from
oral
exposure.
In
addition,
the
solvents
trichloroethylene,
tetrachlorethylene,
1,1,1­
trichloroethane
(
often
found
in
ambient
air
and
drinking
water),
and
the
disinfection
byproduct
chloral
hydrate
all
contribute
to
the
body's
TCAA
load
since
each
of
these
compounds
is
metabolized
to
TCAA
(
ATSDR
2004;
ATSDR
1997a;

ATSDR
1997b;
USEPA
2000fe).
Due
to
the
limitations
primarily
in
the
dietary
data
and
a
clear
indication
of
exposure
from
other
sources,
EPA
applied
the
minimum
default
(
a
relative
source
contribution
of
20%).

MCAA.
The
MCLG
for
MCAA
uses
the
following
calculations:
an
RfD
of
0.01
mg/
kg/
day,
a
70
kg
adult
consuming
2
L/
day
of
tap
water,
and
a
relative
source
contribution
of
20%.

The
RfD
included
in
the
proposal
was
based
on
a
chronic
drinking
water
study
in
rats
conducted
by
DeAngelo
et
al.
(
1997).
In
the
assessment
presented
for
the
proposed
rule,
the
LOAEL
from
this
study
was
identified
as
3.5
mg/
kg/
day
based
on
increased
absolute
and
relative
spleen
weight
in
the
absence
of
histopathologic
changes.
After
reviewing
comments
and
further
analysis
of
the
data,
EPA
concludes
that
it
is
more
appropriate
to
identify
this
change
as
a
NOAEL.
Increased
spleen
weights
in
the
absence
of
histopathological
effects
are
not
necessarily
adverse.
In
addition,
spleen
weights
were
decreased,
rather
than
increased
in
the
mid­
and
highdose
groups
in
the
DeAngelo
et
al.
(
1997)
study
and
were
accompanied
by
a
significant
decrease
in
body
weight,
decreased
relative
and
absolute
liver
weights,
decreased
absolute
kidney
weight,
66
and
an
increase
in
relative
testes
weight.
Accordingly,
the
mid­
dose
in
this
same
study
(
26.1
mg/
kg/
day)
has
been
categorized
as
the
LOAEL
with
the
lower
3.5
mg/
kg/
day
dose
as
a
NOAEL.

Based
on
a
NOAEL
of
3.5
mg/
kg/
day
(
DeAngelo
et
al.
1997),
the
revised
RfD
was
calculated
as
shown
below,
with
a
composite
uncertainty
factor
of
300.
EPA
used
a
default
uncertainty
factor
of
10
to
account
for
extrapolation
from
an
animal
study,
since
no
data
on
ratto
human
differences
in
toxicokinetics
or
toxicodynamics
were
identified.
A
default
uncertainty
factor
of
10
was
used
to
account
for
human
variability
in
the
absence
of
data
on
the
variability
in
the
toxicokinetics
of
MCAA
in
humans
or
in
human
susceptibility
to
MCAA.
An
additional
uncertainty
factor
of
three
was
used
to
account
for
database
insufficiencies.
Although
there
is
no
multi­
generation
reproduction
study,
the
available
studies
of
reproductive
and
developmental
processes
suggest
that
developmental
toxicity
is
unlikely
to
be
the
most
sensitive
endpoint.
This
led
to
the
following
calculation
of
the
Reference
Dose
(
RfD)
and
MCLG
for
MCAA:

RfD
=
(
3.5
mg/
kg/
day)
=
0.012
mg/
kg/
day
rounded
to
0.01
mg/
kg/
day
(
300)

where:

3.5
mg/
kg/
day
=
NOAEL
for
decreased
body
weight
plus
decreased
liver,
kidney
and
spleen
weights
in
rats
exposed
to
MCA
for
104
weeks
in
drinking
water
(
DeAngelo
et
al.
1997).

300
=
composite
uncertainty
factor
chosen
to
account
for
inter
species
extrapolation,
inter­
individual
variability
in
humans,
and
deficiencies
in
the
database.

MCLG
for
MCAA
=
(
0.01mg/
kg/
day)(
70
kg)(
0.2)
=
0.07
mg/
L
67
2L/
day2
L/
day
The
RSC
for
MCAA
was
selected
using
comparable
data
to
that
discussed
for
TCAA.

MCAA,
like
TCAA,
has
been
found
in
foods
and
is
taken
up
by
foods
during
cooking
(
15%
in
chicken
to
62%
in
pinto
beans)
and
cleaning
(
2.5%
for
lettuce)
with
water
containing
500
ppb
MCAA
(
Reimann
et
al.
1996;
Raymer
et
al.
2001,
20034).
Rinsing
of
cooked
foods
did
not
increase
the
MCAA
content
of
foods
to
the
same
extent
as
was
observed
for
TCAA
(
Raymer
et
al.
20034).
MCAA
was
found
to
be
completely
stable
in
water
boiled
for
60
minutes
and
is
likely
to
be
found
in
the
diet
due
to
the
use
of
chlorinated
water
in
food
preparation
and
the
use
of
chlorine
as
a
sanitizing
agent
by
the
food
industry
(
USFDA
1994).
As
with
TCAA,
inhalation
and
dermal
exposures
are
unlikely
to
be
significant.
Dermal
exposure
from
bathing
and
showering
was
estimated
to
contribute
only
0.03%
of
that
from
oral
exposure
(
Xu
et
al.
2002).
As
with
TCAA,
due
to
the
limitations
in
dietary
data
and
a
clear
indication
of
exposure
from
other
sources,
EPA
applied
the
minimum
default
(
a
relative
source
contribution
of
20%).

c.
Summary
of
major
comments.
EPA
received
few
comments
on
MCAA
and
TCAA.

The
majority
of
comments
about
the
MCLGs
for
TCAA
and
MCAA
were
general
MCLG
questions,
including
RSC
derivation.
Some
commenters
questioned
why
MCAA,
TCAA,
and
chloroform
were
calculated
using
an
RSC
of
20%.
In
particular,
some
commenters
compared
these
calculations
to
that
for
DBCM
in
the
Stage
1
DBPR,
which
uses
80%.
Each
of
the
MCLGs
set
for
chloroform,
TCAA,
and
MCAA
under
this
rule
is
calculated
using
the
best
available
science
and
EPA
Office
of
Water's
current
approach
for
deriving
the
RSC.
Even
though
the
minimum
defaultEPA
chose
an
RSC
of
20%
was
used
for
each,
not
80%,
because
of
clear
indications
of
exposure
from
other
sources,;
data
limitations
preclude
the
derivation
of
a
specific
68
RSC.

The
RSC
for
DBCM
was
calculated
using
a
different
approach
than
Office
of
Water's
current
approach
for
deriving
RSC80%
in
the
Stage
1
DBPR.
The
DBCM
MCLG
is
not
part
of
today's
rulemaking.
Any
possible
future
revision
to
the
DBCM
MCLG
as
a
result
of
an
RSC
change
would
not
affect
the
MCL
for
TTHM
finalized
in
today's
rule.

In
response
to
comments
received
on
the
RfD
for
MCAA,
EPA
has
reviewed
the
critical
study
regarding
the
appropriateness
of
an
increase
in
spleen
weight
in
the
absence
of
histopathology
as
a
LOAEL.
EPA
has
determined
that
the
dose
associated
with
this
endpoint
is
more
appropriately
categorized
as
a
NOAEL
rather
than
a
LOAEL
and
has
revised
the
RfD
and
MCLG
for
MCAA.

B.
Consecutive
Systems
Today's
rule
includes
provisions
for
consecutive
systems,
which
are
public
water
systems
that
purchase
or
otherwise
receive
some
or
all
of
their
finished
water
from
another
water
system
(
a
wholesale
system).
Consecutive
systems
face
particular
challenges
in
providing
water
that
meets
regulatory
standards
for
DBPs
and
other
contaminants
whose
concentration
can
increase
in
the
distribution
system.
Moreover,
previous
regulation
of
DBP
levels
in
consecutive
systems
varies
widely
among
States.
In
consideration
of
these
factors,
EPA
is
finalizing
monitoring,

compliance
schedule,
and
other
requirements
specifically
for
consecutive
systems.
These
requirements
are
intended
to
facilitate
compliance
by
consecutive
systems
with
MCLs
for
TTHM
and
HAA5
under
the
Stage
2
DBPR
and
help
to
ensure
that
consumers
in
consecutive
systems
receive
equivalent
public
health
protection.
69
1.
Today's
Rule
As
public
water
systems,
consecutive
systems
must
provide
water
that
meets
the
MCLs
for
TTHM
and
HAA5
under
the
Stage
2
DBPR,
use
specified
analytical
methods,
and
must
carry
out
associated
monitoring,
reporting,
recordkeeping,
public
notification,
and
other
requirements.

The
following
discusses
a
series
of
definitions
needed
for
addressing
consecutive
system
requirements
in
today's
rule.
Later
sections
of
this
preamble
provide
further
details
on
how
rule
requirements
(
e.
g.,
schedule
and
monitoring)
apply
to
consecutive
systems.

A
consecutive
system
is
a
public
water
system
that
receives
some
or
all
of
its
finished
water
from
one
or
more
wholesale
systems.

Finished
water
is
water
that
has
been
introduced
into
the
distribution
system
of
a
public
water
system
and
is
intended
for
distribution
and
consumption
without
further
treatment,
except
as
necessary
to
maintain
water
quality
in
the
distribution
system
(
e.
g.,
booster
disinfection,

addition
of
corrosion
control
chemicals).

A
wholesale
system
is
a
public
water
system
that
treats
source
water
as
necessary
to
produce
finished
water
and
then
delivers
finished
water
to
another
public
water
system.
Delivery
may
be
through
a
direct
connection
or
through
the
distribution
system
of
anotherone
or
more
consecutive
systems.

The
combined
distribution
system
is
defined
as
the
interconnected
distribution
system
consisting
of
the
distribution
systems
of
wholesale
systems
and
of
the
consecutive
systems
that
receive
finished
water
from
those
wholesale
system(
s).

EPA
is
allowing
States
some
flexibility
in
defining
what
systems
are
a
part
of
a
combined
dsitributiondistribution
system.
This
provision
determines
effective
dates
for
requirements
in
70
today's
rule;
see
Section
IV.
E
(
Compliance
Schedules)
for
further
discussion.
EPA
has
consulted
with
States
and
deferred
to
their
expertise
regarding
the
nature
of
the
connection
in
making
combined
distribution
system
determinations.
In
the
absence
of
informationinput
from
the
State,
EPA
will
determine
that
combined
distribution
systems
include
all
interconnected
systems
for
the
purpose
of
determining
compliance
schedules
for
implementation
of
this
rule.

2.
Background
and
analysis
The
practice
of
public
water
systems
buying
and
selling
water
to
each
other
has
been
commonplace
for
many
years.
Reasons
include
saving
money
on
pumping,
treatment,
equipment,

and
personnel;
assuring
an
adequate
supply
during
peak
demand
periods;
acquiring
emergency
supplies;
selling
surplus
supplies;
and
delivering
a
better
product
to
consumers.
EPA
estimates
that
there
are
more
than
10,000
consecutive
systems
nationally.

Consecutive
systems
face
particular
challenges
in
providing
water
that
meets
regulatory
standards
for
contaminants
that
can
increase
in
the
distribution
system.
Examples
of
such
contaminants
include
coliforms,
which
can
grow
if
favorable
conditions
exist,
and
some
DBPs,

including
THMs
and
HAAs,
which
can
increase
when
a
disinfectant
and
DBP
precursors
continue
to
react
in
the
distribution
system.

EPA
included
requirements
specifically
for
consecutive
systems
because
States
have
taken
widely
varying
approaches
to
regulating
DBPs
in
consecutive
systems
in
previous
rules.
For
example,
some
States
have
not
regulated
DBP
levels
in
consecutive
systems
that
deliver
disinfected
water
but
do
not
add
a
disinfectant.
Other
States
have
determined
compliance
with
DBP
standards
based
on
the
combined
distribution
system
that
includes
both
the
wholesaler
and
consecutive
systems.
In
this
case,
sites
in
consecutive
systems
are
treated
as
monitoring
sites
71
within
the
combined
distribution
system.
Neither
of
these
approaches
provide
the
same
level
of
public
health
protection
as
non­
consecutive
systems
receive
under
the
Stage
1
DBPR.
Once
fully
implemented,
today's
rule
will
ensure
similar
protection
for
consumers
in
consecutive
systems.

In
developing
its
recommendations,
the
Stage
2
M­
DBP
Advisory
Committee
recognized
two
principles
related
to
consecutive
systems:
(
1)
consumers
in
consecutive
systems
should
be
just
as
well
protected
as
customers
of
all
systems,
and
(
2)
monitoring
provisions
should
be
tailored
to
meet
the
first
principle.
Accordingly,
the
Advisory
Committee
recommended
that
all
wholesale
and
consecutive
systems
comply
with
provisions
of
the
Stage
2
DBPR
on
the
same
schedule
required
of
the
wholesale
or
consecutive
system
serving
the
largest
population
in
the
combined
distribution
system.
In
addition,
the
Advisory
Committee
recommended
that
EPA
solicit
comments
on
issues
related
to
consecutive
systems
that
the
Advisory
Committee
had
not
fully
explored
(
USEPA
2000a).
EPA
agreed
with
these
recommendations
and
they
are
reflected
in
today's
rule.

3.
Summary
of
major
comments
Commenters
generally
supported
the
proposed
definitions.
However,
commenters
did
express
some
concerns,
especially
with
including
a
time
period
of
water
delivery
that
defined
whether
a
system
was
a
consecutive
system
(
proposed
to
trigger
plant­
based
monitoring
requirements)
or
wholesale
system
(
proposed
to
allow
determination
that
a
combined
distribution
system
existed).
EPA
has
dropped
this
requirement
from
the
final
rule;
population­
based
monitoring
requirements
in
the
final
rule
do
not
need
to
define
how
long
a
plant
must
operate
in
order
to
be
considered
a
plant
(
as
was
required
under
the
proposed
plant­
based
monitoring
requirements),
and
EPA
has
provided
some
flexibility
for
States
to
determine
which
systems
72
comprise
a
combined
distribution
system
(
without
presenting
a
time
criterion).

Other
commenters
expressed
concern
that
the
proposed
definition
of
consecutive
system
was
inconsistent
with
use
of
the
term
prior
to
the
rulemaking.
EPA
acknowledges
that
the
Agency
has
not
previously
formally
defined
the
term,
but
believes
that
the
definition
in
today's
rule
best
considers
all
commenters'
concerns,
while
also
providing
for
accountability
and
public
health
protection
in
as
simple
a
manner
as
is
possible
given
the
many
consecutive
system
scenarios
that
currently
exist.

Several
States
requested
flexibility
to
determine
which
systems
comprised
a
combined
distribution
system
under
this
rule;
EPA
has
included
that
flexibility
for
situations
in
which
systems
have
only
a
marginal
association
(
such
as
an
infrequently
used
emergency
connection)

with
other
systems
in
the
combined
distribution
system.
To
prepare
for
the
IDSE
and
subsequent
Stage
2
implementation,
EPA
has
worked
with
States
in
identifying
all
systems
that
are
part
of
each
combined
distribution
system.

Finally,
several
commenters
requested
that
the
wholesale
system
definition
replace
"
public
water
system"
with
"
water
system"
so
that
wholesale
systems
serving
fewer
than
25
people
would
not
be
considered
public
water
systems.
EPA
did
not
change
the
definition
in
today's
rule;
EPA
considers
any
water
system
to
be
a
public
water
system
(
PWS)
if
it
serves
25
or
more
people
either
directly
(
retail)
or
indirectly
(
by
providing
finished
water
to
a
consecutive
system)
or
through
a
combination
of
retail
and
consecutive
system
customers.
If
a
PWS
receives
water
from
an
unregulated
entity,
itthat
PWS
must
meet
all
compliance
requirements
(
including
monitoring
and
treatment
techniques)
that
any
other
public
water
system
that
uses
source
water
of
unknown
quality
must
meet.
73
C.
LRAA
MCLs
for
TTHM
and
HAA5
1.
Today's
rule
This
rule
requires
the
use
of
locational
running
annual
averages
(
LRAAs)
to
determine
compliance
with
the
Stage
2
MCLs
of
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5.
All
systems,

including
consecutive
systems,
must
comply
with
the
MCLs
for
TTHM
and
HAA5
using
sampling
sites
identified
under
the
Initial
Distribution
System
Evaluation
(
IDSE)
or
using
existing
Stage
1
DBPR
compliance
monitoring
locations
(
as
discussed
in
Section
IV.
F).
EPA
has
dropped
the
proposed
phased
approach
for
LRAA
implementation
(
Stage
2A
and
Stage
2B)
by
removing
Stage
2A
and
redesignating
Stage
2B
as
Stage
2.

Details
of
monitoring
requirements
and
compliance
schedules
are
discussed
in
preamble
Sections
IV.
G
and
IV.
E,
respectively,
and
may
be
found
in
subpart
V
of
today's
rule.

2.
Background
and
analysis
The
MCLs
for
TTHM
and
HAA5
are
the
same
as
those
proposed,
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5
as
an
LRAA.
See
the
proposed
rule
(
68
FR
49584,
August
18,
2003)

(
USEPA
2003a)
for
a
more
detailed
discussion
of
the
analysis
supporting
the
MCLs.
The
primary
objective
of
the
LRAA
is
to
reduce
exposure
to
high
DBP
levels.
For
an
LRAA,
an
annual
average
must
be
computed
at
each
monitoring
location.
The
RAA
compliance
basis
of
the
1979
TTHM
rule
and
the
Stage
1
DBPR
allows
a
system­
wide
annual
average
under
which
high
DBP
concentrations
in
one
or
more
locations
are
averaged
with,
and
dampened
by,
lower
concentrations
elsewhere
in
the
distribution
system.
Figure
IV.
C­
1
illustrates
the
difference
in
calculating
compliance
with
the
MCLs
for
TTHM
between
a
Stage
1
DBPR
RAA,
and
the
Stage
2
DBPR
LRAA.
74
75
First
Quarter
Average
of
All
Samples
Second
Quarter
Third
Quarter
Fourth
Q
uarter
Average
of
All
Samples
Average
of
All
Samples
Average
of
All
Samples
Running
Annual
Average
of
Quarterly
Averages
MUST
BE
BELOW
MCL
Stage
1
DBPR
First
Quarter
Second
Quarter
Third
Quarter
Fourth
Q
uarter
Stage
2
DBPR
First
Quarter
Second
Quarter
Third
Quarter
Fourth
Q
uarter
LRAA
1
MUST
BE
BELOW
MCL
First
Quarter
Second
Quarter
Third
Quarter
Fourth
Quarter
LRAA
3
MUST
BE
BELOW
MCL
First
Quarter
Second
Quarter
Third
Quarter
Fourth
Q
uarter
LRAA
2
MUST
BE
BELOW
MCL
First
Quarter
Second
Quarter
Third
Quarter
Fourth
Quarter
LRAA
4
MUST
BE
BELOW
MCL
Distribut
ion
System
Sampl
ing
Loc
ation
Figure
IV.
C­
1.
Comparison
of
RAA
and
LRAA
compliance
calculations1.

1Stage
2
DBPR
sampling
locations
will
be
selected
based
on
the
results
of
an
IDSE
and
may
occur
at
locations
different
from
Stage
1
DBPR
sampling
sites.
76
EPA
and
the
Stage
2
M­
DBP
Advisory
Committee
considered
an
array
of
alternative
MCL
strategies.
The
Advisory
Committee
discussions
primarily
focused
on
the
relative
magnitude
of
exposure
reduction
versus
the
expected
impact
on
the
water
industry
and
its
customers.

Strategies
considered
included
across
the
board
requirements,
such
as
significantly
decreasing
the
MCLs
(
e.
g.,
40/
30)
or
single
hit
MCLs
(
e.
g.,
all
samples
must
be
below
80/
60);
and
risk
targeting
requirements.
In
the
process
of
evaluating
alternatives,
EPA
and
the
Advisory
Committee
reviewed
vast
quantities
of
data
and
many
analyses
that
addressed
health
effects,
DBP
occurrence,

predicted
reductions
in
DBP
levels,
predicted
technology
changes,
and
capital,
annual,
and
household
costs.
The
Advisory
Committee
recommended
and
EPA
proposed
the
risk
targeting
approach
of
80/
60
as
an
LRAA
preceded
by
an
IDSE.
Today's
rule
finalizes
these
requirements.

EPA
has
chosen
compliance
based
on
an
LRAA
due
to
concerns
about
levels
of
DBPs
above
the
MCL
in
some
portions
of
the
distribution
system.
The
LRAA
standard
will
eliminate
system­
wide
averaging
of
monitoring
results
from
different
monitoring
locations.
The
individuals
served
in
areas
of
the
distribution
system
with
above
average
DBP
occurrence
levels
masked
by
averaging
under
an
RAA
are
not
receiving
the
same
level
of
health
protection.
Although
an
LRAA
standard
still
allows
averaging
at
a
single
location
over
an
annual
period,
EPA
concluded
that
changing
the
basis
of
compliance
from
an
RAA
to
an
LRAA
will
result
in
decreased
exposure
to
higher
DBP
levels
(
see
Section
VI
for
predictions
of
DBP
reductions
under
the
LRAA
MCLs).

This
conclusion
is
based
on
three
considerations:

1)
There
is
considerable
evidence
that
under
the
current
RAA
MCL
compliance
monitoring
requirements,
a
small
but
significant
proportion
of
monitoring
locations
experience
high
DBP
levels
at
least
some
of
the
time.
Of
systems
that
collected
data
under
the
Information
77
Collection
Rule
that
met
the
Stage
1
DBPR
RAA
MCLs,
14
percent
had
TTHM
single
sample
concentrations
greater
than
the
Stage
1
MCL,
and
21
percent
had
HAA5
single
sample
concentrations
above
the
MCL.
Although
most
TTHM
and
HAA5
samples
were
below
100
:
g/
L,
some
ranged
up
to
140
:
g/
L
and
130
:
g/
L,
respectively.

2)
In
some
situations,
the
populations
served
by
certain
portions
of
the
distribution
system
consistently
receive
water
that
exceeds
0.080
mg/
L
for
TTHM
or
0.060
mg/
L
for
HAA5
(
both
as
LRAAs)
even
though
the
system
is
in
compliance
with
Stage
1
MCLs).
Of
Information
Collection
Rule
systems
meeting
the
Stage
1
DBPR
MCLs
as
RAAs,
five
percent
had
monitoring
locations
that
exceeded
0.080
mg/
L
TTHM
and
three
percent
exceeded
0.060
mg/
L
HAA5
as
an
annual
average
(
i.
e.,
as
LRAAs)
by
up
to
25%.
Five
percent
of
plants
that
achieved
compliance
with
the
Stage
1
TTHM
MCL
of
0.080
mg/
L
based
on
an
RAA
had
a
particular
sampling
location
that
exceeded
0.080
mg/
L
as
an
LRAA
(
(
calculated
as
indicated
in
Figure
IV.
C­
1).
Customers
served
at
these
locations
consistently
received
water
with
TTHM
and/
or
HAA5
concentrations
higher
than
the
system­
wide
average
and
higher
than
the
MCL.

3)
Compliance
based
on
an
LRAA
will
remove
the
opportunity
for
systems
to
average
out
samples
from
high
and
low
quality
water
sources.
Some
systems
are
able
to
comply
with
an
RAA
MCL
even
if
they
have
a
plant
with
a
poor
quality
water
source
(
that
thus
produces
high
concentrations
of
DBPs)
because
they
have
another
plant
that
has
a
better
quality
water
source
(
and
thus
lower
concentrations
of
DBPs).
Individuals
served
by
the
plant
with
the
poor
quality
source
will
usually
have
higher
DBP
exposure
than
individuals
served
by
the
other
plant.

In
part,
both
the
TTHM
and
HAA5
classes
are
regulated
because
they
occur
at
high
levels
and
represent
chlorination
byproducts
that
are
produced
from
source
waters
with
a
wide
78
range
of
water
quality.
The
combination
of
TTHM
and
HAA5
represent
a
wide
variety
of
compounds
resulting
from
bromine
substitution
and
chlorine
substitution
reactions
(
e.
g.,

bromoform
has
three
bromines,
TCAA
has
three
chlorines,
BDCM
has
one
bromine
and
two
chlorines).
EPA
believes
that
the
TTHM
and
HAA5
classes
serve
as
an
indicator
for
unidentified
and
unregulated
DBPs.
EPA
believes
that
controlling
the
occurrence
levels
of
TTHM
and
HAA5
will
help
control
the
overall
levels
of
chlorination
DBPs.

3.
Summary
of
major
comments
Commenters
supported
the
proposed,
risk­
targeted
MCL
strategy
over
the
alternative
MCL
strategies
that
were
considered
by
the
Advisory
Committee
as
the
preferred
regulatory
strategy.
Commenters
concurred
with
EPA's
analysis
that
such
an
approach
will
reduce
peak
and
average
DBP
levels.
Commenters
supported
the
Stage
2
long­
term
MCLs
of
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5
as
LRAAs.

EPA
received
many
comments
on
today's
MCLs
specific
to
consecutive
systems.
While
commenters
supported
consecutive
system
compliance
with
the
Stage
2
DBPR
in
order
to
provide
comparable
levels
of
public
health
protection,
they
noted
that
it
would
be
difficult
for
many
consecutive
systems
to
meet
Stage
2
requirements
because
they
have
not
had
to
meet
the
full
scope
of
DBP
requirements
under
previous
rules.
EPA
has
developed
a
training
and
outreach
program
to
assist
these
systems
and
encourages
States,
wholesale
systems,
and
professional
associations
to
also
provide
assistance.

Some
commenters
expressed
concern
about
holding
consecutive
systems
responsible
for
water
quality
over
which
they
have
no
control.
Several
commenters
were
concerned
about
the
establishment
of
contracts
between
wholesale
and
consecutive
systems,
including
concern
about
a
79
strain
on
their
relationship,
wholesale
system
reluctance
to
commit
to
keep
DBPs
at
a
level
suggested
by
the
consecutive
systems,
and
the
time
and
money
it
could
take
to
work
out
differences.
Although
setting
up
a
contract
is
a
prudent
business
action,
commenters
noted
that
small
consecutive
water
systems
have
few
resources
to
sue
for
damages
should
the
wholesaler
provide
water
exceeding
the
MCL.

The
purpose
of
DBPRs
is
to
protect
public
health
from
exposure
to
high
DBP
levels.
Not
requiring
violations
when
distributed
water
exceeds
MCLs
undermines
the
intent
of
the
rule.

While
EPA
recognizes
consecutive
systems
do
not
have
full
control
over
the
water
they
receive,

agreements
between
wholesale
and
consecutive
systems
may
specify
water
quality
and
actions
required
of
the
wholesaler
if
those
water
quality
standards
are
not
met.

Finally,
commenters
recommended
that
the
Stage
2A
provisions
in
the
proposed
rule
be
removed.
These
provisions
(
compliance
with
locational
running
annual
average
MCLs
of
0.120
mg/
L
for
TTHM
and
0.100
mg/
L
for
HAA5)
required
systems
to
comply
with
the
Stage
1
MCLs
(
as
running
annual
averages)
and
the
Stage
2A
MCLs
(
as
LRAAs)
concurrently
until
systems
were
required
to
comply
with
Stage
2B
MCLs.
Commenters
noted
that
having
two
separate
MCLs
for
an
individual
system
to
comply
with
at
the
same
time
was
confusing
to
the
system
and
its
customers.
In
addition,
State
resources
needed
for
compliance
determinations
and
data
management
for
this
short­
term
requirement
would
be
resource­
intensive.
Finally,
resources
spent
to
comply
with
Stage
2A
would
be
better
spent
in
complying
with
Stage
2B,
especially
given
that
some
of
the
changes
for
Stage
2A
compliance
might
not
provide
any
benefit
for
Stage
2B.
Since
EPA
agrees
with
commenters'
concerns,
the
Stage
2A
requirements
have
been
removed
from
the
final
rule.
80
D.
BAT
for
TTHM
and
HAA5
1.
Today's
rule
Today,
EPA
is
identifying
the
best
available
technology
(
BAT)
for
the
TTHM
and
HAA5
LRAA
MCLs
(
0.080
mg/
L
and
0.060
mg/
L
respectively)
for
systems
that
treat
their
own
source
water
as
one
of
the
three
following
technologies:

(
1)
GAC
adsorbersGAC10
(
granular
activated
carbon
filter
beds
with
at
least
10
minutes
ofan
empty
­
bed
contact
time
and
an
annual
average
reactivation/
replacement
frequency
no
greater
than
120
days,
plus
enhanced
coagulation
or
enhanced
softening.

(
2)
GAC
adsorbers
with
at
least
20
minutes
of
empty
bedof
10
minutes
based
on
average
daily
flow
and
a
carbon
reactivation
frequency
of
every
120
days)

(
2)
GAC20
(
granular
activated
carbon
filter
beds
with
an
empty­
bed
contact
time
and
an
annual
average
reactivation/
replacement
frequency
no
greater
than
240
days.
of
20
minutes
based
on
average
daily
flow
and
a
carbon
reactivation
frequency
of
every
240
days)

(
3)
Nanofiltration
(
NF)
using
a
membrane
with
a
molecular
weight
cutoff
of
1000
Daltons
or
less.

EPA
is
specifying
a
different
BAT
for
consecutive
systems
than
for
systems
that
treat
their
own
source
water
to
meet
the
TTHM
and
HAA5
LRAA
MCLs.
The
consecutive
system
BAT
is
chloramination
with
management
of
hydraulic
flow
and
storage
to
minimize
residence
time
in
the
distribution
system
for
systems
that
serve
at
least
10,000
people
and
management
of
hydraulic
flow
and
storage
to
minimize
residence
time
in
the
distribution
system
for
systems
that
serve
81
fewer
than
10,000
people.

2.
Background
and
analysis
The
BATs
are
the
same
as
was
proposed,
except
that
consecutive
systems
serving
fewer
than
10,000
people
do
not
have
chloramination
as
part
of
the
consecutive
system
BAT.
See
the
proposal
(
68
FR
49588,
August
18,
2003)
(
USEPA
2003a)
for
more
detail
on
the
analysis
supporting
these
requirements.
The
Safe
Drinking
Water
Act
directs
EPA
to
specify
BAT
for
use
in
achieving
compliance
with
the
MCL.
Systems
unable
to
meet
the
MCL
after
application
of
BAT
can
get
a
variance
(
see
Section
IV.
K
for
a
discussion
of
variances).
Systems
are
not
required
to
use
BAT
in
order
to
comply
with
the
MCL.
PWSs
may
use
any
State­
approved
technologies
as
long
as
they
meet
all
drinking
water
standards.

EPA
examined
BAT
options
first
by
analyzing
data
from
the
Information
Collection
Rule
treatment
studies
designed
to
evaluate
the
ability
of
GAC
and
NF
to
remove
DBP
precursors.

Based
on
the
treatment
study
results,
GAC
is
effective
for
controlling
DBP
formation
for
waters
with
influent
TOC
concentrations
below
approximately
6
mg/
L
(
based
on
the
Information
Collection
Rule
and
NRWA
data,
over
90
percent
of
plants
have
average
influent
TOC
levels
below
6
mg/
L
(
USEPA
2003c)).
Of
the
plants
that
conducted
an
Information
Collection
Rule
GAC
treatment
study,
approximately
70
percent
of
the
surface
water
plants
studies
could
meet
the
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5
MCLs,
with
a
20
percent
safety
factor
(
i.
e.,
0.064
mg/
L
and
0.048
mg/
L,
respectively)
using
GAC
with
10
minutes
of
empty
bed
contact
time
and
a
120
day
reactivation
frequency,
and
78percent
of
the
plants
could
meet
the
MCLs
with
a
20
percent
safety
factor
using
GAC
with
20
minutes
of
empty
bed
contact
time
and
a
240
day
reactivation
frequency.
Because
the
treatment
studies
were
conducted
at
plants
with
much
poorer
82
water
quality
than
the
national
average,
EPA
believes
that
much
higher
percentages
of
plants
nationwide
could
meet
the
MCLs
with
the
proposed
GAC
BATs.

Among
plants
using
GAC,
larger
systems
would
likely
realize
an
economic
benefit
from
on­
site
reactivation,
which
could
allow
them
to
use
smaller,
10­
minute
empty
bed
contact
time
contactors
with
more
frequent
reactivation
(
i.
e.,
120
days
or
less).
Most
small
systems
would
not
find
it
economically
advantageous
to
install
on­
site
carbon
reactivation
facilities,
and
thus
would
opt
for
larger,
20­
minute
empty
bed
contact
time
contactors,
with
less
frequent
carbon
replacement
(
i.
e.,
240
days
or
less).

The
Information
Collection
Rule
treatment
study
results
also
demonstrated
that
nanofiltration
was
the
better
DBP
control
technology
for
ground
water
sources
with
high
TOC
concentrations
(
i.
e.,
above
approximately
6
mg/
L).
The
results
of
the
membrane
treatment
studies
showed
that
all
ground
water
plants
could
meet
the
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5
MCLs,
with
a
20%
safety
factor
(
i.
e.,
0.064
mg/
L
and
0.048
mg/
L,
respectively)
at
the
system
average
distribution
system
residence
time
using
nanofiltration.
Nanofiltration
would
be
less
expensive
than
GAC
for
high
TOC
ground
waters,
which
generally
require
minimal
pretreatment
prior
to
the
membrane
process.
Also,
nanofiltration
is
an
accepted
technology
for
treatment
of
high
TOC
ground
waters
in
Florida
and
parts
of
the
Southwest,
areas
of
the
country
with
elevated
TOC
levels
in
ground
waters.

The
second
method
that
EPA
used
to
examine
alternatives
for
BAT
was
the
Surface
Water
Analytical
Tool
model
that
was
developed
to
compare
alternative
regulatory
strategies
as
part
of
the
Stage
1
and
Stage
2
M­
DBP
Advisory
Committee
deliberations.
EPA
modeled
a
number
of
BAT
options.
In
the
model,
GAC10
was
defined
as
granular
activated
carbon
with
an
83
empty
bed
contact
time
of
10
minutes
and
a
reactivation
or
replacement
interval
of
90
days
or
longer.
GAC20
was
defined
as
granular
activated
carbon
with
an
empty
bed
contact
time
of
20
minutes
and
a
reactivation
or
replacement
interval
of
90
days
or
longer.

The
compliance
percentages
forecasted
by
the
SWAT
model
are
indicated
in
Table
IV.
D­

1.
EPA
estimates
that
more
than
97
percent
of
large
systems
will
be
able
to
achieve
the
Stage
2
MCLs
with
the
GAC
BAT,
regardless
of
post­
disinfection
choice
(
Seidel
Memo,
2001).
Because
the
source
water
quality
(
e.
g.,
DBP
precursor
levels)
in
medium
and
small
systems
is
expected
to
be
comparable
to
or
better
than
that
for
the
large
system
(
USEPA
2005f),
EPA
believes
it
is
conservative
to
assume
that
at
least
90
percent
of
medium
and
small
systems
will
be
able
to
achieve
the
Stage
2
MCLs
if
they
were
to
apply
one
of
the
proposed
GAC
BATs.
EPA
assumes
that
small
systems
may
adopt
GAC20
in
a
replacement
mode
(
with
replacement
every
240
days)

over
GAC10
because
it
may
not
be
economically
feasible
for
some
small
systems
to
install
and
operate
an
on­
site
GAC
reactivation
facility.
Moreover,
some
small
systems
may
find
nanofiltration
cheaper
than
the
GAC20
in
a
replacement
mode
if
their
specific
geographic
locations
cause
a
relatively
high
cost
for
routine
GAC
shipment.

Table
IV.
D­
1.
SWAT
Model
Predictions
of
Percent
of
Large
Plants
in
Compliance
With
TTHM
and
HAA5
Stage
2
MCLs
After
Application
of
Specified
Treatment
Technologies
Technology
Compliance
with
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5
LRAAs
Compliance
with
0.064
mg/
L
TTHM
and
0.048
mg/
L
HAA5
LRAAs
(
MCLs
with
20%
Safety
Factor)

Residual
Disinfectant
All
Systems
Residual
Disinfectant
All
Systems
Chlorine
Chloramine
Chlorine
Chloramine
Enhanced
Coagulation
(
EC)
73.5%
76.9%
74.8%
57.2%
65.4%
60.4%
Technology
Compliance
with
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5
LRAAs
Compliance
with
0.064
mg/
L
TTHM
and
0.048
mg/
L
HAA5
LRAAs
(
MCLs
with
20%
Safety
Factor)

84
EC
(
no
predisinfection
73.4%
88.0%
78.4%
44.1%
62.7%
50.5%

EC
&
GAC10
100%
97.1%
99.1%
100%
95.7%
98.6%

EC
&
GAC20
100%
100%
100%
100%
100%
100%

EC
&
All
Chloramines
NA
83.9%
NA
NA
73.6%
NA
Source:
McGuire
(
2001).
NOTENote:
Enhanced
coagulation/
softening
is
required
under
the
Stage
1
DBPR
for
conventional
plants.
Source:
Seidel
(
2001).

The
BAT
requirements
for
large
consecutive
systems
are
the
same
as
proposed,
but
the
requirements
have
changed
for
small
consecutive
systems.
EPA
believes
that
the
best
compliance
strategy
for
consecutive
systems
is
to
collaborate
with
wholesalers
on
the
water
quality
they
need.

For
consecutive
systems
that
are
having
difficulty
meeting
the
MCLs,
EPA
is
specifying
a
BAT
of
chloramination
with
management
of
hydraulic
flow
and
storage
to
minimize
residence
time
in
the
distribution
system
for
systems
serving
at
least
10,000
and
management
of
hydraulic
flow
and
storage
to
minimize
residence
time
in
the
distribution
system
for
systems
serving
fewer
than
10,000.
EPA
believes
that
small
consecutive
systems
can
use
this
BAT
to
comply
with
the
Stage
2
DBPR,
but
if
they
cannot,
then
they
can
apply
to
the
State
for
a
variance.

Chloramination
has
been
used
for
residual
disinfection
for
many
years
to
minimize
the
formation
of
chlorination
DBPs,
including
TTHM
and
HAA5
(
USEPA
2003d).
EPA
estimates
that
over
50
percent
of
large
subpart
H
systems
serving
at
least
10,000
use
chloramination
for
Stage
1.
The
BAT
provision
to
manage
hydraulic
flow
and
minimize
residence
time
in
the
distribution
system
is
to
facilitate
the
maintenance
of
the
chloramine
residual
and
minimize
the
85
likelihood
for
nitrification.
EPA
has
not
included
chloramination
for
consecutive
systems
as
part
of
the
BAT
for
systems
serving
fewer
than
10,000
due
to
concerns
about
their
ability
to
properly
control
the
process,
given
that
many
have
no
treatment
capability
or
expertise
and
the
Agency's
concern
about
such
systems
having
operational
difficulties
such
as
distribution
system
nitrification.

EPA
believes
that
the
BATs
for
nonconsecutive
systems
are
not
appropriate
for
consecutive
systems
because
their
efficacy
in
controlling
DBPs
is
based
on
precursor
removal.

Consecutive
systems
face
the
unique
challenge
of
receiving
waters
in
which
DBPs
are
already
present
if
the
wholesale
system
has
used
a
residual
disinfectant,
which
the
BATs
for
nonconsecutive
systems
do
not
effectively
remove.
GAC
is
not
cost­
effective
for
removing
DBPs.

Nanofiltration
is
only
moderately
effective
at
removing
THMs
or
HAAs
if
membranes
with
a
very
low
molecular
weight
cutoff
(
and
very
high
cost
of
operation
are
employed).
Therefore,
GAC
and
nanofiltration
are
not
appropriate
BATs
for
consecutive
systems.

3.
Summary
of
major
comments
Commenters
concurred
with
EPA's
identification
of
BATs
for
non­
consecutive
systems
but
expressed
concern
about
the
BAT
for
consecutive
systems.
Many
commenters
agreed
that
Stage
2
compliance
for
consecutive
systems
would
usually
best
be
achieved
by
improved
treatment
by
the
wholesale
system.
However,
they
noted
that
the
proposed
BAT
may
not
be
practical
for
compliance
if
water
delivered
to
the
consecutive
system
is
at
or
near
DBP
MCLs.
In
addition,
chloramination
requires
operator
supervision
and
adjustment
and
many
consecutive
systems
that
buy
water
may
be
reluctant
to
operate
chemical
feed
systems.
Therefore,
EPA
included
chloramines
as
part
of
the
BAT
in
today's
rule
only
for
systems
serving
at
least
10,000
because
of
the
operator
attention
it
requires
and
concerns
with
safety
and
nitrification.
While
86
some
commenters
believed
that
having
a
BAT
for
consecutive
systems
contradicts
the
premise
of
the
Stage
1
DBPR
that
DBPs
are
best
controlled
through
TOC
removal
and
optimizing
disinfection
processes,
the
SDWA
requires
EPA
to
identify
a
BAT
for
all
systems
required
to
meet
an
MCL.
No
commenter
recommended
an
alternative
BAT.
EPA
still
believes
that
precursor
removal
remains
a
highly
effective
strategy
to
reduce
DBPs.
Thus,
EPA
encourages
States
to
work
with
wholesale
systems
and
consecutive
systems
to
identify
strategies
to
ensure
compliance,
especially
those
systems
with
DBP
levels
close
to
the
MCL.

E.
Compliance
Schedules
1.
Today's
rule
This
section
specifies
compliance
dates
for
the
IDSE
and
MCL
compliance
requirements
in
today's
rule.
As
described
elsewhere
in
Section
IV
of
this
preamble,
today's
rule
requires
PWSs
to
carry
out
the
following
activities:

C
Conduct
initial
distribution
system
evaluations
(
IDSEs)
on
a
required
schedule.
Systems
may
comply
by
using
any
of
four
approaches
for
which
they
qualify
(
standard
monitoring,

system
specific
study,
40/
30
certification,
or
very
small
system
waiver).

C
Determine
Stage
2
monitoring
locations
based
on
the
IDSE.

C
Comply
with
Stage
2
MCLs
on
a
required
schedule.

Compliance
dates
for
these
activities
vary
by
PWS
size.
Table
IV.
E­
1
and
Figure
IV.
E­
1
specify
IDSE
and
Stage
2
compliance
dates.
Consecutive
systems
of
any
size
must
comply
with
the
requirements
of
the
Stage
2
DBPR
on
the
same
schedule
as
required
for
the
largest
system
in
the
combined
distribution
system.
87
Table
IV.
E­
1.
IDSE
and
Stage
2
Compliance
Dates.

Requirement
Compliance
Dates
by
PWS
Size
(
retail
population
served)
1
CWSs
and
NTNCWSs
serving
at
least
100,000
CWSs
and
NTNCWSs
serving
50,000­
99,999
CWSs
and
NTNCWSs
serving
10,000­
49,999
CWSs
and
NTNCWSs
serving
fewer
than
<
10,000
NTNCWSs
serving
<
10,000
88
Submit
IDSE
monitoring
plan
OR
Submit
IDSE
Ssystem
specific
study
plan
OR
Submit
40/
30
certification
OR
Receive
very
small
system
waiver
from
State
No
later
than
[
INSERT
DATE
SIX
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
12
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
18
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
24
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
2
October
1,
2006
April
1,
2007
October
1,
2007
April
1,
2008
Not
applicable
89
Complete
individual
distribution
system
evaluationNo
later
than
[
INSERT
DATE
30
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
36
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
42
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
48
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
2standard
monitoring
or
system
specific
study
September
30,
2008
March
31,
2009
September
30,
2009
March
31,
2010
Not
applicable
90
Submit
IDSE
Report
No
later
than
[
INSERT
DATE
33
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
January
1,
2009
July
1,
2009
No
later
than
[
INSERT
DATE
39
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
45
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
51
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
2Januar
y
1,
2010
July
1,
2010
Not
applicable
91
Begin
subpart
V
(
Stage
2)

compliance
monitoring2monitoring
2
No
later
than
[
INSERT
DATE
72
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
78
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
90
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]
No
later
than
[
INSERT
DATE
90
MONTHS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER]

April
1,
2012
October
1,
2012
October
1,
2013
October
1,
2013
(
October
1,
2014
if
Cryptosporidium
monitoring
is
required
under
Subpart
W)

1
Wholesale
and
consecutive
systems
that
are
part
of
a
combined
distribution
system
must
comply
based
on
the
schedule
required
of
the
largest
system
in
the
combined
distribution
system.

2
States
may
grant
up
to
an
additional
2
years
for
systems
making
capital
improvements.
92
Systems
serving
at
least
100,000
people1
IDSE
Plan
Due
IDSE
Report
Due
Compliance
Systems
serving
50,000
to
99,999
people1
IDSE
Plan
Due
IDSE
Report
Due
Compliance
Systems
serving
10,000
to
49,999
people1
IDSE
Plan
Due
IDSE
Report
Due
Compliance
Systems
serving
fewer
than
10,000
people1
IDSE
Plan
Due
IDSE
Report
Due
Compliance
Year
1
Year
2
Year
3
Year
4
Year
10
Year
11
Year
5
Year
6
Year
7
Year
8
Years
following
effective
date
Crypto
monitoring
Crypto
monitoring
Treatment
Installation
Possible
Extension
2
IDSE
mon.

IDSE
mon.
Treatment
Installation
Possible
Extension
2
Year
9
Treatment
Installation
3
Possible
Extension
2
IDSE
mon.

E.
Coli
mon.
Crypto
mon.
3
Year
1
Year
2
Year
3
Year
4
Year
9
Year
10
Year
11
Year
5
Year
6
Year
7
Year
8
Crypto
monitoring
IDSE
mon.
Treatment
Installation
Possible
Extension
2
Figure
IV.
E­
1.
Final
Stage
2
DBPR
and
LT2ESWTR
Implementation
Schedule.

1
Includes
all
systems
that
are
part
of
a
combined
distribution
system
that
has
a
largest
system
with
this
population.

2
A
State
may
grant
up
to
a
two
year
extension
for
systems
to
comply
if
the
State
determines
that
additional
time
is
necessary
for
capital
improvements
needed
for
compliance.

3
Subpart
H
systems
serving
fewer
than
10,000
that
must
conduct
Crypto
monitoring
have
an
additional
12
months
to
comply
with
Stage
2
DBPR
MCLs.
93
2.
Background
and
analysis
The
compliance
schedule
in
today's
final
rule
stems
from
the
risk­
targeted
approach
of
the
rule,
wherein
PWSs
conduct
initial
monitoring
to
determine
locations
and
concentrations
of
high
DBPs.
A
primary
objective
of
this
schedule
is
to
ensure
that
PWSs
identify
locations
with
high
DBP
concentrations
and
provide
appropriate
additional
treatment
in
a
timely
manner
for
high
risk
areas,
while
not
requiring
low
risk
systems
to
add
additional
treatment.
The
compliance
schedule
balances
the
objective
of
early
risk­
targeted
monitoring
with
adequate
time
for
PWSs
and
the
State
or
primacy
agency
to
assure
full
implementation
and
compliance.
EPA
is
establishing
concurrent
compliance
schedules
under
the
Stage
2
DBPR
for
all
systems
(
both
wholesale
systems
and
consecutive
systems)
in
a
particular
combined
distribution
system
because
this
will
assure
comparable
risk­
based
targeting
information
being
available
at
the
same
time
for
all
PWSs
that
are
part
of
a
combined
distribution
system
and
thereby
allow
for
more
cost­
effective
compliance
with
TTHM
and
HAA5
MCLs.

SDWA
section
1412(
b)(
10)
states
that
a
drinking
water
regulation
shall
take
effect
3
years
from
the
promulgation
date
unless
the
Administrator
determines
that
an
earlier
date
is
practicable.

Today's
rule
requires
PWSs
to
begin
monitoring
prior
to
3
years
from
the
promulgation
date.

Based
on
EPA's
assessment
and
recommendations
of
the
Advisory
Committee,
as
described
in
this
section,
EPA
has
determined
that
these
monitoring
start
dates
are
practicable
and
appropriate.

Systems
must
submit
their
IDSE
plans
(
monitoring
plans
for
standard
monitoring,
study
plans
for
system
specific
studies)
to
the
primacy
agency
for
review
and
approval.
The
State
or
primacy
agency
will
then
have
12
months
to
review,
and,
as
necessary,
consult
with
the
system.
A
number
of
PWSs
will
then
conduct
one
year
of
distribution
system
monitoring
for
TTHM
and
HAA5
at
locations
other
than
those
currently
used
for
Stage
1
DBPR
compliance
monitoring.
At
the
conclusion
of
this
monitoring,
these
PWSs
have
three
months
to
evaluate
analysis
and
94
monitoring
results
and
submit
Stage
2
compliance
monitoring
locations
and
schedules
to
the
State
or
primacy
agency.
Where
required,
PWSs
must
provide
the
necessary
level
of
treatment
to
comply
with
the
Stage
2
MCLs
within
three
years
of
the
completion
of
State
or
primacy
agency
review
of
the
IDSE
report,
though
States
may
allow
an
additional
two
years
for
PWSs
making
capital
improvements.

EPA
has
modified
the
proposed
compliance
schedule
to
stagger
monitoring
start
dates
for
PWSs
serving
10,000
to
99,999
people
and
to
allow
more
time
for
development
and
review
of
IDSE
monitoring
plans
prior
to
the
start
of
monitoring.
The
following
discussion
addresses
these
changes
from
the
proposal.

The
proposed
rule
required
all
PWSs
serving
at
least
10,000
people
(
plus
smaller
systems
that
are
part
of
a
combined
distribution
system
with
a
PWS
that
serves
at
least
10,000
people)
to
complete
IDSE
monitoring
and
submit
IDSE
reports
(
including
recommended
Stage
2
compliance
monitoring
locations)
two
years
after
rule
promulgation,
followed
by
one
year
for
review
of
IDSE
reports,
after
which
systems
had
three
years
to
come
into
compliance
with
Stage
2B
MCLs.

Under
today's
final
rule,
PWSs
serving
at
least
100,000
people
(
plus
smaller
systems
that
are
part
of
the
combined
distribution
system)
will
meet
the
same
Stage
2
compliance
scheduledeadlines
as
proposed.
THowever,
the
timing
of
the
IDSE
has
been
changed
to
allow
for
a
more
even
workload
and
a
greater
opportunity
for
primacy
agency
involvement
(
e.
g.,
through
monitoring
plan
review
and
approval).
The
IDSE
plan
submission
dates
for
PWSs
serving
50,000
to
99,999
people
(
plus
smaller
systems
that
are
part
of
the
combined
distribution
system)
will
be
12
months
after
promulgationthe
effective
date;
for
PWSs
serving
10,000
to
49,999
(
plus
smaller
systems
that
are
part
of
the
combined
distribution
system),
the
IDSE
plan
submission
dates
will
be
18
months
after
promulgationthe
effective
date.
The
Stage
2
compliance
schedule
for
systems
serving
fewer
than
10,000
people
remains
the
same
as
proposed.
Stage
2
MCL
compliance
dates
95
are
modified
accordingly.

This
staggering
of
IDSE
start
dates
for
PWSs
serving
10,000
to
99,999
people
is
advantageous
in
several
respects:

C
Provides
PWSs
greater
assurance
that
IDSEs
are
properly
conducted
by
requiring
IDSE
plan
review
prior
to
conducting
the
IDSE.

C
Provides
additional
time
to
develop
budgets
and
establish
contracts
with
laboratories.

C
Spreads
out
the
workload
for
technical
assistance
and
guidance.
The
staggered
schedule
will
allow
States
and
EPA
to
provide
more
support
to
individual
PWSs
as
needed.

C
Provides
time
for
DBP
analytical
laboratories
to
build
capacity
as
needed
to
accommodate
the
sample
analysis
needs
of
PWSs
and
extends
and
smooths
the
demand
for
laboratory
services
C
Maintains
simultaneous
rule
compliance
with
the
LT2ESWTR
as
recommended
by
the
Stage
2
M­
DBP
Advisory
Committee
and
as
mandated
by
the
1996
SDWA
Amendments,

which
require
that
EPA
"
minimize
the
overall
risk
of
adverse
health
effects
by
balancing
the
risk
from
the
contaminant
and
the
risk
from
other
contaminants
the
concentrations
of
which
may
be
affected
by
the
use
of
a
treatment
technique
or
process
that
would
be
employed
to
attain
the
maximum
contaminant
level"
(
Sec.
1412(
b)(
5)(
B)(
i)).

The
Advisory
Committee
recommended
the
Initial
Distribution
System
Evaluation,
as
discussed
in
Section
IV.
F,
and
EPA
is
finalizing
an
IDSE
schedule
generally
consistent
with
the
Advisory
Committee
timeframe
recommendation,
but
modified
to
stagger
the
schedule
for
systems
serving
more
than
10,000
but
less
than
100,000,
and
to
address
public
comments
on
the
IDSE
requirements.

For
all
systems,
the
IDSE
schedule
has
been
revised
to
allow
systems
to
submit
and
States
or
primacy
agencies
to
review
(
and
revise,
if
necessary)
systems'
recommendations
for
IDSE
and
96
Stage
2
monitoring
locations,
while
still
allowing
systems
three
years
after
completion
of
the
State
or
primacy
agency
review
of
Stage
2
compliance
monitoring
locations
to
make
necessary
treatment
and
operational
changes
to
comply
with
Stage
2
MCLs.

Figure
IV.
E­
2
illustrates
compliance
schedules
for
examples
of
three
combined
distribution
systems,
with
the
schedule
dictated
by
the
retail
population
served
by
the
largest
system.

Figure
IV.
E­
2.
Schedule
Examples.

­
Wholesale
system
(
pop.
64,000)
with
three
consecutive
systems
(
pops.
21,000;
15,000;
5,000):
­
IDSE
monitoring
plan
due
for
all
systems
12
months
after
promulgationApril
1,
2007
since
wholesale
system
serves
50,000­
99,999
­
Stage
2
compliance
beginning
6.5
years
after
promulgationOctober
1,
2012
for
all
systems
­
Wholesale
system
(
pop.
4,000)
with
three
consecutive
systems
(
pops.
21,000;
5,000;
5,000):
­
IDSE
monitoring
plan
due
for
all
systems
18
months
after
promulgationOctober
1,
2007
since
the
largest
system
in
combined
distribution
system
serves
10,000­
49,999
­
Stage
2
compliance
beginning
7.5
years
after
promulgationOctober
1,
2013
for
all
systems
­
Wholesale
system
(
pop.
4,000)
with
three
consecutive
systems
(
pops.
8,000;
5,000;
5,000):
­
IDSE
monitoring
plan
due
for
all
systems
two
years
after
promulgationApril
1,
2008
since
no
individual
system
in
combined
distribution
system
exceeds
10,000
(
even
though
total
population
exceeds
10,000)
­
Stage
2
compliance
beginning
7.5
years
after
promulgationOctober
1,
2013
if
no
Cryptosporidium
monitoring
under
the
LT2ESWTR
is
required
or
beginning
8.5
years
after
promulgationOctober
1,
2014
if
Cryptosporidium
monitoring
under
the
LT2ESWTR
is
required
This
schedule
requires
wholesale
systems
and
consecutive
systems
that
are
part
of
a
combined
distribution
system
with
at
least
one
system
with
an
earlier
compliance
categorydeadline
to
conduct
their
IDSE
simultaneously
so
that
the
wholesale
system
will
be
aware
of
compliance
challenges
facing
the
consecutive
systems
and
will
be
able
to
implement
treatment
plant,
capital,

and
operational
improvements
as
necessary
to
ensure
compliance
of
both
the
wholesale
and
consecutive
systems.
The
Advisory
Committee
and
EPA
both
recognized
that
DBPs,
once
formed,
are
difficult
to
remove
and
are
generally
best
addressed
by
treatment
plant
improvements,
97
typically
through
precursor
removal
or
use
of
alternative
disinfectants.
For
a
wholesale
system
to
make
the
best
decisions
concerning
the
treatment
steps
necessary
to
meet
TTHM
and
HAA5
LRAAs
under
the
Stage
2
DBPR,
both
in
its
own
distribution
system
and
in
the
distribution
systems
of
consecutive
systems
it
serves,
the
wholesale
system
must
know
the
DBP
levels
throughout
the
combined
distribution
system.
Without
this
information,
the
wholesale
system
may
design
treatment
changes
that
allow
the
wholesale
system
to
achieve
compliance,
but
leave
the
consecutive
system
out
of
compliance.

In
summary,
the
compliance
schedule
for
today's
rule
maintains
the
earliest
compliance
dates
recommended
by
the
Advisory
Committee
for
PWSs
serving
at
least
100,000
people
(
plus
smaller
systems
that
are
part
of
the
combined
distribution
system).
These
PWSs
serve
the
majority
of
people.
The
schedule
also
maintains
the
latest
compliance
dates
the
Advisory
Committee
recommended,
which
apply
to
PWSs
serving
fewer
than
10,000
people.
EPA
has
staggered
compliance
schedules
for
PWSs
between
these
two
size
categories
in
order
to
facilitate
implementation
of
the
rule.
This
staggered
schedule
is
consistent
with
the
schedule
required
under
the
LT2ESWTR
promulgated
elsewhere
in
today's
Federal
Register.

3.
Summary
of
major
comments
EPA
received
significant
public
comment
on
the
compliance
schedule
in
the
August
18,

2003
proposal.
Major
issues
raised
by
commenters
include
providing
more
time
for
PWSs
to
prepare
for
monitoring,
giving
States
or
primacy
agencies
more
time
to
oversee
monitoring,
and
establishing
consistent
schedules
for
consecutive
PWSs.
A
summary
of
these
comments
and
EPA's
responses
follows.

Standard
monitoring
plan
and
system
specific
study
plan
preparation.
Many
commenters
were
concerned
about
the
proposed
requirement
to
develop
and
execute
an
IDSE
monitoring
plan
without
any
primacy
agency
review.
PWSs
specifically
expressed
concern
about
the
financial
98
commitment
without
prior
State
approval
and
noted
that
some
PWSs
would
need
more
than
the
time
allowed
under
the
proposed
rule
to
develop
and
implement
an
IDSE
monitoring
plan,

especially
without
an
opportunity
for
State
or
primacy
agency
review
and
approval.
Smaller
PWSs
may
require
substantial
time
and
planning
to
budget
for
IDSE
expenses,
especially
for
systems
that
have
not
previously
complied
with
DBP
MCLs.

EPA
recognizes
these
concerns
and
today's
final
rule
provides
time
for
PWSs
to
submit
IDSE
plans
(
monitoring
plans,
study
plans,
or
40/
30
certifications)
for
State
or
primacy
agency
review
and
more
time
before
having
to
begin
monitoring.
Specifically,
PWSs
serving
50,000
to
99,999
people
and
those
serving
10,000
to
49,999
people
must
submit
IDSE
plans
about
12
months
and
18
months
after
rule
promulgationthe
effective
date,
respectively,
and
complete
standard
monitoring
or
a
system
specific
study
36
months
or
45
monthswithin
two
years
after
rule
promulgation,
respectivelysubmitting
their
IDSE
plan.
This
is
significantly
more
time
than
was
specified
under
the
proposal,
where
these
systems
would
have
had
to
conduct
their
IDSE
and
submit
their
IDSE
report
24
months
after
promulgationthe
effective
date.
PWSs
serving
at
least
100,000
people
must
submit
IDSE
plans
about
six
months
after
rule
promulgationthe
effective
date
and
complete
standard
monitoring
or
a
system
specific
study
about
30
months
after
rule
promulgationthe
effective
date,
which
also
provides
more
time
than
was
specified
under
the
proposal.
PWSs
serving
fewer
than
10,000
people,
not
associated
with
a
larger
system
in
their
combined
distribution
system,
do
not
begin
monitoring
until
more
than
36
months
after
rule
promulgationthe
effective
date.

EPA
believes
that
the
final
compliance
schedule
allows
PWSs
sufficient
time
to
develop
IDSE
plans
with
these
compliance
dates.
The
schedule
also
allows
12
months
for
State
or
primacy
agency
review
of
IDSE
plans,
which
allows
additional
time
for
review
and
for
coordination
with
systems
and
provides
more
time
to
address
deficiencies
in
IDSE
plans.
This
is
99
especially
important
for
smaller
PWSs,
which
are
likely
to
need
the
most
assistance
from
States.

By
staggering
monitoring
start
dates,
today's
rule
also
eases
implementation
by
reducing
the
number
of
PWSs
that
will
submit
plans
at
any
one
time,
when
the
most
assistance
from
regulatory
agencies
will
be
required.

In
summary,
today's
schedule
has
been
modified
so
that
systems
are
required
to
submit
IDSE
plans
for
primacy
agency
review
and
approval
prior
to
conducting
their
IDSE.
Systems
can
consider
that
their
plan
has
been
approved
if
they
have
not
heard
back
from
the
State
by
the
end
of
the
State
review
period.
Systems
are
also
required
to
conduct
the
approved
monitoring
and
submit
their
IDSE
report
(
including
the
system's
recommended
Stage
2
compliance
monitoring)

for
State
or
primacy
agency
review
on
a
schedule
that
allows
for
systems
to
still
have
a
minimum
of
full
three
years
to
comply
with
Stage
2
following
State
or
primacy
agency
review
of
the
system's
Stage
2
recommended
monitoring.
As
with
the
review
of
plans,
systems
can
consider
that
their
IDSE
report
has
been
approved
if
they
have
not
heard
back
from
the
State
by
the
end
of
the
State
review
period.

State/
primacy
agency
oversight.
EPA
is
preparing
to
support
implementation
of
IDSE
requirements
that
must
be
completed
prior
to
States
achieving
primacy.
Several
States
have
expressed
concern
about
EPA
providing
guidance
and
reviewing
reports
from
systems
that
the
State
has
permitted,
inspected,
and
worked
with
for
a
long
time.
These
States
believe
that
their
familiarity
with
the
systems
enables
them
to
make
the
best
decisions
to
implement
the
rule
and
protect
public
health
and
that
the
rule
requirement
should
be
delayed
until
States
receive
primacy.

Commenters
were
concerned
that
some
States
will
not
participate
in
early
implementation
activities
and
indicated
that
States
would
prefer
monitoring
to
begin
24
months
after
rule
promulgation.
Commenters
also
noted
that
States
need
sufficient
time
to
become
familiar
with
the
rule,
train
their
staff,
prepare
primacy
packages,
and
train
PWSs.
100
EPA
agrees
that
State
familiarity
is
an
important
component
of
the
review
and
approval
process,
looks
forward
to
working
closely
with
the
State
drinking
water
program
representatives
during
IDSE
implementation,
and
welcomes
proactive
State
involvement.
However,
the
Agency
believes
that
delaying
implementation
of
risk­
based
IDSE
targeting
activities
until
States
receive
primacy
is
an
unacceptable
delay
in
public
health
protection
and
also
inconsistent
with
the
Advisory
Committee's
recommendations.
EPA
remains
committed
to
working
with
States
to
the
greatest
extent
feasible
to
implement
today's
rule,
consistent
with
the
schedule
promulgated
today.
For
States
unable
to
actively
participate
in
IDSE
implementation,
however,
EPA
believes
it
has
an
obligation
to
provide
support
and
guidance
to
PWSs
who
are
covered
and
independently
responsible
for
complying
with
the
IDSE
requirements
of
today's
rule
and
is
prepared
to
oversee
implementation.
Moreover,
EPA
believes
that
the
staggered
compliance
schedule
in
today's
final
rule
will
enhance
States'
ability
to
help
implement
the
rule.

Consecutive
systems.
Most
commenters
supported
consecutive
systems
being
on
the
same
IDSE
schedule
as
wholesale
systems,
recognizing
the
benefits
of
treatment
plant
capital
and
operational
improvements
by
the
wholesale
system
as
the
preferred
method
of
DBP
compliance,

with
the
timely
collection
of
DBP
data
throughout
the
combined
distribution
system
a
key
component.
Several
commenters
preferred
that
consecutive
systems
have
a
later
Stage
2
compliance
date
to
allow
for
evaluation
of
whether
wholesale
system
treatment
changes
are
adequate
to
ensure
compliance
and
to
consider
changes
to
water
delivery
specifications.

EPA
disagrees
with
those
commenters
recommending
a
different
Stage
2
compliance
date
and
thus
has
maintained
the
approach
in
the
proposal,
which
keeps
all
systems
that
are
part
of
a
combined
distribution
system
(
the
interconnected
distribution
system
consisting
of
the
distribution
systems
of
wholesale
systems
and
of
the
consecutive
systems
that
receive
finished
water)
on
the
same
Stage
2
compliance
schedule.
Extending
the
Stage
2
compliance
dates
would
unnecessarily
101
delay
the
public
health
protection
afforded
by
this
rule.
Consecutive
systems
must
be
able
to
evaluate
whether
wholesale
system
changes
are
sufficient
to
ensure
compliance
and,
if
they
are
not,
to
make
cost­
effective
changes
to
ensure
compliance
where
wholesale
system
efforts
address
some,
but
not
all,
of
the
concerns
with
compliance.
Public
health
protection
through
compliance
with
Stage
2
MCLs
will
occur
on
the
schedule
of
the
largest
system
for
all
systems
in
the
combined
distribution
system
(
regardless
of
size).
If
a
consecutive
system
must
make
capital
improvements
to
comply
with
this
rule,
the
State
may
use
its
existing
authority
to
grant
up
to
an
additional
24
months
to
that
system.
In
addition,
implementation
and
data
tracking
will
be
simplified
because
all
systems
in
a
combined
distribution
system
will
be
on
the
same
IDSE
and
Stage
2
compliance
schedule.
EPA
believes
that
this
is
a
better
approach
from
both
a
public
health
standpoint
and
an
implementation
standpoint.

EPA
agrees
with
many
commenters
that
a
high
level
of
coordination
among
wholesaler,

consecutive
system,
and
States
will
be
necessary
to
ensure
compliance.
The
schedule
in
today's
rule
provides
more
time
for
planning,
reviewing,
and
conducting
the
IDSE
than
the
schedule
in
the
proposed
rule,
which
will
allow
more
time
for
necessary
coordination,
including
small
consecutive
systems
that
need
help
in
negotiations
with
their
wholesale
system.
EPA
will
work
with
ASDWA
and
States
to
develop
guidance
to
facilitate
wholesale/
consecutive
system
cooperation.
This
additional
time
and
the
staggered
schedule
discussed
in
this
section
also
lessens
the
laboratory
burden
associated
with
IDSE
monitoring.

The
staggered
schedule
also
helps
address
commenter
concerns
about
evaluating
combined
distribution
systems.
Other
commenters'
concerns
about
time
needed
for
developing
contracts
between
systems
and
for
planning,
funding,
and
implementing
treatment
changes
are
addressed
by
not
requiring
Stage
2
compliance
until
at
least
six
years
following
rule
promulgation.
102
F.
Initial
Distribution
System
Evaluation
(
IDSE)

1.
Today's
rule
Today's
rule
establishes
requirements
for
systems
to
perform
an
Initial
Distribution
System
Evaluation
(
IDSE).
The
IDSE
is
intended
to
identify
sample
locations
for
Stage
2
compliance
monitoring
that
represent
distribution
system
sites
with
high
DBP
concentrations.
Systems
will
develop
an
IDSE
plan,
collect
data
on
DBP
levels
throughout
their
distribution
system,
evaluate
these
data
to
determine
which
sampling
locations
are
most
representative
of
high
DBP
levels,
and
compile
this
information
into
a
report
for
submission
to
the
State
or
primacy
agency.
Systems
must
complete
one
IDSE
to
meet
the
requirements
of
today's
rule.

a.
Applicability.
This
requirement
applies
to
all
community
water
systems,
and
to
large
nontransient
noncommunity
water
systems
(
those
serving
at
least
10,000
people)
that
use
a
primary
or
residual
disinfectant
other
than
ultraviolet
light,
or
that
deliver
water
that
has
been
treated
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
light.
Systems
serving
fewer
than
500
people
are
covered
by
the
very
small
system
waiver
provisions
of
today's
rule
and
are
not
required
to
complete
an
IDSE
if
they
have
TTHM
and
HAA5
data
collected
under
the
Stage
1
DBPRSubpart
L.
Consecutive
systems
are
subject
to
the
IDSE
requirements
of
today's
rule.

Consecutive
systems
must
comply
with
IDSE
requirements
on
the
same
schedule
as
the
system
serving
the
largest
population
in
the
combined
distribution
system,
as
described
in
section
IV.
E.

b.
Data
collection.
For
those
systems
not
receiving
a
very
small
system
waiver,
there
are
three
possible
approaches
by
which
a
system
can
meet
the
IDSE
requirement.

i.
Standard
monitoring.
Standard
monitoring
requires
one
year
of
DBP
monitoring
throughout
the
distribution
system
on
a
specified
schedule.
Prior
to
commencing
standard
monitoring,
systems
must
prepare
a
monitoring
plan
and
submit
it
to
the
primacy
agency
for
review.
The
frequency
and
number
of
samples
required
under
standard
monitoring
is
determined
103
by
source
water
type
and
system
size.
The
number
of
samples
does
not
depend
on
the
number
of
plants
per
system.
Section
IV.
G
provides
a
detailed
discussion
of
the
specific
population­
based
monitoring
requirements
for
IDSE
standard
monitoring.
Although
standard
monitoring
results
are
not
to
be
used
for
determining
compliance
with
MCLs,
systems
are
required
to
report
the
range
of
IDSE
results
in
theinclude
individual
sample
results
for
the
IDSE
results
when
determining
the
range
of
TTHM
and
HAA5
levels
to
be
reported
in
their
Consumer
Confidence
Report
(
see
section
IV.
J).

ii.
System
specific
study.
Under
this
approach,
systems
may
choose
to
perform
a
system
specific
study
based
on
earlier
monitoring
studies
or
distribution
system
hydraulic
models
in
lieu
of
standard
monitoring.
Prior
to
commencing
a
system
specific
study,
systems
must
prepare
a
study
plan
and
submit
it
to
the
primacy
agency
for
approval.
The
two
options
for
system
specific
studies
are:
(
1)
TTHM
and
HAA5
monitoring
data
that
encompass
a
wide
range
of
sample
sites
representative
of
the
entire
distribution
system,
including
those
judged
to
represent
high
TTHM
and
HAA5
concentrations,
and
(
2)
extended
period
simulation
hydraulic
models
that
simulate
water
age
in
the
distribution
system,
in
conjunction
with
one
round
of
TTHM
and
HAA5
sampling.

iii.
40/
30
certification.
Under
this
approach,
systems
must
certify
to
their
State
or
primacy
agency
that
all
required
Stage
1
DBPR
compliance
samples
were
properly
collected
and
analyzed
during
the
two
years
prior
to
the
start
of
the
IDSE,
and
allevery
individual
compliance
samplessample
taken
under
subpart
L
during
the
period
specified
in
Table
IV.
F­
2
were
less
than
or
equal
to
0.040
mg/
L
for
TTHM
and
less
than
or
equal
to
0.030
mg/
L
for
HAA5,
and
that
there
were
no
TTHM
or
HAA5
monitoring
violations
during
the
same
period.
The
State
or
primacy
agency
may
require
systems
to
submit
compliance
monitoring
results,
distribution
system
schematics,
or
recommend
subpart
V
compliance
monitoring
locations
as
part
of
the
certification.
104
This
certification
must
be
kept
on
file
and
submitted
to
the
State
or
primacy
agency
for
review.

Systems
that
qualify
for
reduced
monitoring
for
the
Stage
1
DBPR
during
the
two
years
prior
to
the
start
of
the
IDSE
may
use
results
of
reduced
Stage
1
DBPR
monitoring
to
prepare
the
40/
30
certification.
The
requirements
for
the
40/
30
certification
are
listed
in
Table
IV.
F­
1.

TABLE
IV.
F­
1.
40/
30
Certification
Requirements
40/
30
Certification
Requirements
C
A
certification
that
all
required
compliance
samples
were
properly
collected
and
analyzed
during
the
two
years
prior
to
the
start
of
the
IDSE
and
allevery
individual
compliance
samples
were
#
0sample
taken
under
subpart
L
during
the
period
specified
in
Table
IV.
F­
2
were
less
than
or
equal
to
0.040
mg/
L
for
TTHM
and
#
0less
than
or
equal
to
0.030
mg/
L
for
HAA5,
and
that
there
were
no
TTHM
or
HAA5
monitoring
violations
during
the
same
period.

C
Compliance
monitoring
results,
distribution
system
schematics,
and/
or
recommended
subpart
V
compliance
monitoring
locations
as
required
by
the
State
or
primacy
agency.
105
TABLE
IV.
F­
2.
40/
30
Eligibility
Dates.

If
your
40/
30
Certification
Is
Due
Then
your
eligibility
for
40/
30
certification
is
based
on
eight
consecutive
calendar
quarters
of
subpart
L
compliance
monitoring
results
beginning
no
earlier
than
1
(
1)
October
1,
2006
January
2004
(
2)
April
1,
2007
January
2004
(
3)
October
1,
2007
January
2005
(
4)
April
1,
2008
January
2005
1
Unless
you
are
on
reduced
monitoring
under
subpart
L
and
were
not
required
to
monitor
during
thisthe
specified
period(
1)
[
date
six
mos
following
publication
of
final
rule]
April
2004­
March
2006(
2)
[
date
12
mos
following
publication
of
final
rule]
October
2004­
September
2006(
3)
[
date
18
mos
following
publication
of
final
rule]
April
2005­
March
2007(
4)
[
date
24
mos
following
publication
of
final
rule]
October
2005­
September
2007.
If
you
did
not
monitor
during
the
specified
period,
you
must
base
your
eligibility
on
compliance
samples
taken
during
the
12
months
preceding
the
specified
period.

c.
Implementation.
All
systems
subject
to
the
IDSE
requirement
under
this
final
rule
(
except
those
covered
by
the
very
small
system
waiver)
must
prepare
and
submit
an
IDSE
plan
(
monitoring
plan
for
standard
monitoring,
study
plan
for
system
specific
study)
or
40/
30
certification
to
the
State
or
primacy
agency.
IDSE
plans
and
40/
30
certifications
must
be
submitted
according
to
the
schedule
described
in
section
IV.
E
and
IV.
M.
The
requirements
for
the
IDSE
plan
depend
on
the
IDSE
approach
that
the
system
selects
and
are
listed
in
Tables
IV.
F­

2F­
1
and
IV.
F­
3.
106
TABLE
IV.
F­
23.
IDSE
Monitoring
Plan
Requirements
IDSE
data
collection
alternative
IDSE
Plan
Requirements
Standard
Monitoring
C
Schematic
of
the
distribution
system
(
including
distribution
system
entry
points
and
their
sources,
and
storage
facilities),
with
notes
indicating
locations
and
dates
of
all
projected
standard
monitoring,
and
all
projected
subpart
L
compliance
monitoring
noted.

C
Justification
for
all
standard
monitoring
locations
selected
and
all
additional
summary
of
data
relied
on
to
select
those
locations.

C
Population
served
and
system
type
(
subpart
H
or
ground
water).
107
System
Specific
Study:
Hydraulic
Model
Hydraulic
models
must
meet
the
following
criteria:

C
Extended
period
simulation
hydraulic
model.

C
Simulate
24
hour
variation
in
demand
and
show
a
consistently
repeating
24
hour
pattern
of
residence
time.

C
Represent
75%
of
pipe
volume;
50%
of
pipe
length;
all
pressure
zones;
all
12­
inch
diameter
and
larger
pipes;
all
8
­
inches
and
larger
pipes
that
connect
pressure
zones,
influence
zones
from
different
sources,
storage
facilities,
major
demand
areas,
pumps,
and
control
valves,
or
are
known
or
expected
to
be
significant
conveyors
of
water;
all
pipes
6
inches
and
larger
that
connect
remote
areas
of
a
distribution
system
to
the
main
portion
of
the
system;
all
storage
facilities
with
standard
operations
represented
in
the
model;
all
active
pump
stations
with
controls
represented
in
the
model;
and
all
active
control
valves.

C
The
model
must
be
calibrated,
or
have
calibration
plans,
for
the
current
configuration
of
the
distribution
system
during
the
period
of
high
TTHM
formation
potential.
All
storage
facilities
must
be
evaluated
as
part
of
the
calibration
process.

C
All
required
calibration
must
be
completed
no
later
than
12
months
after
plan
submission.

Submission
must
include:

C
Tabular
or
spreadsheet
data
demonstrating
percent
of
total
pipe
volume
and
pipe
length
represented
in
the
model,
broken
out
by
pipe
diameter,
and
all
required
model
elements.

C
A
description
of
all
calibration
activities
undertaken,
includingand
if
calibration
is
complete,
a
graph
of
predicted
tank
levels
versus
measured
tank
levels
for
the
storage
facility
with
the
highest
residence
time
in
each
pressure
zone
(
if
calibration
is
complete),
and
a
time
series
graph
of
the
residence
time
at
the
longest
residence
time
storage
facility
in
the
distribution
system
showing
the
predictions
for
the
entire
EPS
simulation
period
(
i.
e.,
from
time
zero
until
the
time
it
takes
for
the
model
to
reach
a
consistently
repeating
pattern
of
residence
time).

C
Model
output
showing
preliminary
24
hour
average
residence
time
predictions
throughout
the
distribution
system.

C
Timing
and
number
of
samples
planned
for
at
least
one
round
of
TTHM
and
HAA5
monitoring
at
a
number
of
locations
no
less
than
would
be
required
for
the
system
under
standard
monitoring
in
§
141.601
during
the
historical
month
of
high
TTHM.
These
samples
must
be
taken
at
locations
other
than
existing
subpart
L
compliance
monitoring
locations.

C
Description
of
how
all
requirements
will
be
completed
no
later
than
12
months
after
you
submit
yoursubmission
of
the
system
specific
study
plan.

C
Schematic
of
the
distribution
system
(
including
distribution
system
entry
points
and
their
sources,
and
storage
facilities),
with
notes
indicating
the
locations
and
dates
of
all
completed
system
specific
study
monitoring
(
if
calibration
is
complete)
and
all
subpart
L
compliance
monitoring.

C
Population
served
and
system
type
(
subpart
H
or
ground
water).

C
If
the
model
submitted
does
not
fully
meet
the
requirements,
the
system
must
correct
the
deficiencies
and
respond
to
State
inquiries
on
a
schedule
the
State
approves,
or
conduct
standard
monitoring.
108
System
Specific
Study:
Existing
Monitoring
Results
Existing
monitoring
results
must
meet
the
following
criteria:

C
TTHM
and
HAA5
results
must
be
based
on
samples
collected
and
analyzed
in
accordance
with
§
141.131.
Samples
must
be
collected
within
five
years
of
the
study
plan
submission
date.

C
The
sampling
locations
and
frequency
must
meet
the
requirements
identified
in
tTable
IV.
F­
34.
Each
location
must
be
sampled
once
during
the
month
of
highest
TTHM
or
highestpeak
historical
month
for
TTHM
levels
or
HAA5
levels
or
the
month
of
warmest
water
temperature
for
every
12
months
of
data
submitted
for
that
location.
Monitoring
results
must
include
all
subpart
L
compliance
monitoring
results
plus
additional
monitoring
results
as
necessary
to
meet
minimum
sample
requirements.

Submission
must
include:

C
Previously
collected
monitoring
results
C
Certification
that
the
reported
monitoring
results
include
all
compliance
and
non­
compliance
results
generated
during
the
time
period
beginning
with
the
first
reported
result
and
ending
with
the
most
recent
subpart
L
results.

C
Certification
that
the
samples
were
representative
of
the
entire
distribution
system
and
that
treatment,
and
distribution
system
have
not
changed
significantly
since
the
samples
were
collected.

C
Schematic
of
the
distribution
system
(
including
distribution
system
entry
points
and
their
sources,
and
storage
facilities),
with
notes
indicating
the
locations
and
dates
of
all
completed
or
planned
system
specific
study
monitoring.

C
Population
served
and
system
type
(
subpart
H
or
ground
water).

C
If
a
system
submits
previously
collected
data
that
fully
meet
the
number
of
samples
required
for
IDSE
monitoring
in
Table
IV.
F­
34
and
some
of
the
data
are
rejected
due
to
not
meeting
the
additional
requirements,
the
system
must
either
conduct
additional
monitoring
to
replace
rejected
data
on
a
schedule
the
State
approves,
or
completeconduct
standard
monitoring.
109
Table
IV.
F­
34.
SSS
Existing
Monitoring
Data
Sample
Requirements.

System
Type
Population
Size
Category
Number
of
Monitoring
Locations
Number
of
Samples
TTHM
HAA5
Surface
Water
<
500
3
3
3
500­
3,300
3
9
9
3,301­
9,999
6
36
36
10,000­
49,999
12
72
72
50,000­
249,999
24
144
144
250,000­
999,999
36
216
216
1,000,000­
4,999,999
48
288
288
$
5,000,000
60
360
360
Ground
Water
<
500
3
3
3
500­
9,999
3
9
9
10,000­
99,999
12
48
48
100,000­
499,999
18
72
72
$
500,000
24
96
96
The
State
or
primacy
agency
will
approve
the
IDSE
plan
or
40/
30
certification,
or
request
modifications.
If
the
State
or
primacy
agency
has
not
taken
action
by
the
date
specified
in
section
IV.
E
or
has
not
notified
the
system
that
review
is
not
yet
complete,
systems
may
consider
their
submissions
to
be
approved.
Systems
must
implement
the
IDSE
option
described
in
the
IDSE
plan
approved
by
the
State
or
primacy
agency
according
to
the
schedule
described
in
section
IV.
E.

All
systems
completing
standard
monitoring
or
a
system
specific
study
must
submit
a
report
to
the
State
or
primacy
agency
according
to
the
schedule
described
in
section
IV.
E.

Systems
that
have
completed
their
system
specific
study
at
the
time
of
monitoring
plan
submission
may
submit
a
combined
monitoring
plan
and
report
on
the
required
schedule
for
monitoringIDSE
110
plan
submissions.
The
requirements
for
the
IDSE
report
are
listed
in
Table
IV.
F­
45.
Some
of
these
reporting
requirements
have
changed
from
the
proposal
to
reduce
reporting
and
paperwork
burden
on
systems.

TABLE
IV.
F­
45.
IDSE
Report
Requirements.

IDSE
data
collection
alternative
IDSE
report
requirements
Standard
Monitoring
C
All
subpart
L
compliance
monitoring
and
standard
monitoring
TTHM
and
HAA5
analytical
results
in
a
tabular
format
acceptable
to
the
State.

C
If
changed
from
the
standard
monitoring
plan,
a
schematic
of
the
distribution
system,
population
served,
and
system
type.

C
An
explanation
of
any
deviations
from
the
approved
monitoring
plan.

C
Recommendations
and
justifications
for
subpart
V
compliance
monitoring
locations
and
timing.

System
Specific
Study
C
All
subpart
L
compliance
monitoring
and
all
system
specific
study
monitoring
TTHM
and
HAA5
analytical
results
conducted
during
the
period
of
the
system
specific
study
in
a
tabular
or
spreadsheet
form
acceptable
to
the
State.

C
If
changed
from
the
system­
specific
study
plan,
a
schematic
of
the
distribution
system,
population
served,
and
system
type.

C
If
you
usedusing
the
modeling
provision,
you
must
include
final
calibration
information
for
required
plan
submissions
and
a
24­
hour
time
series
graph
of
residence
time
for
each
subpart
V
compliance
monitoring
location
selected.

C
An
explanation
of
any
deviations
from
the
original
study
plan.

C
All
analytical
results
and
modeling
results
used
to
select
subpart
V
compliance
monitoring
locations
and
an
analysis
showingthat
show
that
yourthe
system
specific
study
characterized
TTHM
and
HAA5
levels
throughout
yourthe
entire
distribution
system.

C
Recommendations
and
justifications
for
subpart
V
compliance
monitoring
locations
and
timing.

All
systems
must
prepare
Stage
2
compliance
monitoring
recommendations.
All
IDSE
reports
must
include
recommendations
for
Stage
2
compliance
monitoring
locations
and
sampling
schedule.
Systems
submitting
a
40/
30
certification
must
include
their
Stage
2
compliance
monitoring
recommendations
in
their
Stage
2
(
Subpart
V)
monitoring
plan
unless
the
State
requests
Subpart
V
site
recommendations
as
part
of
the
40/
30
certification.
The
number
of
sampling
locations
and
the
criteria
for
their
selection
are
described
in
§
141.605
of
today's
final
111
rule,
and
in
section
IV.
G.
Generally,
a
system
must
recommend
locations
with
the
highest
LRAAs
unless
it
provides
a
rationale
(
such
as
ensuring
geographical
coverage
of
the
distribution
system
instead
of
clustering
all
sites
in
a
particular
section
of
the
distribution
system)
for
selecting
other
locations.
In
evaluating
possible
Stage
2
compliance
monitoring
locations,
systems
must
consider
both
Stage
1
DBPR
compliance
data
and
IDSE
data.

The
State
or
primacy
agency
will
approve
the
IDSE
report
or
request
modifications.
If
the
State
or
primacy
agency
has
not
taken
action
by
the
date
specified
in
section
IV.
E
or
has
not
notified
the
system
that
review
is
not
yet
complete,
systems
may
consider
their
submission
to
be
approved
and
prepare
to
begin
Stage
2
compliance
monitoring.

EPA
has
developed
the
Initial
Distribution
System
Evaluation
Guidance
Manual
for
the
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
(
USEPA,
2005g6)
to
assist
systems
with
implementing
each
of
these
requirements.
This
guidance
may
be
requested
from
EPA's
Safe
Drinking
Water
Hotline,
which
may
be
contacted
as
described
under
FOR
"
FOR
FURTHER
INFORMATION
CONTACT"
in
the
beginning
of
this
notice.
This
guidance
manual
is
also
available
on
the
EPA
website
at
http://
www.
epa.
gov/
safewater/
XXXXgov/
safewater/
stage2/
index.
html.

2.
Background
and
analysis
In
the
Stage
2
DBPR
proposal
(
USEPA,
2003a),
EPA
proposed
requirements
for
systems
to
complete
an
IDSE.
The
Agency
based
its
proposal
upon
the
Stage
2
M­
DBP
Advisory
Committee
recommendations
in
the
Agreement
in
Principle.
The
Advisory
Committee
believed
and
EPA
concurs
that
maintaining
Stage
1
DBPR
monitoring
sites
for
the
Stage
2
DBPR
would
not
accomplish
the
risk­
targeting
objective
of
minimizing
high
DBP
levels
and
providing
consistent
and
equitable
protection
across
the
distribution
system.
Most
of
these
requirements
112
have
not
changed
from
the
proposed
rule.

The
data
collection
requirements
of
the
IDSE
are
designed
to
find
both
high
TTHM
and
high
HAA5
sites
(
see
section
IV.
G
for
IDSE
monitoring
requirements).
High
TTHM
and
HAA5
concentrations
often
occur
at
different
locations
in
the
distribution
system.
The
Stage
1
DBPR
monitoring
sites
identified
as
the
maximum
location
are
selected
according
to
residence
time.

HAAs
can
degrade
in
the
distribution
system
in
the
absence
of
sufficient
disinfectant
residual
(
Baribeau
et
al.
2000).
Consequently,
residence
time
is
not
an
ideal
criterion
for
identifying
high
HAA5
sites.
In
addition,
maximum
residence
time
locations
that
are
associated
with
high
TTHM
levels
may
not
be
constant
due
to
daily
or
seasonal
changes
in
demand.
The
analysis
of
maximum
residence
time
completed
for
the
selection
of
Stage
1
monitoring
sites
may
not
have
been
capable
of
detecting
these
variations.
The
Information
Collection
Rule
data
show
that
over
60
percent
of
the
highest
HAA5
LRAAs
and
50
percent
of
the
highest
TTHM
LRAAs
were
found
at
sampling
locations
in
the
distribution
system
other
than
the
maximum
residence
time
compliance
monitoring
location
(
USEPA
2003a).
Therefore,
the
method
and
assumptions
used
to
select
the
Information
Collection
Rule
monitoring
sites
and
the
Stage
1
DBPR
compliance
monitoring
sites
may
not
reliably
capture
high
DBP
levels
for
Stage
2
DBPR
compliance
monitoring
sites.

a.
Standard
monitoring.
The
Advisory
Committee
recommended
that
systems
sample
throughout
the
distribution
system
at
twice
the
number
of
locations
as
required
under
Stage
1
and,
using
these
results
in
addition
to
Stage
1
compliance
data,
identify
high
DBP
locations.

Monitoring
at
additional
sites
increases
the
chance
of
finding
sites
with
high
DBP
levels
and
targets
both
DBPs
that
degrade
and
DBPs
that
form
as
residence
time
increases
in
the
distribution
system.
EPA
believes
that
the
required
number
of
standard
monitoring
locations
plus
Stage
1
monitoring
results
will
provide
an
adequate
characterization
of
DBP
levels
throughout
the
distribution
system
at
a
reasonable
cost.
By
revising
Stage
2
compliance
monitoring
plans
to
113
target
locations
with
high
DBPs,
systems
will
be
required
to
take
steps
to
address
high
DBP
levels
at
locations
that
might
otherwise
have
gone
undetected.

The
Advisory
Committee
recommended
that
an
IDSE
be
performed
by
all
community
water
systems,
unless
the
system
had
sufficiently
low
DBP
levels
or
is
a
very
small
system
with
a
simple
distribution
system.
EPA
believes
that
large
nontransient
noncommunity
water
systems
(
NTNCWS)
(
those
serving
at
least
10,000
people)
also
have
distribution
systems
that
require
further
evaluation
to
determine
the
locations
most
representative
of
high
DBP
levels
and
proposed
that
they
be
required
to
conduct
an
IDSE.
Therefore,
large
NTNCWS
and
all
community
water
systems
are
required
to
comply
with
IDSE
requirements
under
today's
final
rule,
unless
they
submit
a
40/
30
certification
or
they
are
covered
by
the
very
small
system
waiver
provisions.

b.
Very
small
system
waivers.
Systems
serving
fewer
than
500
people
that
have
taken
samples
under
the
Stage
1
DBPR
will
receive
a
very
small
system
waiver.
EPA
proposed
and
the
Advisory
Committee
recommended
a
very
small
system
waiver
following
a
State
determination
that
the
existing
Stage
1
compliance
monitoring
location
adequately
characterizes
both
high
TTHM
and
high
HAA5
for
the
distribution
system
because
many
very
small
systems
have
small
or
simple
distribution
systems.
The
final
rule
grants
the
very
small
system
waiver
to
all
systems
serving
fewer
than
500
that
have
Stage
1
DBPR
data.
This
provision
was
changed
from
the
proposal
to
reflect
that
most
very
small
systems
that
sample
under
the
Stage
1
DBPR
have
sampling
locations
that
are
representative
of
both
high
TTHM
and
high
HAA5
because
most
very
small
systems
have
small
and
simple
distribution
systems.
In
addition,
many
very
small
systems
are
ground
water
systems
that
typically
have
stable
DBP
levels
that
tend
to
be
lower
than
surface
water
DBP
levels.
NRWA
survey
data
show
that
free
chlorine
residual
in
very
small
systems
(
serving
<
500)
at
both
average
residence
time
and
maximum
residence
time
locations
are
lower
than
levels
at
both
of
those
locations
in
larger
systems,
and
the
change
in
residual
concentration
114
between
those
two
locations
is
smaller
in
very
small
systems
compared
to
larger
sized
systems.

The
magnitude
of
the
reduction
in
residual
concentration
gives
an
indication
of
how
much
disinfectant
has
reacted
to
form
DBPs,
including
TTHM
and
HAA5.
The
smaller
reduction
in
disinfectant
concentration
between
average
residence
time
and
maximum
residence
time
in
very
small
systems
compared
to
larger
systems
indicates
that
DBP
formation
potential
is
probably
lower
in
very
small
systems
compared
to
larger
systems,
and
the
likelihood
for
significant
DBP
variation
within
the
distribution
system
of
very
small
systems
is
low
if
the
distribution
system
is
small
and
not
complex.
However,
there
may
be
some
small
systems
with
extended
or
complex
distribution
systems
that
should
be
studied
further
to
determine
new
sampling
locations.
For
this
reason,
States
or
primacy
agencies
can
require
any
particular
very
small
system
to
conduct
an
IDSE.
Very
small
systems
subject
to
the
Stage
2
DBPR
that
do
not
have
a
Stage
1
compliance
monitoring
location
may
monitor
in
accordance
with
the
Stage
1
DBPR
provisions
to
be
eligible
for
this
waiver.

c.
40/
30
certifications.
Systems
that
certify
to
their
State
or
primacy
agency
that
all
compliance
samples
taken
in
the
two
yearsduring
eight
consecutive
calendar
quarters
prior
to
the
start
of
the
IDSE
were
#
0.040
mg/
L
TTHM
and
#
0.030
mg/
L
HAA5
are
not
required
to
collect
additional
DBP
monitoring
data
under
the
IDSE
requirements
as
long
as
the
system
has
no
DBPTTHM
or
HAA5
monitoring
violations.
These
criteria
were
developed
because
both
EPA
and
the
Advisory
Committee
determined
that
these
systems
most
likely
would
not
have
DBP
levels
that
exceed
the
MCLs.
Systems
must
have
qualifying
TTHM
and
HAA5
data
for
the
twoeight
consecutive
years
priorcalendar
quarters
according
to
submission
of
the
certificationschedule
in
Table
IV.
F­
2
to
be
eligible
for
this
option.
Systems
on
reduced
monitoring
that
did
not
monitor
during
the
specified
two
yeartime
period
may
use
data
from
the
prior
year
to
meet
the
40/
30
certification
criteria.
Systems
that
have
not
previously
conducted
115
Stage
1
DBPR
compliance
monitoring
may
begin
such
monitoring
to
collect
the
data
necessary
to
qualify
for
40/
30
certification.
The
certification
and
data
supporting
it
must
be
available
to
the
public
upon
request.

The
qualifying
time
period
for
the
40/
30
certification
has
changed
from
the
proposed
rule.

Under
the
proposed
rule,
the
rule
language
identified
a
specific
two
year
window
with
start
and
end
dates.
In
today's
final
rule,
the
qualifying
time
period
has
been
changed
to
"
eight
consecutive
calendar
quarters
of
subpart
L
compliance
monitoring
results
beginning
no
earlier
than..."
(
see
Table
IV.
F­
2).
This
change
was
made
so
that
systems
that
have
made
a
treatment
change
within
the
two
years
prior
to
rule
promulgation
and
have
collected
initial
data
that
meet
the
40/
30
criteria
might
have
the
opportunity
to
collect
eight
consecutive
quarters
of
qualifying
data
and
apply
for
a
40/
30
certification.
This
schedule
change
also
allows
systems
that
have
not
previously
monitored
under
Stage
1
an
opportunity
to
qualify
for
a
40/
30
certification.

Under
the
proposed
Stage
2
DBPR,
systems
that
missed
the
deadline
for
submitting
a
40/
30
certification
would
be
required
to
conduct
either
standard
monitoring
or
a
system
specific
study
even
if
the
system
otherwise
qualified
for
the
40/
30
certification.
Under
today's
final
rule,

systems
that
do
not
make
any
submission
by
the
IDSE
plan
submission
deadline
will
still
receive
a
violation,
but
may
submit
a
late
40/
30
certification
if
their
data
meet
the
requirements.
This
change
was
made
so
that
systems
and
primacy
agencies
do
not
spend
time
preparing
and
reviewing
standard
monitoring
plans
and
IDSE
reports
for
systems
with
a
low
likelihood
of
finding
high
TTHM
and
HAA5
levels.

The
reporting
requirements
for
this
provision
have
been
reduced
from
the
requirements
in
the
proposed
rulemaking.
In
the
proposal,
systems
qualifying
for
the
40/
30
certification
were
required
to
submit
all
qualifying
data
and
provide
recommendations
for
Stage
2
compliance
monitoring
locations.
The
final
rule
requires
systems
to
submit
a
certification
that
their
data
116
meets
all
the
requirements
of
the
40/
30
certification
and
to
include
their
Stage
2
compliance
monitoring
recommendations
in
their
Stage
2
monitoring
plan.
These
changes
were
made
to
reduce
the
reporting
burden
on
systems
that
qualify
for
the
40/
30
certification
and
to
maintain
consistency
with
monitoring
plan
requirements
under
the
Stage
1
DBPR.
This
approach
also
gives
systems
more
time
to
select
appropriate
monitoring
sites
for
Stage
2
compliance
monitoring.

The
State
or
primacy
agency
may
request
systems
to
submit
the
data,
a
distribution
system
schematic,
and/
or
recommendations
for
Stage
2
compliance
monitoring
as
part
of
the
40/
30
certification.
This
provision
was
included
to
facilitate
primacy
agency
review
of
40/
30
certifications;
the
additional
information
is
only
required
if
requested
by
the
primacy
agency.

d.
System­
specificSystem
specific
studies.
Advisory
Committee
members
recognized
that
some
systems
have
detailed
knowledge
of
their
distribution
systems
by
way
of
ongoing
hydraulic
modeling
and/
or
existing
widespread
monitoring
plans
(
beyond
that
required
for
compliance
monitoring)
that
would
provide
equivalent
or
superior
monitoring
site
selection
information
compared
to
standard
monitoring.
Therefore,
the
Advisory
Committee
recommended
that
such
systems
be
allowed
to
determine
new
monitoring
sites
using
system­
specific
data
such
as
hydraulic
model
results
or
historicalexisting
monitoring
data;
this
provision
remains
in
the
final
rule.
In
the
proposed
rule,
the
only
specification
for
SSSs
was
to
identify
monitoring
sites
that
would
be
equivalent
or
superior
to
those
identified
under
Standard
Monitoring.
The
final
rule
includes
more
specific
requirements
than
the
proposal
on
how
these
studies
should
be
completed.

These
changes
were
madeThe
requirements
in
the
final
rule
were
developed
to
be
consistent
with
the
proposal,
yet
more
specific
to
help
systems
better
understand
expectations
under
this
provision
and
lessen
the
chances
of
an
SSS
study
plan
not
being
approved.

The
new
modeling
requirements
were
developed
to
reflect
that
hydraulic
models
can
identify
representative
high
TTHM
monitoring
locations
by
predicting
hydraulic
residence
time
in
117
the
distribution
system.
Water
age
has
been
found
to
correlate
with
TTHM
formation
in
the
distribution
system.
Consequently,
for
this
system
specific
study
approach,
hydraulic
residence
time
predicted
by
the
model
is
used
as
a
surrogate
for
TTHM
formation
to
locate
appropriate
Stage
2
compliance
monitoring
locations.
To
predict
hydraulic
residence
time
in
the
distribution
system,
the
model
must
represent
most
of
the
distribution
system
and
must
have
been
calibrated
recently
and
appropriately
to
reflect
water
age
in
the
distribution
system.
Requirements
to
reflect
this
are
in
today's
rule.
All
storage
facilities
must
be
evaluated
for
the
calibration,
and
systems
using
this
option
must
submit
a
graph
of
predicted
tank
levels
versus
measured
tank
levels
for
the
storage
facility
with
the
highest
residence
time
in
each
pressure
zone.
These
calibration
requirements
are
focused
on
storage
facilities
because
they
are
the
largest
controlling
factor
for
water
age
in
the
distribution
system.
The
calibration
requirements
reflect
the
fact
that
the
purpose
of
the
model
is
to
predict
water
age.
ICR
data
show
that
HAA5
data
do
not
necessarily
correlate
well
with
water
age
(
USEPA
2003
proposal2003a).
Because
the
purpose
of
the
IDSE
is
to
locate
representative
high
locations
for
both
TTHM
and
HAA5,
one
round
of
monitoring
must
be
completed
at
potential
Stage
2
compliance
monitoring
locations
to
determine
appropriate
HAA5
monitoring
locations
during
the
historical
high
month
of
TTHM
concentrations.
The
number
of
locations
must
be
no
less
than
would
be
required
under
standard
monitoring.
These
new
Preliminary
average
residence
time
data
are
required
as
a
part
of
the
study
plan
for
systems
to
demonstrate
that
their
distribution
system
hydraulic
model
is
able
to
produce
results
for
water
age
throughout
the
distribution
system,
even
though
calibration
may
not
be
complete.

Systems
also
need
to
describe
their
plans
to
complete
the
modeling
requirements
within
12
months
of
submitting
the
study
plan.
These
last
two
requirements
were
developed
so
that
States
can
be
assured
that
systems
have
the
technical
capacity
to
complete
their
modeling
requirements
by
the
IDSE
report
deadline.
If
systems
cannot
demonstrate
that
they
are
in
a
position
to
118
complete
the
modeling
requirements
according
the
required
schedule,
they
will
be
required
to
complete
standard
monitoring.

All
new
modeling
requirements
were
added
to
help
systems
demonstrate
how
their
model
will
fulfill
the
purpose
and
requirements
of
the
IDSE
and
to
assist
primacy
agencies
with
approval
determinations.
The
reporting
requirements
associated
with
these
newreporting
requirements
were
developed
to
balance
the
needs
of
systems
to
demonstrate
that
they
have
fulfilled
the
requirements
and
the
needs
of
primacy
agency
reviewers
to
be
able
to
understand
the
work
completed
by
the
system.

TheEPA
has
specified
new
requirements
for
systems
completing
an
SSS
using
existing
monitoring
data
requirements
for
the
SSS
were
added
to
help
systems
understand
the
extent
of
historical
data
that
would
meet
the
requirements
of
the
IDSE.
The
number
of
required
sample
locations
and
samples
are
consistent
with
sampling
requirements
under
standard
monitoring
and
the
recommendations
made
by
the
Advisory
Committee.
The
Advisory
Committee
recommended
that
systems
completing
an
IDSE
sample
at
twice
the
number
of
sites
required
by
the
Stage
1
DBPR
in
addition
to
Stage
1
DBPR
sampling.
TBecause
the
number
of
required
Stage
1
DBPR
monitoring
locations
required
in
Table
IV.
F­
3
isvaries
within
each
population
category
under
the
Stage
1
plant­
based
monitoring
approach
(
since
systems
have
different
numbers
of
plants),
EPA
used
the
number
of
required
Standard
Monitoring
locations
plus
the
number
of
Stage
2
compliance
monitoring
locations
to
develop
minimum
requirements
for
the
use
of
existing
monitoring
data
for
the
SSS.
The
number
of
required
locations
and
samples
are
shown
in
Table
IV.
F­
4.
Systems
will
use
their
Stage
1
monitoring
results
plus
additional
non­
compliance
or
operational
samples
to
fulfill
these
requirements.
Small
systems
with
many
plants
may
have
been
collecting
a
disproportionate
number
of
samples
under
the
Stage
1
DBPR
compared
to
the
population
based
monitoring
requirements
presented
in
today's
rule
and
may
have
sufficient
119
historical
data
to
characterize
the
entire
distribution
system.
These
requirements
allow
those
systems
to
submit
an
SSS
based
on
existing
Stage
1
monitoring
results,
and
they
also
accommodate
systems
that
have
been
completing
additional
monitoring
throughout
the
distribution
system.

The
requirement
to
sample
during
the
historical
month
of
high
TTHM,
high
HAA5,
or
warmest
water
temperature
during
each
year
for
which
data
waswere
collected
was
added
to
maintain
consistency
with
the
standard
monitoring
requirements
where
each
location
must
be
sampled
one
time
during
the
peak
historical
month.
Samples
that
qualify
for
this
SSS
must
have
been
collected
within
five
years
of
the
study
plan
submission
date
and
must
reflect
the
current
configuration
of
treatment
and
the
distribution
system.
Five
years
was
selected
as
a
cut
off
for
eligible
data
so
that
all
data
submitted
would
be
reasonably
representative
of
current
source
water
conditions
and
DBP
formation
within
the
distribution
system.
Data
that
isare
older
may
not
reflect
current
DBP
formation
potential
in
the
distribution
system.
Five
years
prior
to
the
submission
of
the
study
plan
also
correlates
with
the
signing
of
the
Agreement
in
Principle
where
the
Advisory
Committee
made
the
recommendation
for
this
provision.
Systems
interested
in
using
this
provision
would
have
started
eligible
monitoring
after
the
agreement
was
signed.

Systems
that
submit
existing
monitoring
data
must
submit
all
Stage
1
sample
results
from
the
beginning
of
the
SSS
to
the
time
when
the
SSS
plan
is
submitted.
The
purpose
of
this
requirement
is
to
demonstrate
that
there
have
been
no
significant
changes
in
source
water
quality
since
the
first
samples
were
collected,
especially
if
all
existing
monitoring
results
were
taken
during
the
earliest
eligible
dates.
Again,
these
clarifications
were
made
so
that
systems
could
better
understand
the
extent
of
data
necessary
for
a
monitoring
plan
to
be
deemed
acceptable
and
be
confident
that
efforts
to
complete
an
SSS
would
be
found
acceptable
to
the
State
or
primacy
agency.
120
e.
Distribution
System
Schematics.
EPA
has
considered
security
concerns
that
may
result
from
the
requirement
for
systems
to
submit
a
distribution
system
schematic
as
part
of
their
IDSE
plan.
EPA
believes
that
the
final
rule
strikes
an
appropriate
balance
between
security
concerns
and
the
need
for
States
and
primacy
agencies
to
be
able
to
review
IDSE
plans.
EPA
has
developed
guidance
for
systems
on
how
to
submit
a
distribution
system
schematic
that
does
not
include
sensitive
information.

3.
Summary
of
major
comments
The
Agency
received
significant
comments
on
the
following
issues
related
to
the
proposed
IDSE
requirements:
waiver
limitations,
and
State
or
primacy
agency
review
of
IDSE
plans.

In
the
proposed
rule,
EPA
requested
comment
on
what
the
appropriate
criteria
should
be
for
States
or
primacy
agencies
to
grant
very
small
system
waivers.
Commenters
responded
with
a
wide
range
of
suggestions
including
support
for
the
proposal
as
written,
different
population
cutoffs
State
or
primacy
agency
discretion
on
what
system
size
should
qualify
for
the
waiver,
and
alternative
waiver
criteria
such
as
pipe
length
or
number
of
booster
stations.
There
was
no
consensus
among
the
commenters
on
what
changes
should
be
made
to
the
proposal
for
the
very
small
system
waiver
requirements.
EPA
did
not
change
the
population
cutoff
for
the
very
small
system
waiver
because
analysis
of
NRWA
survey
data
also
showed
that
systems
serving
fewer
than
500
had
different
residence
times
and
lower
free
chlorine
residual
concentrations
compared
to
other
population
categories,
indicating
that
larger
systems
have
different
DBP
formation
characteristics
compared
to
very
small
systems.
Some
of
the
suggested
changes
for
very
small
system
waiver
criteria
may
require
data
that
isare
not
readily
available
to
systems
(
such
as
pipe
length
in
service)
and
for
which
there
were
no
specific
criteria
proposed
or
recommended
by
the
commenters.
Implementation
of
subjective
very
small
system
waiver
criteria
would
result
in
reduced
public
health
protection
from
the
rule
by
allowing
higher
DBP
levels
to
go
undetected.
121
In
addition
to
addressing
the
very
small
system
waivers,
commenters
suggested
that
different
criteria
should
be
used
for
the
40/
30
certification,
such
as
higher
minimum
DBP
levels,

cut­
offs
of
40/
30
as
LRAAs
or
RAAs
rather
than
single
sample
maximums,
or
State
or
primacy
agency
discretion
on
which
systems
should
qualify
for
40/
30
certification.
There
was
no
consensus
among
the
commenters
on
what
changes
should
be
made
to
the
proposal
for
the
40/
30
certification
requirements.
EPA
did
not
change
the
requirements
for
the
40/
30
certification
eligibility
because
the
recommended
alternatives
were
not
technically
superior
to
the
requirements
of
the
proposed
rule.
Implementation
of
40/
30
criteria
using
an
LRAA
or
RAA
would
result
in
reduced
public
health
protection
from
the
rule
by
allowing
higher
DBP
levels
to
go
undetected.

EPA
did
change
the
eligibility
dates
and
reporting
requirements
for
the
40/
30
certification
to
reduce
the
systems'
reporting
burdenburden
on
the
system.
Under
today's
final
rule,
States
or
primacy
agencies
can
request
TTHM
and
HAA5
data
as
desired
for
a
more
in
depth
review
of
a
system's
qualifications.

Many
commenters
expressed
concern
over
the
implementation
schedule
for
the
IDSE.

Commenters
were
especially
concerned
that
IDSE
plans
would
be
developed
and
implemented
prior
to
State
primacy,
and
once
States
receive
primacy,
they
might
not
support
the
IDSE
plan
and
would
reject
the
results
of
the
completed
IDSE.
To
address
this
issue,
commenters
requested
the
opportunity
for
States
to
review
the
IDSE
plans
prior
to
systems
completing
their
IDSEs.
In
today's
rule
EPA
has
modified
the
compliance
schedule
for
the
Stage
2
DBPR
so
that
systems
have
the
opportunity
to
complete
their
IDSE
plan
and
have
it
reviewed
by
the
primacy
agency
prior
to
completing
the
IDSE
to
address
the
concern
that
States
or
primacy
agencies
may
reject
the
results
of
the
completed
IDSE.
The
changes
to
the
compliance
schedule
are
discussed
further
in
section
IV.
E.
122
G.
Monitoring
Requirements
and
Compliance
Determination
for
TTHM
and
HAA5
MCLs
EPA
is
finalizing
monitoring
requirements
under
a
population­
based
approach
described
in
this
section.
EPA
believes
the
population­
based
approach
will
provide
more
representative
high
DBP
concentrations
throughout
distribution
systems
than
would
plant­
based
monitoring,
is
equitable,
and
will
simplify
implementation
for
both
States
and
systems.
For
these
reasons,
EPA
believes
this
approach
is
more
appropriate
than
the
proposed
plant­
based
monitoring.
Detailed
discussion
of
the
two
approaches
is
presented
in
the
preamble
of
the
proposed
rule
(
USEPA
2003a)
and
EA
for
today's
rule
(
USEPA
2005a).

1.
Today's
Rule
Today's
rule
establishes
TTHM
and
HAA5
monitoring
requirements
for
all
systems
based
on
a
population­
based
monitoring
approach
instead
of
a
plant­
based
approach.
Under
the
population­
based
approach,
monitoring
requirements
are
based
solely
on
the
retail
population
served
and
the
type
of
source
water
used
and
not
influenced
by
the
number
of
treatment
plants
or
entry
points
in
the
distribution
system
as
in
previous
rules
(
i.
e.,
TTHM
Rule
(
USEPA
1979)
and
Stage
1
DBPR
(
USEPA
1998a)).

a.
IDSE
Monitoring.
All
systems
conducting
IDSE
standard
monitoring
must
collect
samples
during
the
peak
historical
month
for
DBP
levels
or
water
temperature;
this
will
determine
their
monitoring
schedule.
Table
IV.
G­
1
contains
the
IDSE
monitoring
frequencies
and
locations
for
all
source
water
and
size
category
systems.
Section
IV.
F
identifies
other
approaches
by
which
systems
can
meet
IDSE
requirements.
123
Table
IV.
G­
1.
IDSE
Monitoring
Frequencies
and
Locations
.

Source
Water
Type
Population
Size
Category
Monitoring
Periods
and
Frequency
of
Sampling
Distribution
System
Monitoring
Locations1
Total
per
monitoring
period
Near
Entry
Points
Average
Residence
Time
High
TTHM
Locations
High
HAA5
Locations
Subpart
H
<
500
consecutive
systems
one
(
during
peak
historical
month)
2
2
13
1
&

1
&

<
500
nonconsecutive
systems
2
&
&

1
1
500­
3,300
consecutive
systems
four
(
every
90
days)
2
1
&

1
&

500­
3,300
nonconsecutive
systems
2
&
&

1
1
3,301­
9,999
4
&

1
2
1
10,000­
49,999
six
(
every
60
days)
8
1
2
3
2
50,000­
249,999
16
3
4
5
4
250,000­
999,999
24
4
6
8
6
1,000,000­
4,999,999
32
6
8
10
8
$
5,000,000
40
8
10
12
10
Ground
Water
<
500
consecutive
systems
one
(
during
peak
historical
month)
2
2
13
1
&

1
&

<
500
nonconsecutive
systems
2
&
&

1
1
500­
9,999
four
(
every
90
days)
2
&
&

1
1
10,000­
99,999
6
1
1
2
2
100,000­
499,999
8
1
1
3
3
$
500,000
12
2
2
4
4
1
A
dual
sample
set
(
i.
e.,
a
TTHM
and
an
HAA5
sample)
must
be
taken
at
each
monitoring
location
during
each
monitoring
period.
2
The
peak
historical
month
is
the
month
with
the
highest
TTHM
or
HAA5
levels
or
the
warmest
water
temperature.
3
You
must
monitor
at
or
near
the
entry
point
if
you
are
a
consecutive
system.
If
you
are
not
a
consecutive
system,
you
must
monitor
at
a
high
HAA5
location.
124
b.
Routine
Stage
2
Compliance
Monitoring.
For
all
systems
conducting
either
standard
monitoring
or
a
system
specific
study,
initial
Stage
2
compliance
monitoring
locations
are
based
on
the
system's
IDSE
results,
together
with
an
analysis
of
a
system's
Stage
1
DBPR
compliance
monitoring
results.
Systems
receiving
40/
30
certification
or
a
very
small
system
waiver,
and
nontransient
noncommunity
water
systems
serving
<
10,000
not
required
to
conduct
an
IDSE,

base
Stage
2
initial
compliance
monitoring
locations
on
the
system's
Stage
1
DBPR
compliance
monitoring
results.
Some
of
these
systems
may
also
need
an
evaluation
of
distribution
system
characteristics
to
identify
additional
monitoring
locations,
if
required
by
the
transition
from
plantbased
monitoring
to
population­
based
monitoring.

Systems
recommend
Stage
2
monitoring
locations
generally
by
arraying
results
of
IDSE
standard
monitoring
(
or
system
specific
study
results)
and
Stage
1
compliance
monitoring
by
monitoring
location
(
from
highest
to
lowest
LRAA
for
both
TTHM
and
HAA5).
Using
the
protocol
in
§
141.605(
c)
of
today's
rule,
systems
then
select
the
required
number
of
locations.

Larger
systems
include
existing
Stage
1
monitoring
locations
in
order
to
be
able
to
have
historical
continuity
for
evaluating
how
changes
in
operations
or
treatment
affect
DBP
levels.
Systems
may
also
recommend
locations
with
lower
levels
of
DBPs
that
would
not
be
picked
up
by
the
protocol
if
they
provide
a
rationale
for
the
recommendation.
Examples
of
rationales
include
ensuring
better
distribution
system
or
population
coverage
(
not
having
all
locations
in
the
same
area)
or
maintaining
existing
locations
with
DBP
levels
that
are
nearly
as
high
as
those
that
would
otherwise
be
selected.
The
State
or
primacy
agency
will
review
these
recommendations
as
part
of
the
review
of
the
IDSE
report
submitted
by
systems
that
conducted
standard
monitoring
or
a
system
specific
study.

Table
IV.
G­
2
contains
the
routine
Stage
2
TTHM
and
HAA5
compliance
monitoring
requirements
for
all
systems
(
both
non­
consecutive
and
consecutive
systems),
as
well
as
the
125
protocol
for
Stage
2
compliance
monitoring
location
selection
in
the
IDSE
report.
Systems
that
do
not
have
to
submit
an
IDSE
report
(
those
receiving
a
40/
30
certification
or
very
small
system
waiver
and
nontransient
noncommunity
water
systems
serving
<
10,000
will)
must
conduct
Stage
2
compliance
monitoring
atas
indicated
in
the
"
Total
per
monitoring
period"
column
at
current
Stage
1
compliance
monitoring
locations,
unless
the
State
or
primacy
agency
specifically
directs
otherwise.
All
systems
are
then
required
to
maintain
and
follow
a
Stage
2
compliance
monitoring
plan.

Table
IV.
G­
2
contains
the
routine
Stage
2
TTHM
and
HAA5
compliance
monitoring
requirements
for
all
systems
(
both
non­
consecutive
and
consecutive
systems).

Table
IV.
G­
2.
Routine
Compliance
Monitoring
Frequencies
and
Locations.

Source
Water
Type
Population
Size
Category
Monitoring
Frequency
1
Distribution
System
Monitoring
Location
Total
per
monitoring
period
2
Highest
TTHM
Locations
Highest
HAA5
Locations
Existing
Subpart
L
Compliance
Locations
Subpart
H
<
500
per
year
2
2
1
1
&

500­
3,300
per
quarter
2
2
1
1
&

3,301­
9,999
per
quarter
2
1
1
&

10,000­
49,999
per
quarter
4
2
1
1
50,000­
249,999
per
quarter
8
3
3
2
250,000­
999,999
per
quarter
12
5
4
3
1,000,000­
4,999,999
per
quarter
16
6
6
4
$
5,000,000
per
quarter
20
8
7
5
Ground
Water
<
500
per
year
2
2
1
1
&

500­
9,999
per
year
2
1
1
&

10,000­
99,999
per
quarter
4
2
1
1
100,000­
499,999
per
quarter
6
3
2
1
$
500,000
per
quarter
8
3
3
2
1
All
systems
must
take
at
least
one
dual
sample
setmonitor
during
month
of
highest
DBP
concentrations.
2
Systems
on
quarterly
monitoring
must
take
dual
sample
sets
every
90
days
at
each
monitoring
location,
except
for
126
subpart
H
systems
serving
500­
3,300.
2
System
iss
on
annual
monitoring
and
subpart
H
systems
serving
500­
3,300
are
required
to
take
individual
TTHM
and
HAA5
samples
(
instead
of
a
dual
sample
set)
at
the
locations
with
the
highest
TTHM
and
HAA5
concentrations,
respectively.
Only
one
location
with
a
dual
sample
set
per
monitoring
period
is
needed
if
highest
TTHM
and
HAA5
concentrations
occur
at
the
same
location,
and
month,
if
monitored
annually).
127
Today's
rule
provides
States
the
flexibility
to
specify
alternative
Stage
2
compliance
monitoring
requirements
(
but
not
alternative
IDSE
monitoring
requirements)
for
multiple
consecutive
systems
in
a
combined
distribution
system.
As
a
minimum
under
such
an
approach,

each
consecutive
system
must
collect
at
least
one
sample
among
the
total
number
of
samples
required
for
the
combined
distribution
system
and
will
base
compliance
on
samples
collected
within
its
distribution
system.
The
consecutive
system
is
responsible
for
ensuring
that
required
monitoring
is
completed
and
the
system
is
in
compliance.
It
also
must
document
its
monitoring
strategy
as
part
of
its
subpart
V
monitoring
plan.

Consecutive
systems
not
already
conducting
disinfectant
residual
monitoring
under
the
Stage
1
DBPR
must
comply
with
the
monitoring
requirements
and
MRDLs
for
chlorine
and
chloramines.
States
may
use
the
provisions
of
§
141.134(
c)
to
modify
reporting
requirements.

For
example,
the
State
may
require
that
only
the
consecutive
system
distribution
system
point­

ofentry
disinfectant
concentration
be
reported
to
demonstrate
MRDL
compliance,
although
monitoring
requirements
may
not
be
reduced.

i.
Reduced
monitoring.
Systems
can
qualify
for
reduced
monitoring,
as
specified
in
Table
IV.
G­
3,
if
the
LRAA
at
each
location
is
#
0.040
mg/
L
for
TTHM
and
#
0.030
mg/
L
for
HAA5
based
on
at
least
one
year
of
monitoring
at
routine
compliance
monitoring
locations.
Systems
may
remain
on
reduced
monitoring
as
long
as
the
TTHM
LRAA
is
#
0.040
mg/
L
and
the
HAA5
LRAA
is
#
0.030
mg/
L
at
each
monitoring
location
for
systems
with
quarterly
reduced
monitoring.
If
the
LRAA
at
any
location
exceeds
either
0.040
mg/
L
for
TTHM
or
0.030
mg/
L
for
HAA5
or
if
the
source
water
annual
average
TOC
level,
before
any
treatment,
exceeds
4.0
mg/
L
at
any
of
the
system's
treatment
plants
treating
surface
water
or
ground
water
under
the
direct
influence
of
surface
water,
the
system
must
resume
routine
monitoring.
For
systems
with
annual
or
less
frequent
reduced
monitoring,
systems
may
remain
on
reduced
monitoring
as
long
as
each
128
TTHM
sample
is
#
0.060
mg/
L
and
each
HAA5
sample
is
#
0.045
mg/
L.
If
the
annual
(
or
less
frequent)
sample
at
any
location
exceeds
either
0.060
mg/
L
for
TTHM
or
0.045
mg/
L
for
HAA5,

or
if
the
source
water
annual
average
TOC
level,
before
any
treatment,
exceeds
4.0
mg/
L
at
any
treatment
plant
treating
surface
water
or
ground
water
under
the
direct
influence
of
surface
water,

the
system
must
resume
routine
monitoring.
129
Table
IV.
G­
3.
Reduced
monitoring
frequency.

Source
Water
Type
Population
Size
Category
Monitoring
Frequency
1
Distribution
System
Monitoring
Location
per
Monitoring
Period
Subpart
H
<
500
­
monitoring
may
not
be
reduced
500­
3,300
per
year
1
TTHM
and
1
HAA5
sample:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement;
1
dual
sample
set
per
year
if
the
highest
TTHM
and
HAA5
measurements
occurred
at
the
same
location
and
quarter.

3,301­
9,999
per
year
2
dual
sample
sets:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement
10,000­
49,999
per
quarter
2
dual
sample
sets
at
the
locations
with
the
highest
TTHM
and
highest
HAA5
LRAAs
50,000­
249,999
per
quarter
4
dual
sample
sets
­
at
the
locations
with
the
two
highest
TTHM
and
two
highest
HAA5
LRAAs
250,000­
999,999
per
quarter
6
dual
sample
sets
­
at
the
locations
with
the
three
highest
TTHM
and
three
highest
HAA5
LRAAs
1,000,000­
4,999,999
per
quarter
8
dual
sample
sets
­
at
the
locations
with
the
four
highest
TTHM
and
four
highest
HAA5
LRAAs
$
5,000,000
per
quarter
10
dual
sample
sets
­
at
the
locations
with
the
five
highest
TTHM
and
five
highest
HAA5
LRAAs
Ground
Water
<
500
every
third
year
1
TTHM
and
1
HAA5
sample:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement;
1
dual
sample
set
per
year
if
the
highest
TTHM
and
HAA5
measurements
occurred
at
the
same
location
and
quarter.

500­
9,999
per
year
1
TTHM
and
1
HAA5
sample:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement;
1
dual
sample
set
per
year
if
the
highest
TTHM
and
HAA5
measurements
occurred
at
the
same
location
and
quarter.

10,000­
99,999
per
year
2
dual
sample
sets:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement
100,000­
499,999
per
quarter
2
dual
sample
sets;
at
the
locations
with
the
highest
TTHM
and
highest
HAA5
LRAAs
Source
Water
Type
Population
Size
Category
Monitoring
Frequency
1
Distribution
System
Monitoring
Location
per
Monitoring
Period
130
$
500,000
per
quarter
4
dual
sample
sets
at
the
locations
with
the
two
highest
TTHM
and
two
highest
HAA5
LRAAs
1
Systems
on
quarterly
monitoring
must
take
dual
sample
sets
every
90
days.
131
ii.
Compliance
determination.
A
PWS
is
in
compliance
when
the
annual
sample
or
LRAA
of
quarterly
samples
is
less
than
or
equal
to
the
MCLs.
If
an
annual
sample
exceeds
the
MCL,
the
system
must
conduct
increased
(
quarterly)
monitoring
but
is
not
immediately
in
violation
of
the
MCL.
The
system
is
out
of
compliance
if
the
LRAA
of
the
quarterly
samples
for
the
past
four
quarters
exceeds
the
MCL.

Monitoring
and
MCL
violations
are
assigned
to
the
PWS
where
the
violation
occurred.

Several
examples
are
as
follows:

C
If
monitoring
results
in
a
consecutive
system
indicate
an
MCL
violation,
the
consecutive
systems
is
in
violation
because
it
has
the
legal
responsibility
for
complying
with
the
MCL
under
State/
EPA
regulations.
The
consecutive
system
may
set
up
a
contract
with
its
wholesale
system
that
details
water
quality
delivery
specifications.

C
If
a
consecutive
system
has
hired
its
wholesale
system
under
contract
to
monitor
in
the
consecutive
system
and
the
wholesale
system
fails
to
monitor,
the
consecutive
system
is
in
violation
because
it
has
the
legal
responsibility
for
monitoring
under
State/
EPA
regulations.

C
If
a
wholesale
system
has
a
violation
and
provides
that
water
to
a
consecutive
system,
the
wholesale
system
is
in
violation.
Whether
the
consecutive
system
is
in
violation
will
depend
on
the
situation.
The
consecutive
system
will
also
be
in
violation
unless
it
conducted
monitoring
that
showed
that
the
violation
was
not
present
in
the
consecutive
system.

2.
Background
and
Analysis
EPA
proposed
the
plant­
based
approach
for
all
systems
that
produce
some
or
all
of
their
finished
water
and
the
population­
based
monitoring
approach
for
systems
purchasing
all
of
their
finished
water
year­
round.
As
part
of
the
proposal,
EPA
presented
a
monitoring
cost
analysis
for
132
applying
this
approach
to
all
systems
in
the
Economic
Analysis
to
better
understand
the
impacts
of
using
the
population­
based
approach.

The
plant­
based
approach
was
adopted
from
the
1979
TTHM
rule
and
the
Stage
1
DBPR
and
was
derived
from
the
generally
valid
assumption
that,
as
systems
increase
in
size,
they
tend
to
have
more
plants
and
increased
complexity.
During
the
development
of
the
Stage
2
proposal,

EPA
identified
a
number
of
issues
associated
with
the
use
of
the
plant­
based
monitoring
approach.

These
included:
1)
plant­
based
monitoring
is
not
as
effective
as
population­
based
monitoring
in
targeting
locations
with
the
highest
risk;
2)
a
plant­
based
approach
can
result
in
disproportionate
monitoring
requirements
for
systems
serving
the
same
number
of
people
(
due
to
widely
varying
numbers
of
plants
per
system);
3)
it
cannot
be
adequately
applied
to
plants
or
consecutive
system
entry
points
that
are
operated
seasonally
or
intermittently
if
an
LRAA
is
used
for
compliance
due
to
complex
implementation
and
a
need
for
repeated
transactions
between
the
State
and
system
to
determine
whether
and
how
compliance
monitoring
requirements
may
need
to
be
changed;
4)

State
determinations
of
monitoring
requirements
for
consecutive
systems
would
be
complicated,

especially
in
large
combined
distribution
systems
with
many
connections
between
systems;
and
5)

systems
with
multiple
disinfecting
wells
would
have
to
conduct
evaluation
of
common
aquifers
in
order
to
avoid
taking
unnecessary
samples
for
compliance
(
if
they
did
not
conduct
such
evaluations
under
Stage
1).
EPA
requested
comment
on
two
approaches
to
address
these
issues:

1)
keep
the
plant­
based
monitoring
approach
and
add
new
provisions
to
address
specific
concerns;
and
2)
base
monitoring
requirements
on
source
water
type
and
population
served,
in
lieu
of
plant­
based
monitoring.

The
final
rule's
requirements
of
population­
based
monitoring
for
all
systems
are
based
on
improved
public
health
protection,
flexibility,
and
simplified
implementation.
For
determining
monitoring
requirements,
EPA's
objective
was
to
maintain
monitoring
loads
consistent
with
Stage
133
1
and
similar
to
monitoring
loads
proposed
for
Stage
2
under
a
plant­
based
approach,
using
a
population­
based
approach
to
facilitate
implementation,
better
target
high
DBP
levels,
and
protect
human
health.
This
leads
to
a
more
cost­
effective
characterization
of
where
high
levels
occur.

For
the
proposed
rule,
EPA
used
1995
CWSS
data
to
derive
the
number
of
plants
per
system
for
calculating
the
number
of
proposed
monitoring
sites
per
system.
During
the
comment
period,

2000
CWSS
data
became
available.
Compared
to
the
1995
CWSS,
the
2000
CWSS
contained
questions
more
relevant
for
determining
the
number
of
plants
in
each
system.
Based
on
2000
CWSS
data,
EPA
has
modified
the
number
of
monitoring
sites
per
system
for
several
categories
(
particularly
for
the
larger
subpart
H
systems)
to
align
the
median
population­
based
monitoring
requirements
with
the
median
monitoring
requirements
under
plant­
based
monitoring,
as
was
proposed.

EPA
also
believes
that
more
samples
are
necessary
to
characterize
larger
systems
(
as
defined
by
population)
than
for
smaller
systems.
This
progressive
approach
is
included
in
Table
IV.
G­
4.
As
system
size
increases,
the
number
of
samples
increases
to
better
reflect
the
hydraulic
complexity
of
these
systems.
While
the
national
monitoring
burden
under
the
population­
based
approach
is
slightly
less
than
under
a
plant­
based
approach,
some
larger
systems
with
few
plants
relative
to
system
population
will
take
more
samples
per
system
than
they
had
under
plant­
based
monitoring.
However,
EPA
believes
that
many
of
these
large
systems
with
few
plants
have
traditionally
been
undermonitored
(
as
noted
in
the
proposal).
Systems
with
more
plants
will
see
a
reduction
in
monitoring
(
e.
g.,
small
ground
water
systems
with
multiple
wells).

While
population­
based
monitoring
requirements
for
ground
water
systems
in
today's
rule
remain
the
same
as
those
in
the
proposed
rule,
the
final
rule
consolidates
ten
population
categories
for
subpart
H
systems
into
eight
categories
for
ease
of
implementation.
As
indicated
in
Table
IV.
G­
4,
EPA
has
gone
from
four
to
three
population
size
categories
for
smaller
subpart
H
134
systems
(
serving
fewer
than
5010,000
people)
and
the
ranges
have
been
modified
to
be
consistent
with
those
for
other
existing
rules
(
such
as
the
Lead
and
Copper
Rule).
This
change
will
reduce
implementation
transactional
costs.
For
medium
and
large
subpart
H
systems
(
serving
at
least
10,000
people),
EPA
has
gone
from
seven
categories
in
the
proposal
to
five
categories
in
final
rule.
The
population
groups
are
sized
so
that
the
ratio
of
maximum
population
to
minimum
population
for
each
of
the
categories
is
consistent.
EPA
believes
that
this
will
allow
most
systems
to
remain
in
one
population
size
category
and
maintain
the
same
monitoring
requirements
within
a
reasonable
range
of
population
variation
over
time.
In
addition,
it
assures
that
systems
within
a
size
category
will
not
have
disparate
monitoring
burdens
as
could
occur
if
there
were
too
few
categories.
Overall,
EPA
believes
that
the
population­
based
monitoring
approach
allows
systems
to
have
more
flexibility
to
designate
their
monitoring
sites
within
the
distribution
system
to
better
target
high
DBP
levels
and
is
more
equitable.

To
derive
the
number
of
monitoring
sites
for
IDSE
standard
monitoring,
EPA
doubled
the
number
of
routine
compliance
monitoring
sites
per
system
for
each
size
category.
This
is
consistent
with
the
advice
and
recommendations
of
the
M­
DBP
Advisory
Committee
for
the
IDSE.
EPA
has
developed
the
Initial
Distribution
System
Evaluation
Guidance
Manual
for
the
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
(
USEPA
2005g6)
to
assist
systems
in
choosing
IDSE
monitoring
locations,
including
criteria
for
selecting
monitoring.
135
Table
IV.
G­
4.
Comparison
of
Monitoring
Locations
per
System
for
Stage
2
Routine
Compliance
Monitoring
with
Plant­
Based
and
Population­

Based
Approaches.

Note:
To
determine
the
number
of
routine
compliance
monitoring
sites
per
population
category,
EPA
took
these
steps:
1)
maintaining
about
the
same
sampling
loads
in
the
nation
as
required
under
the
plant­
based
approach,
but
basing
on
population
rather
than
number
of
plants
to
better
target
high
DBP
levels
in
distribution
systems
and
facilitate
implementation;
2)
The
number
of
monitoring
sites
per
plant
under
the
plant­
based
approach
(
Column
B)
were
multiplied
by
the
number
of
plants
per
system
(
Columns
C
and
D)
to
calculate
the
number
of
monitoring
sites
per
system
under
the
plant­
based
approach
(
Columns
E
and
F
in
terms
of
median
and
mean,
respectively);
and
3)
The
number
of
monitoring
sites
per
system
under
the
population­
based
approach
were
derived
with
adjustments
to
keep
categories
consistent
and
to
maintain
an
even
incremental
trend
as
the
population
size
category
increases
(
Column
G).

Population
Category
Ratio
of
Maximum
Population
to
Minimum
Population
Number
of
Sampling
Periods
per
Year
Plant­
Based
Approach*
Number
of
Plants
per
System
(
Based
on
2000
CWSS
Data)
Calculated
Number
of
Sites
per
System
for
Plant­
Based
Approach
Number
of
Monitoring
Sites
per
System
for
Pop­
Based
Approach
#
Sites
per
Plant
Median
Mean
Based
on
Median
#

Plants
per
system
Based
on
Mean
#

Plants
per
system
A
B
C
D
E=
B*
C
F=
B*
D
G
<
500
­
1
1**
1
1.21
1
1.2
1**

500­
3,300
6.6
4
1**
1
1.22
1
1.2
1**

3,301­
9,999
3
4
2
1
1.56
2
3.1
2
10,000­

49,999
5
4
4
1
1.37
4
5.5
4
50,000­
249,999
5
4
4
1
1.83
4
7.3
8
250,000­

<
1
million
4
4
4
2
2.53
8
10.1
12
1
million­

<
5
million
5
4
4
4
3.62
16
14.5
16
>
5
million
­
4
4
4
4.33
16
17.3
20
*
As
in
the
proposal.

**
System
is
required
to
take
individual
TTHM
and
HAA5
samples
at
the
locations
with
the
highest
TTHM
and
HAA5
concentrations,
respectively,
if
highest
TTHM
and
HAA5
concentrations
do
not
occur
at
the
same
location.
136
3.
Summary
of
Major
Comments
EPA
received
significant
support
for
applying
the
population­
based
approach
to
all
systems.
EPA
also
received
comments
concerning
the
specific
requirements
in
a
population­
based
approach.

Excessive
Sampling
Requirements.
Several
commenters
believed
that
the
proposed
sampling
requirements
were
excessive
(
especially
in
the
larger
population
categories
for
subpart
H
systems)
and
that
some
individual
systems
would
be
required
to
sample
more
under
the
population­
based
approach
than
the
plant­
based
approach.
EPA
recognizes
that
a
small
fraction
of
systems
in
some
categories
will
have
to
take
more
samples
under
the
population­
based
approach
than
the
plant­
based
approach
because
their
number
of
plants
is
substantially
less
than
the
national
median
or
mean.
However,
the
number
of
samples
required
under
the
Stage
1
DBPR
for
these
systems
may
not
have
been
sufficient
to
determine
the
concentrations
of
DBPs
throughout
the
distribution
system
of
these
systems.
On
the
other
hand,
systems
with
many
plants
may
have
taken
excessive
samples
under
the
Stage
1
DBPR
that
were
not
necessary
to
appropriately
determine
DBP
levels
throughout
the
distribution
system.
Consequently,
the
total
number
of
samples
taken
nationally
will
be
comparable
to
the
Stage
1
DBPR,
but
will
better
target
DBP
risks
in
individual
distribution
systems.

Consecutive
systems.
Some
commenters
noted
that
a
consecutive
system
may
need
to
take
more
samples
than
its
associated
wholesale
system.
Under
today's
rule,
all
systems,

including
consecutive
systems,
must
monitor
based
on
retail
population
served.
Thus,
large
consecutive
systems
will
take
more
samples
than
a
smaller
wholesale
system.
The
populationbased
monitoring
approach
will
allow
the
samples
to
better
represent
the
DBP
concentrations
consumed
by
the
population
associated
with
the
sampling
locations
and
to
understand
the
DBP
concentrations
reaching
consumers.
There
is
also
a
provision
that
allows
States
to
specify
137
alternative
monitoring
requirements
for
a
consecutive
system
in
a
combined
distribution
system
(
40
CFR
142.16(
m)(
3)).
This
special
primacy
condition
allows
the
State
to
establish
monitoring
requirements
that
account
for
complicated
distribution
system
relationships,
such
as
where
neighboring
systems
buy
from
and
sell
to
each
other
regularly
throughout
the
year.
In
this
case,

water
may
pass
through
multiple
consecutive
systems
before
it
reaches
a
user.
Another
example
would
be
a
large
group
of
interconnected
systems
that
have
a
complicated
combined
distribution
system.
This
approach
also
allows
the
combined
distribution
system
to
concentrate
IDSE
and
Stage
2
monitoring
sites
in
the
system
with
the
highest
known
DBP
concentrations,
while
assigning
fewer
sample
sites
to
systems
with
low
DBP
concentrations.

Population
Size
Categories.
Some
commenters
recommended
fewer
population
categories
for
subpart
H
systems
(
those
using
surface
water
or
ground
water
under
the
direct
influence
of
groundsurface
water
as
a
source)
than
proposed
while
others
recommended
more.

Today's
rule
has
fewer
categories
than
proposed.
However,
EPA
believes
that
further
reduction
of
the
number
of
population
size
categories
will
not
reflect
the
fact
that
the
number
of
plants
and
complexity
of
distribution
systems
(
and
DBP
exposure)
tend
to
increase
as
the
population
served
increases.
As
a
result,
the
population
served
by
a
large
system
in
one
particular
category
would
receive
much
less
protection
from
the
DBP
risks
than
a
smaller
system
in
the
same
size
category.

On
the
other
hand,
too
many
categories
with
smaller
population
ranges
would
result
in
frequent
category
and
requirement
shifts
as
population
fluctuates.
Much
greater
implementation
effort
would
be
needed
for
those
systems
without
much
benefit
in
DBP
exposure
knowledge.

Population
Definition.
Some
commenters
supported
use
of
the
population
of
a
combined
distribution
system
(
i.
e.,
the
wholesale
and
consecutive
systems
should
be
considered
a
single
system
for
monitoring
purposes)
while
others
preferred
use
of
the
retail
population
for
each
individual
system
(
i.
e.,
wholesale
systems
and
consecutive
systems
are
considered
separately).
138
Today's
final
rule
uses
the
retail
population
for
each
individual
system.
EPA
chose
this
approach
for
today's
rule
because
of
the
complexity
involved
in
making
implementation
decisions
for
consecutive
systems.
Using
the
retail
population
to
determine
requirements
eases
the
complexity
by
specifying
minimum
system­
level
requirements;
simplicity
is
essential
for
meeting
the
implementation
schedule
in
today's
rule.
If
monitoring
requirements
were
determined
by
the
combined
distribution
system
population,
many
implementation
problems
would
occur.
Some
of
these
problems
would
have
the
potential
to
impact
public
health
protection.
For
example,
States
or
primacy
agencies
would
have
to
decide
how
to
allocate
IDSE
distribution
system
samples
(
where
and
how
much
to
monitor
in
individual
PWSs)
in
a
complicated
combined
distribution
system
with
many
systems,
multiple
sources,
multiple
treatment
plants,
and
varying
water
demand
and
with
limited
understanding
of
DBP
levels
throughout
the
combined
distribution
system.
This
would
have
to
happen
shortly
after
rule
promulgation
in
order
to
meet
the
schedule.
For
example,

some
consecutive
systems
buy
water
seasonally
(
in
times
of
high
water
demand)
or
buy
from
more
than
one
wholesale
system
(
with
the
volume
purchased
based
on
many
factors).
The
State
or
primacy
agency
would
find
it
difficult
to
properly
assign
a
limited
number
of
IDSE
monitoring
locations
(
especially
since
there
are
States
where
many
consecutive
systems
have
no
DBP
data)
to
adequately
reflect
DBP
levels
in
such
a
system,
as
well
as
throughout
the
combined
distribution
system.

EPA
believes
that
assigning
compliance
monitoring
requirements
appropriately
throughout
the
combined
distribution
system
requires
a
case­
by­
case
determination
based
on
factors
such
as
amount
and
percentage
of
finished
water
provided;
whether
finished
water
is
provided
seasonally,

intermittently,
or
full­
time;
and
improved
DBP
occurrence
information.
Since
the
IDSE
will
provide
improved
DBP
occurrence
information
throughout
the
combined
distribution
system,

States
may
consider
modifications
to
Stage
2
compliance
monitoring
requirements
for
consecutive
139
systems
on
a
case­
by­
case
basis
as
allowed
by
§
141.29
or
under
the
special
primacy
condition
at
§
142.16(
m)(
3)
by
taking
all
these
factors
into
consideration.
In
making
these
case­
by­
case
determinations,
the
State
will
be
able
to
use
its
system­
specific
knowledge,
along
with
the
IDSE
results,
to
develop
an
appropriate
monitoring
plan
for
each
system
within
the
combined
distribution
system
.

Changes
to
monitoring
plans.
Commenters
requested
more
specific
language
regarding
how
IDSE
and
Stage
2
monitoring
plans
should
be
updated
as
a
result
of
treatment
or
population
changes
in
the
distribution
system.
Changes
to
IDSE
plans
should
not
be
necessary
since
the
State
or
primacy
agency
will
have
reviewed
those
plans
shortly
before
the
system
must
conduct
the
IDSE
and
the
reviewed
plan
should
identify
such
issues.
EPA
provided
a
process
in
the
Stage
2
DBPR
proposal
for
updating
monitoring
plans
for
systems
that
have
significant
changes
to
treatment
or
in
the
distribution
system
after
they
complete
their
IDSE.
This
process
remains
in
today's
rule,
with
an
added
requirement
that
systems
must
consult
with
the
State
or
primacy
agency
to
determine
whether
the
changes
are
necessary
and
appropriate
prior
to
implementing
changes
to
their
Stage
2
monitoring
plan.

In
addition,
the
State
or
primacy
agency
may
require
a
system
to
revise
theirits
IDSE
plan,

IDSE
report,
or
Stage
2
monitoring
plan
at
any
time.
This
change
was
made
so
that
systems
could
receive
system­
specific
guidance
from
the
State
or
primacy
agency
on
the
appropriate
revisions
to
the
Stage
2
monitoring
plan.
Regulatory
language
regarding
changes
that
might
occur
is
not
appropriate
because
any
modifications
would
be
system­
specific
and
a
national
requirement
is
not
capable
of
addressing
these
system­
specific
issues.

H.
Operational
Evaluation
Requirements
initiated
by
TTHM
and
HAA5
Levels
A
system
that
is
in
full
compliance
with
the
Stage
2
DBPR
LRAA
MCL
may
still
have
140
individual
DBP
measurements
that
exceed
the
Stage
2
DBPR
MCLs,
since
compliance
is
based
on
individual
DBP
measurements
at
a
location
averaged
over
a
four­
quarter
period.
EPA
and
the
Advisory
Committee
were
concerned
about
to
these
higher
levels
of
DBPs.
This
concern
was
clearly
reflected
in
the
Agreement
in
Principle,
which
states,
"...
significant
excursions
of
DBP
levels
will
sometimes
occur,
even
when
systems
are
in
full
compliance
with
the
enforceable
MCL...".

Today's
final
rule
addresses
this
concern
by
requiring
systems
to
conduct
operational
evaluations
that
are
initiated
by
operational
evaluation
levels
identified
in
Stage
2
DBPR
compliance
monitoring
and
to
submit
an
operational
evaluation
report
to
the
State.

1.
Today's
rule
Today's
rule
defines
the
Stage
2
DBP
operational
evaluation
levels
that
require
systems
to
conduct
operational
evaluations.
The
Stage
2
DBP
operational
evaluation
levels
are
identified
using
the
system's
Stage
2
DBPR
compliance
monitoring
results.
The
operational
evaluation
levels
for
each
monitoring
location
are
determined
by
the
sum
of
the
two
previous
quarters'

TTHM
results
plus
twice
the
current
quarter's
TTHM
result,
at
onethat
location,
divided
by
4
to
determine
an
average
and
the
sum
of
the
two
previous
quarters'
HAA5
results
plus
twice
the
current
quarter's
HAA5
result,
at
onethat
location,
divided
by
4
to
determine
an
average.
If
the
average
TTHM
exceeds
0.080
mg/
L
at
any
monitoring
location
or
the
average
HAA5
exceeds
0.060
mg/
L
at
any
monitoring
location,
the
system
must
conduct
an
operational
evaluation
and
submit
a
written
report
of
the
operational
evaluation
to
the
State..
141
Operational
evaluation
levels
(
calculated
at
each
monitoring
location)

IF
(
Q1
+
Q2
+
2Q3)/
4
>
MCL,
then
the
system
must
conduct
an
operational
evaluation
where
Q
3
=
current
quarter
measurement
Q
2
=
previous
quarter
measurement
Q
1
=
quarter
before
previous
quarter
measurement
MCL=
Stage
2
MCL
for
TTHM
(
0.080
mg/
l)
or
Stage
2
MCL
for
HAA5
(
0.060
mg/
L)

The
operational
evaluation
includes
an
examination
of
system
treatment
and
distribution
operational
practices,
including
changes
in
sources
or
source
water
quality,
storage
tank
operations,
and
excess
storage
capacity,
that
may
contribute
to
high
TTHM
and
HAA5
formation.

Systems
must
also
identify
what
steps
could
be
considered
to
minimize
recurrence
of
the
DBP
levels
that
initiated
thefuture
operational
evaluation
as
part
of
the
evaluation
reportlevel
exceedences.
In
cases
where
the
system
can
identify
the
of
the
cause
of
DBP
levels
that
resulted
in
the
operational
evaluation,
based
on
factors
such
as
water
quality
data,
plant
performance
data,

and
distribution
system
configuration
the
system
may
request
and
the
State
may
allow
limiting
the
evaluation
to
the
identified
cause.
The
State
must
issue
a
written
determination
approving
limiting
the
scope
of
the
operational
evaluation.
The
system
must
submit
their
operational
evaluation
report
to
the
State
for
review
within
90
days
after
being
notified
of
the
analytical
result
that
initiates
the
operational
evaluation.
Requesting
approval
to
limit
the
scope
of
the
operational
evaluation
does
not
extend
the
schedule
(
90
days
after
notification
of
the
analytical
result)
for
submitting
the
operational
evaluation
report.

2.
Background
and
analysis
The
Stage
2
DBPR
proposal
outlined
three
components
of
the
requirements
for
significant
excursions
(
definition,
system
evaluation
and
excursion
report)..
In
response
to
public
comments,
142
the
term
"
significant
excursion"
has
been
replaced
by
the
term
"
operational
evaluation
level"
in
today's
rule.
The
evaluation
and
report
components
remain
the
same
as
those
outlined
in
the
proposed
rule
for
significant
excursions.
However,
the
scope
of
the
evaluation
and
report
components
of
the
operational
evaluation
has
also
been
modified
from
the
proposed
significant
excursion
evaluation
components
based
on
public
comments.

In
the
Stage
2
DBPR
proposal,
States
were
to
define
criteria
to
identify
significant
excursions
rather
than
using
criteria
defined
by
EPA.
Concurrent
with
the
Stage
2
DBPR
proposal,
EPA
issued
draft
guidance
(
USEPA
2003e)
for
systems
and
States
that
described
how
to
determine
whether
a
significant
excursion
has
occurred,
using
several
different
options.
The
rule
proposal
specifically
requested
public
comment
on
the
definition
of
a
significant
excursion,

whether
it
should
be
defined
by
the
State
or
nationally,
and
the
scope
of
the
evaluation.

After
reviewing
comments
on
the
Stage
2
DBPR
proposal,
EPA
determined
that
DBP
levels
initiating
an
operational
evaluation
should
be
defined
in
the
regulation
to
ensure
national
consistency.
Systems
were
concerned
with
the
evaluation
requirements
being
initiated
based
on
criteria
that
might
not
be
consistent
nationally.
Also,
many
States
believed
the
requirement
for
States
to
define
criteria
to
initiate
an
evaluation
would
be
difficult
for
States
to
implement.

Under
today's
rule,
EPA
is
defining
operational
evaluation
levels
with
an
algorithm
based
on
Stage
2
DBPR
compliance
monitoring
results.
These
operational
evaluation
levels
will
act
as
an
early
warning
for
a
possible
MCL
violation
in
the
following
quarter.
This
early
warning
is
accomplished
because
the
operational
evaluation
requirement
is
initiated
when
the
system
assumes
that
the
current
quarter's
result
is
repeated
and
that
this
will
result
in
an
MCL
violation.
This
early
identification
allows
the
system
to
act
to
prevent
the
violation.

Today's
rule
also
modifies
the
scope
of
an
operational
evaluation.
EPA
has
concluded
that
the
source
of
DBP
levels
that
would
initiate
an
operational
evaluation
can
potentially
be
143
linked
to
a
number
of
factors
that
extend
beyond
distribution
system
operations.
Therefore,
EPA
believes
that
evaluations
must
include
a
consideration
of
treatment
plant
and
other
system
operations
rather
than
limiting
the
operational
evaluation
to
the
only
the
distribution
system,
as
proposed.
Because
the
source
of
the
problem
could
be
associated
with
operations
in
any
of
these
system
components
(
or
more
than
one),
an
evaluation
that
provides
systems
with
valuable
information
to
evaluate
possible
modifications
to
current
operational
practices
(
e.
g.
water
age
management,
source
blending)
or
in
planning
system
modifications
or
improvements
(
e.
g.

disinfection
practices,
tank
modifications,
distribution
looping)
will
reduce
DBP
levels
initiating
an
operational
evaluation.
EPA
also
believes
that
State
review
of
operational
evaluation
reports
is
valuable
for
both
States
and
systems
in
their
interactions,
particularly
when
systems
may
be
in
discussions
with
or
requesting
approvals
from
the
State
for
system
improvements.
Timely
reviews
of
operational
evaluation
reports
will
be
valuable
for
States
in
reviewing
other
compliance
submittals
and
will
be
particularly
valuable
in
reviewing
and
approving
any
proposed
source,

treatment
or
distribution
system
modifications
for
a
water
system.
Under
today's
rule,
systems
must
submit
a
written
report
of
the
operational
evaluation
to
the
State
no
later
than
90
days
after
being
notified
of
the
DBP
analytical
result
initiating
an
operational
evaluation.
The
written
operational
evaluation
report
must
also
be
made
available
to
the
public
upon
request.

3.
Summary
of
major
comments
EPA
received
comments
both
in
favor
of
and
opposed
to
the
proposed
evaluation
requirements.
While
some
commenters
felt
that
the
evaluation
requirements
should
not
be
a
part
of
the
Stage
2
DBPR
until
there
was
more
information
regarding
potential
health
effects
correlated
to
specific
DBP
levels,
other
commenters
felt
that
the
existing
health
effects
data
were
sufficient
to
warrant
strengthening
the
proposed
requirements
for
an
evaluation.
Today's
final
rule
requirements
are
consistent
with
the
Agreement
in
Principle
recommendations.
144
Some
commenters
noted
that
health
effects
research
on
DBPs
is
insufficient
to
identify
a
level
at
which
health
effects
occur
and
were
concerned
that
the
proposed
significant
excursion
requirements
placed
an
emphasis
on
DBP
levels
that
might
not
be
warranted
rather
than
on
system
operational
issues
and
compliance
with
Stage
2
DBPR
MCLs.

Basis.
The
proposed
requirements
for
significant
excursion
evaluations
were
not
based
upon
health
effects,
but
rather
were
intended
to
be
an
indicator
of
operational
performance.
To
address
commenter's
concerns
and
to
emphasize
what
EPA
believes
should
initiate
a
comprehensive
evaluation
of
system
operations
that
may
result
in
elevated
DBP
levels
and
provide
a
proactive
procedure
to
address
compliance
with
Stage
2
DBP
LRAA
MCLs
,
EPA
has
replaced
the
term
"
significant
excursion"
used
in
the
Stage
2
DBPR
proposal
with
the
term
"
operational
evaluation
level"
in
today's
rule.

Definition
of
the
operational
evaluation
levels.
The
majority
of
commenters
stated
that
EPA
should
define
the
DBP
levels
initiating
an
operational
evaluation
(`
significant
excursion'
in
the
proposal)
in
the
regulation
to
ensure
national
consistency
rather
than
requiring
States
to
develop
their
own
criteria
(
as
was
proposed).
Commenters
suggested
several
definitions,

including
a
single
numerical
limit
and
calculations
comparing
previous
quarterly
DBP
results
to
the
current
quarter's
result.
Commenters
that
recommended
a
single
numerical
limit
felt
that
such
an
approach
was
justified
by
the
available
health
effects
information,
while
other
commenters
felt
available
heath
effects
information
did
not
support
a
single
numerical
limit.
Commenters
recommended
that
any
definition
be
easy
to
understand
and
implement.

EPA
agrees
with
commenter
preference
for
national
criteria
to
initiate
an
operational
evaluation.
The
DBP
levels
initiating
an
operational
evaluation
in
today's
rule
consider
routine
operational
variations
in
distribution
systems,
isare
simple
for
water
systems
to
calculate,
and
minimizes
the
implementation
burden
on
States.
They
also
provide
an
early
warning
to
help
145
identify
possible
future
MCL
violations
and
allow
the
system
to
take
proactive
steps
to
remain
in
compliance.
EPA
emphasizes,
as
it
did
in
the
proposal
and
elsewhere
in
this
notice,
that
health
effects
research
is
insufficient
to
identify
a
level
at
which
health
effects
occur,
and
thus
today's
methodology
for
initiating
operational
evaluation
is
not
based
upon
health
effects,
but
rather
is
intended
as
an
indicator
of
operational
performance.

Scope
of
an
evaluation.
Some
commenters
felt
that
the
scope
of
an
evaluation
initiated
by
locational
DBP
levels
should
be
limited
to
the
distribution
systems,
as
in
the
proposal.
Others
felt
that
the
treatment
processes
should
be
included
in
the
evaluation,
noting
that
these
can
be
significant
in
the
formation
of
DBPs.

The
Agency
agrees
with
commenters
that
treatment
processes
can
be
a
significant
factor
in
DBP
levels
initiating
an
operational
evaluation
and
that
a
comprehensive
operational
evaluation
should
address
treatment
processes.
In
cases
where
the
system
can
clearly
identify
the
cause
of
the
DBP
levels
initiating
an
operational
evaluation
(
based
on
factors
such
as
water
quality
data,

plant
performance
data,
distribution
system
configuration,
and
previous
evaluations)
the
State
may
allow
the
system
to
limit
the
scope
of
the
evaluation
to
the
identified
cause.
In
other
cases,
it
is
appropriate
to
evaluate
the
entire
system,
from
source
through
treatment
to
distribution
system
configuration
and
operational
practices.

Timing
for
completion
and
review
of
the
evaluation
report.
While
some
commenters
agreed
that
the
evaluation
report
should
be
reviewed
as
part
of
the
sanitary
survey
process
(
as
proposed),
many
commenters
felt
that
the
time
between
sanitary
surveys
(
up
to
five
years)

minimized
the
value
of
the
evaluation
report
in
identifying
both
the
causes
of
DBP
levels
initiating
an
operational
evaluation
and
in
possible
changes
to
prevent
recurrence.
Moreover,
a
number
of
commenters
felt
that
the
evaluation
report
was
important
enough
to
warrant
a
separate
submittal
and
State
review
rather
than
have
the
evaluation
report
compete
with
other
priorities
during
a
146
sanitary
survey.

The
Agency
agrees
that
completion
and
State
review
of
evaluation
reports
on
a
three
or
five
year
sanitary
survey
cycle,
when
the
focus
of
the
evaluation
is
on
what
may
happen
in
the
next
quarter,
would
allow
for
an
unreasonable
period
of
time
to
pass
between
the
event
initiating
the
operational
evaluation
and
completion
and
State
review
of
the
report.
This
would
diminish
the
value
of
the
evaluation
report
for
both
systems
and
States,
particularly
when
systems
may
be
in
discussions
with
or
requesting
approval
for
treatment
changes
from
States,
and
as
noted
above,

the
focus
of
the
report
is
on
what
may
occur
in
the
next
quarter.
EPA
believes
that
timely
reviews
of
evaluation
reports
by
States
is
important,
would
be
essential
for
States
in
understanding
system
operations
and
reviewing
other
compliance
submittals,
and
would
be
extremely
valuable
in
reviewing
and
approving
any
proposed
source,
treatment
or
distribution
system
modifications
for
a
water
system.
Having
the
evaluation
information
on
an
ongoing
basis
rather
than
a
delayed
basis
would
also
allow
States
to
prioritize
their
resources
in
scheduling
and
reviewing
particular
water
system
operations
and
conditions
as
part
of
any
on­
site
system
review
or
oversight.

Therefore,
today's
rule
requires
that
systems
complete
the
operational
evaluation
and
submit
the
evaluation
report
to
the
State
within
90
days
of
the
occurrence.

I.
MCL,
BAT,
and
Monitoring
for
Bromate
1.
Today's
rule
Today
EPA
is
confirming
that
the
MCL
for
bromate
for
systems
using
ozone
remains
at
0.010
mg/
L
as
an
RAA
for
samples
taken
at
the
entrance
to
the
distribution
system
as
established
by
the
Stage
1
DBPR.
Because
the
MCL
remains
the
same,
EPA
is
not
modifying
the
existing
bromate
BAT.
EPA
is
changing
the
criterion
for
a
system
using
ozone
to
qualify
for
reduced
bromate
monitoring
from
demonstrating
low
levels
of
bromide
to
demonstrating
low
levels
of
147
bromate.

2.
Background
and
analysis
a.
Bromate
MCL.
Bromate
is
a
principal
byproduct
from
ozonation
of
bromidecontaining
source
waters.
As
described
in
more
detail
in
the
Stage
2
DBPR
proposal
(
USEPA
2003a),
more
stringent
bromate
MCL
has
the
potential
to
decrease
current
levels
of
microbial
protection,
impair
the
ability
of
systems
to
control
resistant
pathogens
like
Cryptosporidium,
and
increase
levels
of
DBPs
from
other
disinfectants
that
may
be
used
instead
of
ozone.
EPA
considered
reducing
the
bromate
MCL
from
0.010
mg/
L
to
0.005
mg/
L
as
an
annual
average
but
concluded
that
many
systems
using
ozone
to
inactivate
microbial
pathogens
would
have
significant
difficulty
maintaining
bromate
levels
at
or
below
0.005
mg/
L.
In
addition,
because
of
the
high
doses
required,
the
ability
of
systems
to
use
ozone
to
meet
Cryptosporidium
treatment
requirements
under
the
LT2ESWTR
would
be
diminished
if
the
bromate
MCL
was
decreased
from
0.010
to
0.005
mg/
L;
higher
doses
will
generally
lead
to
greater
bromate
formation.
After
evaluation
under
the
risk­
balancing
provisions
of
section
1412(
b)(
5)
of
the
SDWA,
EPA
concluded
that
the
existing
MCL
was
justified.
EPA
will
review
the
bromate
MCL
as
part
of
the
six­
year
review
process
and
determine
whether
the
MCL
should
remain
at
0.010
mg/
L
or
be
reduced
to
a
lower
level.
As
a
part
of
that
review,
EPA
will
consider
the
increased
utilization
of
alternative
technologies,
such
as
UV,
and
whether
the
risk/
risk
concerns
reflected
in
today's
rule,

as
well
as
in
the
LT2ESWTR,
remain
valid.

b.
Criterion
for
reduced
bromate
monitoring.
Because
more
sensitive
bromate
methods
are
now
available,
EPA
is
requiring
a
new
criterion
for
reduced
bromate
monitoring.
In
the
Stage
1
DBPR,
EPA
required
ozone
systems
to
demonstrate
that
source
water
bromide
levels,
as
a
running
annual
average,
did
not
exceed
0.05
mg/
L.
EPA
elected
to
use
bromide
as
a
surrogate
for
bromate
in
determining
eligibility
for
reduced
monitoring
because
the
available
analytical
148
method
for
bromate
was
not
sensitive
enough
to
quantify
levels
well
below
the
bromate
MCL
of
0.010
mg/
L.

EPA
approved
several
new
analytical
methods
for
bromate
that
are
far
more
sensitive
than
the
existing
method
as
part
of
the
Methods
Update
Rtoday's
rule
(__
FR
___,
___
____)
(
USEPA
2005h).
Since
these
methods
can
measure
bromate
to
levels
of
0.001
mg/
L
or
lower,
EPA
is
replacing
the
criterion
for
reduced
bromate
monitoring
(
source
water
bromide
running
annual
average
not
to
exceed
0.05
mg/
L)
with
a
bromate
running
annual
average
not
to
exceed
0.0025
mg/
L.

In
the
past,
EPA
has
often
set
the
criterion
for
reduced
monitoring
eligibility
at
50%
of
the
MCL,
which
would
be
0.005
mg/
L.
However,
the
MCL
for
bromate
will
remain
at
0.010
mg/
L,

representing
a
risk
level
of
2x10(­
4)
(
higher
than
EPA's
usual
excess
cancer
risk
range
of
10(­
4)

to
10(­
6))
because
of
risk
tradeoff
considerations
(
USEPA
2003a).

EPA
believes
that
the
decision
for
reduced
monitoring
is
separate
from
these
risk
tradeoff
considerations.
Risk
tradeoff
considerations
influence
the
selection
of
the
MCL,
while
reduced
monitoring
requirements
are
designed
to
ensure
that
the
MCL,
once
established,
is
reliably
and
consistently
achieved.
Requiring
a
running
annual
average
of
0.0025
mg/
L
for
the
reduced
monitoring
criterion
allows
greater
confidence
that
the
system
is
achieving
the
MCL
and
thus
ensuring
public
health
protection.

3.
Summary
of
major
comments
Commenters
supported
both
the
retention
of
the
existing
bromate
MCL
and
the
modified
reduced
monitoring
criterion.

J.
Public
Notice
Requirements
1.
Today's
rule
149
Today's
rule
does
not
alter
existing
public
notification
language
for
TTHM,
HAA5
or
TOC,
which
are
listed
under
40
CFR
141.201­
141.210
(
Subpart
Q).

2.
Background
and
analysis
EPA
requested
comment
on
including
language
in
the
proposed
rule
concerning
potential
reproductive
and
developmental
health
effects.
EPA
believes
this
is
an
important
issue
because
of
the
large
population
exposed
(
58
million
women
of
child­
bearing
age;
USEPA
2005a)
and
the
number
of
studies
that,
while
not
conclusive,
point
towards
a
potential
risk
concern.
While
EPA
is
not
including
information
about
reproductive
and
developmental
health
effects
in
public
notices
at
this
time,
the
Agency
plans
to
reconsider
whether
to
include
this
information
in
the
future.
As
part
of
this
effort,
EPA
intends
to
support
research
to
assess
communication
strategies
on
how
to
best
provide
this
information.

The
responsibilities
for
public
notification
and
consumer
confidence
reports
rest
with
the
individual
system.
Under
the
Public
Notice
Rule
(
Part
141
subpart
Q)
and
Consumer
Confidence
Report
Rule
(
Part
141
subpart
O),
the
wholesale
system
is
responsible
for
notifying
the
consecutive
system
of
analytical
results
and
violations
related
to
monitoring
conducted
by
the
wholesale
system.
Consecutive
systems
are
required
to
conduct
appropriate
public
notification
after
a
violation
(
whether
in
the
wholesale
system
or
the
consecutive
system).
In
their
consumer
confidence
report,
consecutive
systems
must
include
results
of
the
testing
conducted
by
the
wholesale
system
unless
the
consecutive
system
conducted
equivalent
testing
(
as
required
in
today's
rule)
that
indicated
the
consecutive
system
was
in
compliance,
in
which
case
the
consecutive
system
reports
its
own
compliance
monitoring
results.

3.
Summary
of
major
comments
EPA
requested
and
received
many
comments
on
the
topic
of
including
public
notification
language
regarding
potential
reproductive
and
developmental
effects.
A
number
of
comments
150
called
for
including
reproductive
and
developmental
health
effects
language
to
address
the
potential
health
concerns
that
research
has
shown.
Numerous
comments
also
opposed
such
language
due
to
uncertainties
in
the
underlying
science
and
the
implications
such
language
could
have
on
public
trust
of
utilities.

EPA
agrees
on
the
importance
of
addressing
possible
reproductive
and
developmental
health
risks.
However,
given
the
uncertainties
in
the
science
and
our
lack
of
knowledge
of
how
to
best
communicate
frightening
and
undefined
risks,
a
general
statement
about
reproductive
and
developmental
health
effects
is
premature
at
this
time.
The
Agency
needs
to
understand
how
best
to
characterize
and
communicate
these
risks
and
what
to
do
to
follow
up
any
such
communication.
The
public
deserves
accurate,
timely,
relevant,
and
understandable
communication.
The
Agency
will
continue
to
follow
up
on
this
issue
with
additional
research,

possibly
including
a
project
to
work
with
stakeholders
to
assess
risk
communication
strategies.

Some
comments
also
suggested
leaving
the
choice
of
language
up
to
the
water
server.

EPA
believes
that
this
strategy
would
cause
undue
confusion
to
both
the
PWS
and
the
public.

Commenters
generally
agreed
that
both
wholesale
and
consecutive
systems
that
conduct
monitoring
be
required
to
report
their
own
analytical
results
as
part
of
their
CCRs.
One
commenter
requested
clarification
of
consecutive
system
public
notification
requirements
when
there
is
a
violation
in
the
wholesale
system
but
the
consecutive
system
data
indicates
that
it
meets
DBP
MCLs.

Although
EPA
requires
consecutive
systems
to
conduct
appropriate
public
notification
of
violations
(
whether
in
the
wholesale
or
consecutive
system),
there
may
be
cases
where
the
violation
may
only
affect
an
isolated
portion
of
the
distribution
system.
Under
the
public
notification
rule,
the
State
may
allow
systems
to
limit
distribution
of
the
notice
to
the
area
that
is
out
of
compliance
if
the
system
can
demonstrate
that
the
violation
occurred
in
a
part
of
the
151
distribution
system
that
is
"
physically
or
hydraulically
isolated
from
other
parts
of
the
distribution
system."
This
provision
remains
in
place.
As
for
a
consecutive
system
whose
wholesale
system
is
in
violation,
the
consecutive
system
is
not
required
to
conduct
public
notification
if
DBP
levels
in
the
consecutive
system
are
in
compliance.

K.
Variances
and
Exemptions
to
be
updated
UPON
COMPLETION
OF
AFFORDABILITY
DISCUSSIONS
WITH
OMB
1.
Today's
Rule
States
may
grant
variances
in
accordance
with
sections
1415(
a)
and
1415(
e)
of
the
SDWA
and
EPA's
regulations.
States
may
grant
exemptions
in
accordance
with
section
1416(
a)
of
the
SDWA
and
EPA's
regulations.

2.
Background
and
Analysis
a.
Variances.
The
SDWA
provides
for
two
types
of
variances
­
general
variances
and
small
system
variances.
Under
section
1415(
a)(
1)(
A)
of
the
SDWA,
a
State
that
has
primary
enforcement
responsibility
(
primacy),
or
EPA
as
the
primacy
agency,
may
grant
general
variances
from
MCLs
to
those
public
water
systems
of
any
size
that
cannot
comply
with
the
MCLs
because
of
characteristics
of
the
raw
water
sources.
The
primacy
agency
may
grant
general
variances
to
a
system
on
condition
that
the
system
install
the
best
technology,
treatment
techniques,
or
other
means
that
EPA
finds
available
and
based
upon
an
evaluation
satisfactory
to
the
State
that
indicates
that
alternative
sources
of
water
are
not
reasonably
available
to
the
system.
At
the
time
this
type
of
variance
is
granted,
the
State
must
prescribe
a
compliance
schedule
and
may
require
the
system
to
implement
additional
control
measures.
Furthermore,
before
EPA
or
the
State
may
grant
a
general
variance,
it
must
find
that
the
variance
will
not
result
in
an
unreasonable
risk
to
152
health
(
URTH)
to
the
public
served
by
the
public
water
system.
In
today's
final
rule,
EPA
is
specifying
BATs
for
general
variances
under
section
1415(
a)
(
see
section
IV.
D).

Section
1415(
e)
authorizes
the
primacy
agency
to
issue
variances
to
small
public
water
systems
(
those
serving
fewer
than
10,000
people)
where
the
primacy
agent
determines
(
1)
that
the
system
cannot
afford
to
comply
with
an
MCL
or
treatment
technique
and
(
2)
that
the
terms
of
the
variances
will
ensure
adequate
protection
of
human
health
(
63
FR
43833,
August
14,
1998)

(
USEPA
1998c).
These
variances
may
only
be
granted
where
EPA
has
determined
that
there
is
no
affordable
compliance
technology
and
has
identified
a
small
system
variance
technology
under
section
1412(
b)(
15)
for
the
contaminant,
system
size
and
source
water
quality
in
question.
As
discussed
below,
small
system
variances
under
section
1415(
e)
are
not
available
because
EPA
has
determined
that
affordable
compliance
technologies
are
available.

The
1996
Amendments
to
the
SDWA
identify
three
categories
of
small
public
water
systems
that
need
to
be
addressed:
(
1)
Those
serving
a
population
of
3301­
10,000;
(
2)
those
serving
a
population
of
500­
3300;
and
(
3)
those
serving
a
population
of
25­
499.
The
SDWA
requires
EPA
to
make
determinations
of
available
compliance
technologies
for
each
size
category.

A
compliance
technology
is
a
technology
that
is
affordable
and
that
achieves
compliance
with
the
MCL
and/
or
treatment
technique.
Compliance
technologies
can
include
point­
of­
entry
or
point­

ofuse
treatment
units.
Variance
technologies
are
only
specified
for
those
system
size/
source
water
quality
combinations
for
which
there
are
no
listed
affordable
compliance
technologies.

Using
its
current
National
Affordability
Criteria,
EPA
has
determined
that
multiple
affordable
compliance
technologies
are
available
for
each
of
the
three
system
sizes
(
USEPA
2005a),
and
therefore
did
not
identify
any
variance
treatment
technologies.
The
analysis
was
consistent
with
the
current
methodology
used
in
the
document
"
National­
Level
Affordability
Criteria
Under
the
1996
Amendments
to
the
Safe
Drinking
Water
Act"
(
USEPA
1998d)
and
the
153
"
Variance
Technology
Findings
for
Contaminants
Regulated
Before
1996"
(
USEPA
1998e).

However,
EPA
is
currently
reevaluating
its
national­
level
affordability
criteria
and
has
solicited
recommendations
from
both
the
NDWAC
and
the
SAB
as
part
of
this
review.
EPA
intends
to
apply
the
revised
criteria
to
the
Stage
2
DBPR
once
they
have
been
finalized
for
the
purpose
of
determining
whether
to
enable
States
to
give
variances.
Thus,
while
the
analysis
of
Stage
2
household
costs
will
not
change,
EPA's
determination
regarding
the
availability
of
affordable
compliance
technologies
for
the
different
categories
of
small
systems
may.

b.
Affordable
Treatment
Technologies
for
Small
Systems.
The
treatment
trains
considered
and
predicted
to
be
used
in
EPA's
compliance
forecast
for
systems
serving
under
10,000
people,

are
listed
in
Table
IV.
K­
1.

Table
IV.
K­
1.
Technologies
Considered
and
Predicted
to
be
used
in
Compliance
Forecast
for
Small
Systems.

SW
Water
Plants
GW
Water
Plants
°
Switching
to
chloramines
as
a
residual
disinfectant
°
Chlorine
dioxide
(
not
for
systems
serving
fewer
than
100
people)
°
UV
°
Ozone
(
not
for
systems
serving
fewer
than
100
people)
°
Micro­
filtration/
Ultra­
Filtration
°
GAC20
°
GAC20
+
Advanced
disinfectants
°
Integrated
Membranes
°
Switching
to
chloramines
as
a
residual
disinfectant
°
UV
°
Ozone
(
not
for
systems
serving
fewer
than
100
people)
°
GAC20
°
Nanofiltration
Note:
Italicized
technologies
are
those
predicted
to
be
used
in
the
compliance
forecast.
Source:
Exhibits
5.11b
and
5.14b,
USEPA
2005a.

The
household
costs
for
these
technologies
were
compared
against
the
EPA's
current
national­
level
affordability
criteria
to
determine
the
affordable
treatment
technologies.
The
Agency's
national
level
affordability
criteria
were
published
in
the
August
6,
1998
Federal
154
Register
(
USEPA
1998d).
A
complete
description
of
how
this
analysis
was
applied
to
Stage
2
DBPR
is
given
in
Section
8.3
of
the
Economic
Analysis
(
USEPA
2005a).

Of
the
technologies
listed
in
Table
IV.
K­
1,
integrated
membranes
with
chloramines,

GAC20
with
advanced
oxidants,
and
ozone
are
above
the
affordability
threshold
in
the
0
to
500
category.
No
treatment
technologies
are
above
the
affordability
threshold
in
the
500
to
3,300
category
or
the
3,300
to
10,000
category.
As
shown
in
the
Economic
Analysis
for
systems
serving
fewer
than
500
people,
14
systems
are
predicted
to
use
GAC20
with
advanced
disinfectants,
one
system
is
predicted
to
use
integrated
membranes,
and
no
systems
are
predicted
to
use
ozone
to
comply
with
the
Stage
2
DBPR
(
USEPA
2005a).
However,
several
alternate
technologies
are
affordable
and
likely
available
to
these
systems.
In
some
cases,
the
compliance
data
for
these
systems
under
the
Stage
2
DBPR
will
be
the
same
as
under
the
Stage
1
DBPR
(
because
many
systems
serving
fewer
than
500
people
will
have
the
same
single
sampling
site
under
both
rules);
these
systems
will
have
already
installed
the
necessary
compliance
technology
to
comply
with
the
Stage
1
DBPR.
It
is
also
possible
that
less
costly
technologies
such
as
those
for
which
percentage
use
caps
were
set
in
the
decision
tree
may
actually
be
used
to
achieve
compliance
(
e.
g.,
chloramines,
UV).
Thus,
EPA
believes
that
compliance
by
these
systems
will
be
affordable.

As
shown
in
Table
IV.
K­
2,
the
cost
model
predicts
that
some
households
served
by
very
small
systems
will
experience
household
cost
increases
greater
than
the
available
expenditure
margins
as
a
result
of
adding
advanced
technology
for
the
Stage
2
DBPR
(
USEPA
2005a).
This
prediction
may
be
overestimated
because
small
systems
may
have
other
compliance
alternatives
available
to
them
besides
adding
treatment,
which
were
not
considered
in
the
model.
For
example,
some
of
these
systems
currently
may
be
operated
on
a
part­
time
basis;
therefore,
they
may
be
able
to
modify
the
current
operational
schedule
or
use
excessive
capacity
to
avoid
155
installing
a
costly
technology
to
comply
with
the
Stage
2
DBPR.
The
system
also
may
identify
another
water
source
that
has
lower
TTHM
and
HAA5
precursor
levels.
Systems
that
can
identify
such
an
alternate
water
source
may
not
have
to
treat
that
new
source
water
as
intensely
as
their
current
source,
resulting
in
lower
treatment
costs.
Systems
may
elect
to
connect
to
a
neighboring
water
system.
While
connecting
to
another
system
may
not
be
feasible
for
some
remote
systems,
EPA
estimates
that
more
than
22
percent
of
all
small
water
systems
are
located
within
metropolitan
regions
(
USEPA
2000f)
where
distances
between
neighboring
systems
will
not
present
a
prohibitive
barrier.
Low­
cost
alternatives
to
reduce
total
trihalomethanes
(
TTHM)

and
haloacetic
acid
(
HAA5)
levels
also
include
distribution
system
modifications
such
as
flushing
distribution
mains
more
frequently,
looping
to
prevent
dead
ends,
and
optimizing
storage
to
minimize
retention
time.
More
discussion
of
household
cost
increases
is
presented
in
Section
VI.
E
and
the
Economic
Analysis
(
USEPA
2005a).
156
Systems
Size
(
population
served)
Number
of
Households
Served
by
Plants
Adding
Treatment
(
Percent
of
all
Households
Subject
to
the
Stage
2
DBPR)
Mean
Annual
Household
Cost
Increase
Median
Annual
Household
Cost
Increase
90th
Percentile
Annual
Household
Cost
Increase
95th
Percentile
Annual
Household
Cost
Increase
Available
Expenditure
Margin
($/
hh/
yr)
Number
of
Households
with
Annual
Cost
Increases
Greater
then
the
Available
Expenditure
Margin
Number
of
Surface
Water
Plants
with
Annual
Cost
Increases
Greater
than
the
Available
Expenditure
Margin
Number
of
Groundwater
Plants
with
Annual
Cost
Increases
Greater
than
the
Available
Expenditure
Margin
Total
Number
of
Plants
with
Annual
Cost
Increases
Greater
than
the
Available
Expenditure
Margin
A
B
C
D
E
F
G
H
I
J
=
H
+
I
0
­
500
43045
(
3%
)
$
201.55
$
299.01
$
299.01
$
414.74
$
733
964
15
0
15
501
­
3,300
205842
(
4%
)
$
58.41
$
29.96
$
75.09
$
366.53
$
724
0
0
0
0
3,301
­
10,000
342525
(
5%
)
$
37.05
$
14.59
$
55.25
$
200.05
$
750
0
0
0
0
Table
IV.
K­
2.
Distribution
of
Household
Unit
Treatment
Costs
for
Plants
Adding
Treatment.

Notes:
Household
unit
costs
represent
treatment
costs
only.
All
values
in
year
2003
dollars.

Source:
Exhibit
8.4c,
USEPA
2005a.
157
c.
Exemptions.
Under
section
1416(
a),
EPA
or
a
State
that
has
primary
enforcement
responsibility
(
primacy)
may
exempt
a
public
water
system
from
any
requirements
related
to
an
MCL
or
treatment
technique
of
an
NPDWR,
if
it
finds
that
(
1)
due
to
compelling
factors
(
which
may
include
economic
factors
such
as
qualification
of
the
PWS
as
serving
a
disadvantaged
community),
the
PWS
is
unable
to
comply
with
the
requirement
or
implement
measures
to
develop
an
alternative
source
of
water
supply;
(
2)
the
exemption
will
not
result
in
an
unreasonable
risk
to
health;
and;
(
3)
the
PWS
was
in
operation
on
the
effective
date
of
the
NPDWR,
or
for
a
system
that
was
not
in
operation
by
that
date,
only
if
no
reasonable
alternative
source
of
drinking
water
is
available
to
the
new
system;
and
(
4)
management
or
restructuring
changes
(
or
both)

cannot
reasonably
result
in
compliance
with
the
Act
or
improve
the
quality
of
drinking
water.
If
EPA
or
the
State
grants
an
exemption
to
a
public
water
system,
it
must
at
the
same
time
prescribe
a
schedule
for
compliance
(
including
increments
of
progress
or
measures
to
develop
an
alternative
source
of
water
supply)
and
implementation
of
appropriate
control
measures
that
the
State
requires
the
system
to
meet
while
the
exemption
is
in
effect.
Under
section
1416(
b)(
2)(
A),
the
schedule
prescribed
shall
require
compliance
as
expeditiously
as
practicable
(
to
be
determined
by
the
State),
but
no
later
than
3
years
after
the
effective
date
for
the
regulations
established
pursuant
to
section
1412(
b)(
10).
For
public
water
systems
which
do
not
serve
more
than
a
population
of
3,300
and
which
need
financial
assistance
for
the
necessary
improvements,
EPA
or
the
State
may
renew
an
exemption
for
one
or
more
additional
two­
year
periods,
but
not
to
exceed
a
total
of
6
years,
if
the
system
establishes
that
it
is
taking
all
practicable
steps
to
meet
the
requirements
above.
A
public
water
system
shall
not
be
granted
an
exemption
unless
it
can
establish
that
either:

(
1)
the
system
cannot
meet
the
standard
without
capital
improvements
that
cannot
be
completed
prior
to
the
date
established
pursuant
to
section
1412(
b)(
10);
(
2)
in
the
case
of
a
system
that
needs
financial
assistance
for
the
necessary
implementation,
the
system
has
entered
into
an
158
agreement
to
obtain
financial
assistance
pursuant
to
section
1452
or
any
other
Federal
or
state
program;
or
(
3)
the
system
has
entered
into
an
enforceable
agreement
to
become
part
of
a
regional
public
water
system.

3.
Summary
of
major
comments
Several
commenters
agreed
with
the
proposal
not
to
list
variances
technologies
for
the
Stage
2
DBPR.
One
commenter
requested
that
EPA
modify
the
methodology
used
to
assess
affordability.
As
mentioned
earlier,
EPA
is
currently
reevaluating
its
national­
level
affordability
criteria
and
has
solicited
recommendations
from
both
the
NDWAC
and
the
SAB
as
part
of
this
review.
EPA
intends
to
apply
the
revised
criteria
to
the
Stage
2
DBPR
for
the
purpose
of
determining
whether
to
enable
States
to
give
variances.

L.
Requirements
for
Systems
to
Use
Qualified
Operators
EPA
believes
that
systems
that
must
make
treatment
changes
to
comply
with
requirements
to
reduce
microbiological
risks
and
risks
from
disinfectants
and
disinfection
byproducts
should
be
operated
by
personnel
who
are
qualified
to
recognize
and
respond
to
problems.
Subpart
H
systems
were
required
to
be
operated
by
qualified
operators
under
the
SWTR
(
§
141.70).
The
Stage
1
DBPR
added
requirements
for
all
disinfected
systems
to
be
operated
by
qualified
personnel
who
meet
the
requirements
specified
by
the
State,
which
may
differ
based
on
system
size
and
type.
The
rule
also
requires
that
States
maintain
a
register
of
qualified
operators
(
40
CFR
141.130(
c)).
While
the
Stage
2
DBPR
requirements
do
not
supercede
or
modify
the
requirement
that
disinfected
systems
be
operated
by
qualified
operators,
such
personnel
play
an
important
role
in
delivering
drinking
water
that
meets
Stage
2
MCLs
to
the
public.
States
should
also
review
and
modify,
as
required,
their
qualification
standards
to
take
into
account
new
technologies
(
e.
g.,
ultraviolet
(
UV)
disinfection)
and
new
compliance
requirements
(
including
159
simultaneous
compliance
and
consecutive
system
requirements).
EPA
received
only
one
comment
on
this
topic;
the
commenter
supported
the
need
for
a
qualified
operator.

M.
System
Reporting
and
Recordkeeping
Requirements
1.
Today's
rule
Today's
Stage
2
DBPR,
consistent
with
the
existing
system
reporting
and
recordkeeping
regulations
under
40
CFR
141.1314
(
Stage
1
DBPR),
requires
public
water
systems
(
including
consecutive
systems)
to
report
monitoring
data
to
States
within
ten
days
after
the
end
of
the
compliance
period.
In
addition,
systems
are
required
to
submit
the
data
required
in
§
141.134.

These
data
are
required
to
be
submitted
quarterly
for
any
monitoring
conducted
quarterly
or
more
frequently,
and
within
ten
days
of
the
end
of
the
monitoring
period
for
less
frequent
monitoring.

As
with
other
chemical
analysis
data,
the
system
must
keep
the
results
for
10
years.

In
addition
to
the
existing
Stage
1
reporting
requirements,
today's
rule
requires
systems
to
perform
specific
IDSE­
related
reporting
to
the
primacy
agency,
except
for
systems
serving
fewer
than
500
for
which
the
State
or
primacy
agency
has
waived
this
requirement.
Required
reporting
includes
submission
of
IDSE
monitoring
plans,
40/
30
certification,
and
IDSE
reports.
This
reporting
must
be
accomplished
on
the
schedule
specified
in
the
rule
(
see
§
141.600(
c))
and
discussed
in
section
IV.
E
of
today's
preamble.
System
submissions
must
include
the
elements
identified
in
subpart
U
and
discussed
further
in
section
IV.
F
of
today's
preamble.
These
elements
include
recommended
Stage
2
compliance
monitoring
sites
as
part
of
the
IDSE
report.

Systems
must
report
compliance
with
Stage
2
TTHM
and
HAA5
MCLs
(
0.080
mg/
L
TTHM
and
0.060
mg/
L
HAA5,
as
LRAAs)
according
to
the
schedules
specified
in
§
§
141.620
and
141.629
and
discussed
in
section
IV.
E
of
today's
preamble.
Reporting
for
DBP
monitoring,
as
described
previously,
will
remain
generally
consistent
with
current
public
water
system
reporting
160
requirements
(
§
141.31
and
§
141.134);
systems
will
be
required
to
calculate
and
report
each
LRAA
(
instead
of
the
system's
RAA)
and
each
individual
monitoring
result
(
as
required
under
the
Stage
1
DBPR).
Systems
will
also
be
required
to
provide
a
report
to
the
State
about
each
operational
evaluation
within
90
days,
as
discussed
in
section
IV.
H.
Reports
and
evaluations
must
be
kept
for
10
years
and
may
prove
valuable
in
identifying
trends
and
recurring
issues.

2.
Summary
of
major
comments
EPA
requested
comment
on
all
system
reporting
and
recordkeeping
requirements.

Commenters
generally
supported
EPA's
proposed
requirements,
but
expressed
concern
about
two
specific
issues.
The
first
issue
was
the
data
management
and
tracking
difficulties
that
States
would
face
if
EPA
finalized
a
monitoring
approach
which
had
both
plant­
based
and
populationbased
requirements,
as
was
proposed.
Since
today's
rule
contains
only
population­
based
monitoring
requirements,
this
concern
is
no
longer
an
issue.
See
section
IV.
G
in
today's
preamble
for
further
discussion.

The
second
concern
related
to
reporting
associated
with
the
IDSE.
Commenters
who
supported
an
approach
other
than
the
IDSE
for
determining
Stage
2
compliance
monitoring
locations
did
not
support
IDSE­
related
reporting.
The
IDSE
remains
a
key
component
of
the
final
rule;
thus,
EPA
has
retained
IDSE­
related
reporting.
However,
the
Agency
has
modified
both
the
content
and
the
timing
of
the
reporting
to
reduce
the
burden.
See
sections
IV.
F
and
IV.
E,
respectively,
of
today's
preamble
for
further
discussion.

N.
Approval
of
Additional
Analytical
Methods
1.
Today's
Rule
There
are
no
analytical
method
approvals
included
in
today's
action.
EPA
is
taking
final
action
to:
161
(
1)
allow
the
use
of
13
methods
published
by
the
Standard
Methods
Committee
in
Standard
Methods
for
the
Examination
of
Water
and
Wastewater,
20th
edition,
1998
(
APHA
1998)
and
12
methods
in
Standard
Methods
Online.

(
2)
approve
three
methods
published
by
American
Society
for
Testing
and
Materials
International.

(
3)
approve
EPA
Method
327.0
Revision
1.1
(
USEPA
2005h)
for
daily
monitoring
of
chlorine
dioxide
and
chlorite,
EPA
Method
552.3
(
USEPA
2003f)
for
haloacetic
acids
(
five)

(
HAA5),
EPA
Methods
317.0
Revision
2
(
USEPA
2001c)
and
326.0
(
USEPA
2002)
for
bromate,

chlorite,
and
bromide,
EPA
Method
321.8
(
USEPA
2000g)
for
bromate
only,
and
EPA
Method
415.3
Revision
1.1
(
USEPA
2005l)
for
total
organic
carbon
(
TOC)
and
specific
ultraviolet
absorbance
(
SUVA).

(
4)
update
the
citation
for
EPA
Method
300.1
(
USEPA
2000h)
for
bromate,
chlorite,
and
bromide.

(
5)
standardize
the
HAA5
sample
holding
times
and
the
bromate
sample
preservation
procedure
and
holding
time.

(
6)
add
the
requirement
to
remove
inorganic
carbon
prior
to
determining
TOC
or
DOC,

remove
the
specification
of
type
of
acid
used
for
TOC/
DOC
sample
preservation;
and
require
that
TOC
samples
be
preserved
at
the
time
of
collection.

(
7)
clarify
which
methods
are
approved
for
magnesium
hardness
determinations
(
40
CFR
141.131
and
141.135).

2.
Background
and
Analysis
The
Stage
1
Disinfectants
and
Disinfection
Byproducts
Rule
(
Stage
1
DBPR)
was
promulgated
on
December
16,
1998
(
USEPA
1998a)
and
it
included
approved
analytical
methods
for
DBPs,
disinfectants,
and
DBP
precursors.
Additional
analytical
methods
became
available
162
subsequent
to
the
rule
and
were
proposed
in
the
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
(
Stage
2
DBPR)
(
USEPA
2003a).
These
methods
are
applicable
to
monitoring
that
is
required
under
the
Stage
1
DBPR
and
are
not
tied
to
new
monitoring
requirements
proposed
in
the
Stage
2
DBPR.
After
the
Stage
2
DBPR
proposal,
analytical
methods
for
additional
drinking
water
contaminants
were
proposed
for
approval
in
a
mMethods
uUpdate
rRule
proposal
(
69
FR
18166,
April
6,
2004)
(
USEPA
2004).
The
Stage
2
DBPR
and
mMethods
uUpdate
rRule
proposals
both
included
changes
in
the
same
sections
of
the
CFR.
Thus,
EPA
decided
to
make
all
the
changes
at
one
time
rather
than
separating
them
in
different
rules.
Since
today's
action
was
preceded
by
EPA
action
on
the
methods
update
rule
(
USEPA
2005h),
EPA
approved
the
methods
includedto
§
141.131
as
part
of
the
Stage
2
DBPR
and
the
remainder
of
the
methods
that
were
proposed
with
the
Stage
2
DBPR
will
be
considered
as
part
of
the
Methods
Update
Rule,
which
will
be
finalized
at
a
later
date.
Two
ASTM
methods,
D
1253­
86(
96)
and
D
1253­
03,
that
were
proposed
in
the
Methods
Update
Rule,
are
being
approved
for
measuring
chlorine
residual
as
part
of
today's
action.

Minor
corrections
have
been
made
in
two
of
the
methods
that
were
proposed
in
the
Stage
2
DBPR
proposal
as
part
of
that
rule.
.
In
today's
rule,
the
Agency
is
approving
EPA
Method
327.0
(
Revision
1.1,
2005)
which
corrects
three
typographical
errors
in
the
proposed
method.

EPA
is
also
approving
EPA
Method
415.3
(
Revision
1.1,
2005),
which
does
not
contain
the
requirement
that
samples
for
the
analysis
of
TOC
must
be
received
within
48
hours
of
sample
collection.

A
summary
of
the
methods
that
are
included
in
today's
rule
is
presented
in
Table
IV.
N­
1.
163
Table
IV.
N­
1.
Analytical
Methods
Approved
in
Today's
Rule.

Analyte
EPA
Method
Standard
Methods
20th
Edition
Standard
Methods
Online
Other
§
141.131
­
Disinfection
Byproducts
HAA5
552.3
6251
B
6251
B­
94
Bromate
317.0,
Revision
2.0
321.8
326.0
ASTM
D
6581­
00
Chlorite
(
monthly
or
daily)
317.0,
Revision
2.0
326.0
ASTM
D
6581­
00
Chlorite
(
daily)
327.0,
Revision
1.1
4500­
ClO2
E
4500­
ClO2
E­
00
§
141.131
­
Disinfectants
Chlorine
(
free,
combined,
total)
4500­
Cl
D
4500­
Cl
F
4500­
Cl
G
4500­
Cl
D­
00
4500­
Cl
F­
00
4500­
Cl
G­
00
ASTM
D
1253­
86(
96)
ASTM
D
1253­
03
Chlorine
(
total)
4500­
Cl
E
4500­
Cl
I
4500­
Cl
E­
00
4500­
Cl
I­
00
Chlorine
(
free)
4500­
Cl
H
4500­
Cl
H­
00
Chlorine
Dioxide
327.0,
Revision
1.1
4500­
ClO2
D
4500­
ClO2
E
4500­
ClO2
E­
00
§
141.131
­
Other
parameters
Bromide
317.0,
Revision
2.0
326.0
ASTM
D
6581­
00
TOC/
DOC
415.3,
Revision
1.1
5310
B
5310
C
5310
D
5310
B­
00
5310
C­
00
5310
D­
00
UV254
415.3,
Revision
1.1
5910
B
5910
B­
00
SUVA
415.3,
Revision
1.1
164
O.
Laboratory
Certification
and
Approval
1.
PE
acceptance
criteria
a.
Today's
rule.
Today's
rule
maintains
the
requirements
of
laboratory
certification
for
laboratories
performing
analyses
to
demonstrate
compliance
with
MCLs
and
all
other
analyses
to
be
conducted
by
approved
parties.
It
revises
the
acceptance
criteria
for
performance
evaluation
(
PE)
studies
which
laboratories
must
pass
as
part
of
the
certification
program.
The
new
acceptance
limits
are
effective
60
days
after
promulgation.
Laboratories
that
were
certified
under
the
Stage
1
DBPR
PE
acceptance
criteria
will
be
subject
to
the
new
criteria
when
it
is
time
for
them
to
analyze
their
annual
DBP
PE
samples(
s).
Today's
rule
also
requires
that
TTHM
and
HAA5
analyses
that
are
performed
for
the
IDSE
or
system­
specific
study
be
conducted
by
laboratories
certified
for
those
analyses.
165
Table
IV.
O­
1.
Performance
Evaluation
(
PE)
Acceptance
Criteria
.

DBP
Acceptance
Limits
(
percent
of
true
value)
Comments
TTHM
Chloroform
Bromodichloromethane
Dibromochloromethane
Bromoform
±
20
±
20
±
20
±
20
Laboratory
must
meet
all
4
individual
THM
acceptance
limits
in
order
to
successfully
pass
a
PE
sample
for
TTHM
HAA5
Monochloroacetic
Acid
Dichloroacetic
Acid
Trichloroacetic
Acid
Monobromoacetic
Acid
Dibromoacetic
Acid
±
40
±
40
±
40
±
40
±
40
Laboratory
must
meet
the
acceptance
limits
for
4
out
of
5
of
the
HAA5
compounds
in
order
to
successfully
pass
a
PE
sample
for
HAA5
Chlorite
±
30
Bromate
±
30
b.
Background
and
analysis.
The
Stage
1
DBPR
(
USEPA
1998a)
specified
that
in
order
to
be
certified
the
laboratory
must
pass
an
annual
performance
evaluation
(
PE)
sample
approved
by
EPA
or
the
State
using
each
method
for
which
the
laboratory
wishes
to
maintain
certification.

The
acceptance
criteria
for
the
DBP
PE
samples
were
set
as
statistical
limits
based
on
the
performance
of
the
laboratories
in
each
study.
This
was
done
because
EPA
did
not
have
enough
data
to
specify
fixed
acceptance
limits.

Subsequent
to
promulgation
of
the
Stage
1
DBPR,
EPA
was
able
to
evaluate
data
from
PE
studies
conducted
during
the
Information
Collection
Rule
(
USEPA
1996)
and
during
the
last
five
general
Water
Supply
PE
studies.
Based
on
the
evaluation
process
as
described
in
the
proposed
Stage
2
DBPR
(
USEPA
2003a),
EPA
determined
that
fixed
acceptance
limits
could
be
established
for
the
DBPs.
Today's
action
replaces
the
statistical
PE
acceptance
limits
with
fixed
limits
effective
one
year
after
promulgation.

c.
Summary
of
major
comments.
Four
commenters
supported
the
fixed
acceptance
criteria
as
presented
in
the
proposed
rule.
One
requested
that
a
minimum
concentration
be
set
for
166
each
DBP
in
the
PE
studies,
so
that
laboratories
would
not
be
required
to
meet
tighter
criteria
in
the
PE
study
than
they
are
required
to
meet
with
the
minimum
reporting
level
(
MRL)
check
standard.
EPA
has
addressed
this
concern
by
directing
the
PE
sample
suppliers
to
use
concentrations
no
less
than
10
µ
g/
L
for
the
individual
THM
and
HAAs,
100
µ
g/
L
for
chlorite,
and
7
µ
g/
L
for
bromate
in
PE
studies
used
for
certifying
drinking
water
laboratories.

Two
commenters
requested
that
the
effective
date
for
the
new
PE
acceptance
criteria
be
extended
from
60
days
to
180
days,
because
they
felt
that
60
days
was
not
enough
time
for
laboratories
to
meet
the
new
criteria.
EPA
realized
from
those
comments
that
the
original
intent
of
the
proposal
was
not
clearly
explained;
the
60
days
was
to
be
the
deadline
for
when
the
PE
providers
must
change
the
acceptance
criteria
that
are
used
when
the
studies
are
conducted.

Laboratories
would
have
to
meet
the
criteria
when
it
is
time
for
them
to
analyze
their
annual
PE
samples
in
order
to
maintain
certification.
Depending
upon
when
the
last
PE
sample
was
analyzed,
laboratories
could
have
up
to
one
year
to
meet
the
new
criteria.
In
order
to
eliminate
this
confusion,
EPA
has
modified
the
rule
language
to
allow
laboratories
one
year
from
today's
date
to
meet
the
new
PE
criteria.

2.
Minimum
reporting
limits
a.
Today's
rule.
EPA
is
establishing
regulatory
minimum
reporting
limits
(
MRLs)
for
compliance
reporting
of
DBPs
by
Public
Water
Systems.
These
regulatory
MRLs
(
Table
IV.
O­
2)

also
define
the
minimum
concentrations
that
must
be
reported
as
part
of
the
Consumer
Confidence
Reports
(
40
CFR
§
141.151(
d)).
EPA
is
incorporating
MRLs
into
the
laboratory
certification
program
for
DBPs
by
requiring
laboratories
to
include
a
standard
near
the
MRL
concentration
as
part
of
the
calibration
curve
for
each
DBP
and
to
verify
the
accuracy
of
the
calibration
curve
at
the
MRL
concentration
by
analyzing
an
MRL
check
standard
with
a
concentration
less
than
or
equal
to
110%
of
the
MRL
with
each
batch
of
samples.
The
measured
167
DBP
concentration
for
the
MRL
check
standard
must
be
±
50%
of
the
expected
value,
if
any
field
sample
in
the
batch
has
a
concentration
less
than
5
times
the
regulatory
MRL.

Table
IV.
O­
2.
Regulatory
Minimum
Reporting
Levels
DBP
Minimum
reporting
level
(
mg/
L)
1
Comments
TTHM
2
Chloroform
Bromodichloromethane
Dibromochloromethane
Bromoform
0.0010
0.0010
0.0010
0.0010
HAA5
2
Monochloroacetic
Acid
Dichloroacetic
Acid
Trichloroacetic
Acid
Monobromoacetic
Acid
Dibromoacetic
Acid
0.0020
0.0010
0.0010
0.0010
0.0010
Chlorite
0.020
Applicable
to
monitoring
as
prescribed
in
§
141.132(
b)(
2)(
i)(
B)
and
(
b)(
2)(
ii).

Bromate
0.0050
or
0.0010
Laboratories
that
use
EPA
Methods
317.0
Revision
2.0,
326.0
or
321.8
must
meet
a
0.0010
mg/
L
MRL
for
bromate.

1
The
calibration
curve
must
encompass
the
regulatory
minimum
reporting
level
(
MRL)
concentration.
Data
may
be
reported
for
concentrations
lower
than
the
regulatory
MRL
as
long
as
the
precision
and
accuracy
criteria
are
met
by
analyzing
an
MRL
check
standard
at
the
lowest
reporting
limit
chosen
by
the
laboratory.
The
laboratory
must
verify
the
accuracy
of
the
calibration
curve
at
the
MRL
concentration
by
analyzing
an
MRL
check
standard
with
a
concentration
less
than
or
equal
to
110%
of
the
MRL
with
each
batch
of
samples.
The
measured
concentration
for
the
MRL
check
standard
must
be
±
50%
of
the
expected
value,
if
any
field
sample
in
the
batch
has
a
concentration
less
than
5
times
the
regulatory
MRL.
Method
requirements
to
analyze
higher
concentration
check
standards
and
meet
tighter
acceptance
criteria
for
them
must
be
met
in
addition
to
the
MRL
check
standard
requirement.
2
When
adding
the
individual
trihalomethane
or
haloacetic
acid
concentrations
to
calculate
the
TTHM
or
HAA5
concentrations,
respectively,
a
zero
is
used
for
any
analytical
result
that
is
less
than
the
MRL
concentration
for
that
DBP,
unless
otherwise
specified
by
the
State.

b.
Background
and
analysis.
EPA
proposed
to
establish
regulatory
MRLs
for
DBPs
in
order
to
define
expectations
for
reporting
compliance
monitoring
data
to
the
Primacy
Agencies
168
and
in
the
Consumer
Confidence
Reports.
The
proposed
MRLs
were
generally
based
on
those
used
during
the
Information
Collection
Rule
(
USEPA
1996),
because
an
analysis
of
the
quality
control
data
set
from
the
Information
Collection
Rule
(
Fair
et
al.
2002)
indicated
that
laboratories
are
able
to
provide
quantitative
data
down
to
those
concentrations.

EPA
also
proposed
that
laboratories
be
required
to
demonstrate
ability
to
quantitate
at
the
MRL
concentrations
by
analyzing
an
MRL
check
standard
and
meeting
accuracy
criteria
on
each
day
that
compliance
samples
are
analyzed.
Three
public
commenters
noted
that
meeting
the
accuracy
requirement
for
the
MRL
check
standard
did
not
contribute
to
the
quality
of
the
data
in
cases
in
which
the
concentration
of
a
DBP
in
the
samples
was
much
higher
than
the
MRL.
For
example,
if
chloroform
concentrations
are
always
greater
than
0.040
mg/
L
in
a
water
system's
samples,
then
verifying
accurate
quantitation
at
0.0010
mg/
L
is
unnecessary
and
may
require
the
laboratory
to
dilute
samples
or
maintain
two
calibration
curves
in
order
to
comply
with
the
requirement.
EPA
has
taken
this
into
consideration
in
today's
rule
and
has
adjusted
the
requirement
accordingly.
EPA
is
maintaining
the
requirement
for
all
laboratories
to
analyze
the
MRL
check
standard,
but
the
laboratory
is
only
required
to
meet
the
accuracy
criteria
(
±
50%)
if
a
field
sample
has
a
concentration
less
than
five
times
the
regulatory
MRL
concentration.

EPA
proposed
a
regulatory
MRL
of
0.200
mg/
L
for
chlorite,
because
data
from
the
Information
Collection
Rule
indicated
that
most
samples
would
contain
concentrations
greater
than
0.200
mg/
L
(
USEPA
2003c).
EPA
also
took
comment
on
a
lower
MRL
of
0.020
mg/
L.

Commenters
were
evenly
divided
concerning
which
regulatory
MRL
concentration
should
be
adopted
in
the
final
rule.
EPA
has
decided
to
set
the
chlorite
regulatory
MRL
at
0.020
mg/
L
in
today's
rule.
This
decision
was
based
on
two
factors.
First,
the
approved
analytical
methods
for
determining
compliance
with
the
chlorite
MCL
can
easily
support
an
MRL
of
0.020
mg/
L.
More
importantly,
since
the
proposal,
EPA
has
learned
that
water
systems
that
have
low
chlorite
169
concentrations
in
their
water
have
been
obtaining
data
on
these
low
concentrations
from
their
laboratories
and
have
been
using
these
data
in
their
Consumer
Confidence
Reports.
Setting
the
MRL
at
0.020
mg/
L
is
reflective
of
current
practices
in
laboratories
and
current
data
expectations
by
water
systems.

c.
Summary
of
major
comments.
There
were
no
major
comments.

P.
Other
regulatory
changes
As
part
of
today's
action,
EPA
has
included
several
"
housekeeping"
actions
to
remove
sections
of
Part
141
that
are
no
longer
effective.
These
sections
have
been
superceded
by
new
requirements
elsewhere
in
Part
141.

Sections
141.12
(
Maximum
contaminant
levels
for
total
trihalomethanes)
and
141.30
(
Total
trihalomethanes
sampling,
analytical
and
other
requirements)
were
promulgated
as
part
of
the
1979
TTHM
Rule.
These
sections
have
been
superceded
in
their
entirety
by
§
141.64
(
Maximum
contaminant
levels
for
disinfection
byproducts)
and
subpart
L
(
Disinfectant
Residuals,

Disinfection
Byproducts,
and
Disinfection
Byproduct
Precursors),
respectively,
as
of
December
31,
2003.
Also,
§
141.32
(
Public
notification)
has
been
superceded
by
subpart
Q
(
Public
Notification
of
Drinking
Water
Violations),
which
is
now
fully
in
effect.

Section
553
of
the
Administrative
Procedure
Act,
5
U.
S.
C.
553(
b)(
B),
provides
that,

when
an
agency
for
good
cause
finds
that
notice
and
public
procedure
are
impracticable,

unnecessary,
or
contrary
to
the
public
interest,
the
agency
may
issue
a
rule
without
providing
prior
notice
and
an
opportunity
for
public
comment.
In
addition
to
updating
methods,
this
rule
also
makes
minor
corrections
to
the
National
Primary
Drinking
Water
Regulations,
specifically
the
Public
Notification
tables
(
Subpart
Q,
Appendices
A
and
B).
Two
final
drinking
water
rules
(
66
FR
6976
and
65
FR
76708)
inadvertently
added
new
endnotes
to
two
existing
tables
using
the
170
same
endnote
numbers.
This
rule
corrects
this
technical
drafting
error
by
renumbering
the
endnote
citations
in
these
two
tables.
Thus,
additional
notice
and
public
comment
is
not
necessary.
EPA
finds
that
this
constitutes
"
good
cause"
under
5
U.
S.
C.
553(
b)(
B).
For
the
same
reasons,
EPA
is
making
this
rule
change
effective
upon
publication.
5
U.
S.
C.
553(
d)(
3).

V.
State
Implementation
A.
Today's
rule
This
section
describes
the
regulations
and
other
procedures
and
policies
States
must
adopt
to
implement
today's
rule.
States
must
continue
to
meet
all
other
conditions
of
primacy
in
40
CFR
Part
142.
To
implement
the
Stage
2
DBPR,
States
must
adopt
revisions
to
the
following:

­
§
141.2
­
Definitions
­
§
141.33
­
Record
maintenance;

­
§
141.64
­
Maximum
contaminant
levels
for
disinfection
byproducts;

­
subpart
L
­
Disinfectant
Residuals,
Disinfection
Byproducts,
and
Disinfection
Byproduct
Precursors;

­
subpart
O,
Consumer
Confidence
Reports;

­
subpart
Q,
Public
Notification
of
Drinking
Water
Violations;

­
new
subpart
U,
Initial
Distribution
System
Evaluation;
and
­
new
subpart
V,
Stage
2
Disinfection
Byproducts
Requirements.

1.
State
Primacy
Requirements
for
Implementation
Flexibility
In
addition
to
adopting
basic
primacy
requirements
specified
in
40
CFR
Part
142,
States
are
required
to
address
applicable
special
primacy
conditions.
Special
primacy
conditions
pertain
to
specific
regulations
where
implementation
of
the
rule
involves
activities
beyond
general
primacy
provisions.
The
purpose
of
these
special
primacy
requirements
in
today's
rule
is
to
171
ensure
State
flexibility
in
implementing
a
regulation
that
(
1)
applies
to
specific
system
configurations
within
the
particular
State
and
(
2)
can
be
integrated
with
a
State's
existing
Public
Water
Supply
Supervision
Program.
States
must
include
these
rule­
distinct
provisions
in
an
application
for
approval
or
revision
of
their
program.
These
primacy
requirements
for
implementation
flexibility
are
discussed
in
this
section.

To
ensure
that
a
State
program
includes
all
the
elements
necessary
for
an
effective
and
enforceable
program
under
today's
rule,
a
State
primacy
application
must
include
a
description
of
how
the
State
will
implement
a
procedure
for
modifying
consecutive
system
and
wholesale
system
monitoring
requirements
on
a
case­
by­
case
basis,
if
a
State
will
use
the
authority
to
modify
monitoring
requirements
under
this
special
primacy
condition.

2.
State
recordkeeping
requirements
Today's
rule
requires
States
to
keep
additional
records
of
the
following,
including
all
supporting
information
and
an
explanation
of
the
technical
basis
for
each
decision:

­
very
small
system
waivers.

­
IDSE
monitoring
plans.

­
IDSE
reports
and
40/
30
certifications,
plus
any
modifications
required
by
the
State.

­
operational
evaluations
conducted
by
the
system.

3.
State
reporting
requirements
Today's
rule
has
no
new
State
reporting
requirements.

4.
Interim
primacy
States
that
have
primacy
for
every
existing
NPDWR
already
in
effect
may
obtain
interim
primacy
for
this
rule,
beginning
on
the
date
that
the
State
submits
the
application
for
this
rule
to
USEPA,
or
the
effective
date
of
its
revised
regulations,
whichever
is
later.
A
State
that
wishes
to
obtain
interim
primacy
for
future
NPDWRs
must
obtain
primacy
for
today's
rule.
As
described
in
172
Section
IV.
F,
EPA
expects
to
work
with
States
to
oversee
the
individual
distribution
system
evaluation
process
that
begins
shortly
after
rule
promulgation.

5.
IDSE
implementation
As
discussed
in
section
IV.
E,
many
systems
will
be
performing
certain
IDSE
activities
prior
to
their
State
receiving
primacy.
During
that
period,
EPA
will
act
as
the
primacy
agency,

but
will
consult
and
coordinate
with
individual
States
to
the
extent
practicable
and
to
the
extent
that
States
are
willing
and
able
to
do
so.
In
addition,
prior
to
primacy,
States
may
be
asked
to
assist
EPA
in
identifying
and
confirming
systems
that
are
required
to
comply
with
certain
IDSE
activities.
Once
the
State
has
received
primacy,
it
will
become
responsible
for
IDSE
implementation
activities.

B.
Background
and
Analysis
SDWA
establishes
requirements
that
a
State
or
eligible
Indian
Tribe
must
meet
to
assume
and
maintain
primary
enforcement
responsibility
(
primacy)
for
its
PWSs.
These
requirements
include
the
following
activities:
1)
adopting
drinking
water
regulations
that
are
no
less
stringent
than
Federal
drinking
water
regulations;
2)
adopting
and
implementing
adequate
procedures
for
enforcement;
3)
keeping
records
and
making
reports
available
on
activities
that
EPA
requires
by
regulation;
4)
issuing
variances
and
exemptions
(
if
allowed
by
the
State),
under
conditions
no
less
stringent
than
allowed
under
SDWA;
and
5)
adopting
and
being
capable
of
implementing
an
adequate
plan
for
the
provisions
of
safe
drinking
water
under
emergency
situations.

40
CFR
part
142
sets
out
the
specific
program
implementation
requirements
for
States
to
obtain
primacy
for
the
public
water
supply
supervision
program
as
authorized
under
SDWA
section
1413.
In
addition
to
adopting
basic
primacy
requirements
specified
in
40
CFR
Part
142,

States
may
be
required
to
adopt
special
primacy
provisions
pertaining
to
specific
regulations
where
implementation
of
the
rule
involves
activities
beyond
general
primacy
provisions.
States
173
must
include
these
regulation
specific
provisions
in
an
application
for
approval
of
their
program
revision.

The
current
regulations
in
40
CFR
142.14
require
States
with
primacy
to
keep
various
records,
including
the
following:
analytical
results
to
determine
compliance
with
MCLs,
MRDLs,

and
treatment
technique
requirements;
PWS
inventories;
State
approvals;
enforcement
actions;

and
the
issuance
of
variances
and
exemptions.
Today's
final
rule
requires
States
to
keep
additional
records,
including
all
supporting
information
and
an
explanation
of
the
technical
basis
for
decisions
made
by
the
State
regarding
today'
rule
requirements.
The
State
may
use
these
records
to
identify
trends
and
determine
whether
to
limit
the
scope
of
operational
evaluations.

EPA
currently
requires
in
40
CFR
142.15
that
States
report
to
EPA
information
such
as
violations,
variance
and
exemption
status,
and
enforcement
actions;
today's
rule
does
not
add
additional
reporting
requirements
or
modify
existing
requirements.

On
April
28,
1998,
EPA
amended
its
State
primacy
regulations
at
40
CFR
142.12
to
incorporate
the
new
process
identified
in
the
1996
SDWA
Amendments
for
granting
primary
enforcement
authority
to
States
while
their
applications
to
modify
their
primacy
programs
are
under
review
(
63
FR
23362,
April
28,
1998)
(
USEPA
1998cf).
The
new
process
grants
interim
primary
enforcement
authority
for
a
new
or
revised
regulation
during
the
period
in
which
EPA
is
making
a
determination
with
regard
to
primacy
for
that
new
or
revised
regulation.
This
interim
enforcement
authority
begins
on
the
date
of
the
primacy
application
submission
or
the
effective
date
of
the
new
or
revised
State
regulation,
whichever
is
later,
and
ends
when
EPA
makes
a
final
determination.
However,
this
interim
primacy
authority
is
only
available
to
a
State
that
has
primacy
(
including
interim
primacy)
for
every
existing
NPDWR
in
effect
when
the
new
regulation
is
promulgated.
States
that
have
primacy
for
every
existing
NPDWR
already
in
effect
may
obtain
interim
primacy
for
this
rule
and
a
State
that
wishes
to
obtain
interim
primacy
for
future
NPDWRs
174
must
obtain
primacy
for
this
rule.

EPA
is
aware
that
due
to
the
complicated
wholesale
system­
consecutive
system
relationships
that
exist
nationally,
there
will
be
cases
where
the
standard
monitoring
framework
will
be
difficult
to
implement.
Therefore,
States
may
develop,
as
a
special
primacy
condition,
a
program
under
which
the
State
can
modify
monitoring
requirements
for
consecutive
systems.

These
modifications
must
not
undermine
public
health
protection
and
all
systems,
including
consecutive
systems,
must
comply
with
the
TTHM
and
HAA5
MCLs
based
on
the
LRAA
at
each
compliance
monitoring
location.
Each
consecutive
system
must
have
at
least
one
compliance
monitoring
location.
However,
such
a
program
allows
the
State
to
establish
monitoring
requirements
that
account
for
complicated
distribution
system
relationships,
such
as
where
neighboring
systems
buy
from
and
sell
to
each
other
regularly
throughout
the
year,
water
passes
through
multiple
consecutive
systems
before
it
reaches
a
user,
or
a
large
group
of
interconnected
systems
have
a
complicated
combined
distribution
system.
EPA
has
developed
a
guidance
manual
to
address
these
and
other
consecutive
system
issues.

C.
Summary
of
Major
Comments
Public
comment
generally
supported
the
special
primacy
requirements
in
the
August
11,

2003
proposal,
and
many
commenters
expressed
appreciation
for
the
flexibility
the
special
primacy
requirements
provided
to
States.

Many
commenters
expressed
concern
about
EPA
as
the
implementer
instead
of
the
State,

given
the
existing
relationship
between
the
State
and
system.
EPA
agrees
that
States
perform
an
essential
role
in
rule
implementation
and
intends
to
work
with
States
to
the
greatest
extent
possible,
consistent
with
the
rule
schedule
promulgated
today.
EPA
believes
that
prepromulgation
coordination
with
States,
changes
in
the
final
rule
strongly
supported
by
States
175
(
e.
g.,
population­
based
monitoring
instead
of
plant­
based
monitoring),
and
the
staggered
rule
schedule
will
facilitate
State
involvement
in
pre­
primacy
implementation.

Many
commenters
also
requested
that
the
State
have
more
flexibility
to
grant
sampling
waivers
and
exemptions.
EPA
believes
that
it
has
struck
a
reasonable
balance
among
competing
objectives
in
granting
State
flexibility.
State
flexibility
comes
at
a
resource
cost
and
excessive
system­
by­
system
flexibility
could
overwhelm
State
resources.
Also,
EPA
believes
that
much
of
the
monitoring
and
water
quality
information
a
State
would
need
to
properly
consider
whether
a
waiver
is
appropriate
is
generally
not
available
and,
if
available,
difficult
to
evaluate.

VI.
Economic
Analysis
This
section
summarizes
the
Economic
Analysis
for
the
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
(
Economic
Analysis
(
EA)
for
the
Stage
2
DBPR)
(
USEPA
2005a).

The
EA
is
an
evaluation
of
the
benefits
and
costs
of
today's
final
rule
and
other
regulatory
alternatives
the
Agency
considered.
Specifically,
this
evaluation
addresses
both
quantified
and
non­
quantified
benefits
to
PWS
consumers,
including
the
general
population
and
sensitive
subpopulations.
Costs
are
presented
for
PWSs,
States,
and
consumer
households.
Also
included
is
a
discussion
of
potential
risks
from
other
contaminants,
uncertainties
in
benefit
and
cost
estimates,
and
a
summary
of
major
comments
on
the
EA
for
the
proposed
Stage
2
DBPR.

EPA
relied
on
data
from
several
epidemiologic
and
toxicologic
studies,
the
Information
Collection
Rule
(
ICR),
and
other
sources,
along
with
analytical
models
and
input
from
technical
experts,
to
understand
DBP
risk,
occurrence,
and
PWS
treatment
changes
that
will
result
from
today's
rule.
Benefits
and
costs
are
presented
as
annualized
values
using
social
discount
rates
of
three
and
seven
percent.
The
time
frame
used
for
benefit
and
cost
comparisons
is
25
years
­

approximately
five
years
account
for
rule
implementation
and
20
years
for
the
average
useful
life
176
of
treatment
technologies.

EPA
has
prepared
this
EA
to
comply
with
the
requirements
of
SDWA,
including
the
Health
Risk
Reduction
and
Cost
Analysis
required
by
SDWA
section
1412(
b)(
3)(
C),
and
Executive
Order
12866,
Regulatory
Planning
and
Review.
The
full
EA
is
available
in
the
docket
for
today's
rule,
which
is
available
ononline
as
described
in
the
Agency's
web
site:

http://
www.
epa.
gov/
edocket"
ADDRESSES"
section.
The
full
document
provides
detailed
explanations
of
the
analyses
summarized
in
this
section
and
additional
analytical
results.

A.
Regulatory
Alternatives
Considered
The
Stage
2
DBPR
is
the
second
in
a
set
of
rules
that
address
public
health
risks
from
DBPs.
EPA
promulgated
the
Stage
1
DBPR
to
decrease
average
exposure
to
DBPs
and
mitigate
associated
health
risks
­
compliance
with
TTHM
and
HAA5
MCLs
is
based
on
averaging
concentrations
across
the
distribution
system.
In
developing
the
Stage
2
DBPR,
EPA
sought
to
identify
and
further
reduce
remaining
risks
from
exposure
to
chlorinated
DBPs.

The
regulatory
options
EPA
considered
for
the
Stage
2
DBPR
are
the
direct
result
of
a
consensus
rulemaking
process
(
Federal
Advisory
Committee
Act
(
FACA)
process)
that
involved
various
drinking
water
stakeholders
(
see
Section
III
for
a
description
of
the
FACA
process).
The
Advisory
Committee
considered
the
following
key
questions
during
the
negotiation
process
for
the
Stage
2
DBPR:

C
What
are
the
remaining
health
risks
after
implementation
of
the
Stage
1
DBPR?

C
What
are
approaches
to
addressing
these
risks?

C
What
are
the
risk
tradeoffs
that
need
to
be
considered
in
evaluating
these
approaches?

C
How
do
the
estimated
costs
of
an
approach
compare
to
reductions
in
peak
DBP
occurrences
and
overall
DBP
exposure
for
that
approach?
177
The
Advisory
Committee
considered
DBP
occurrence
estimates
to
be
important
in
understanding
the
nature
of
public
health
risks.
Although
the
ICR
data
were
collected
prior
to
promulgation
of
the
Stage
1
DBPR,
they
were
collected
under
a
similar
sampling
strategy.
The
data
support
the
concept
that
a
system
could
be
in
compliance
with
the
RAA
Stage
1
DBPR
MCLs
of
0.080
mg/
L
and
0.060
mg/
L
for
TTHM
and
HAA5,
respectively,
and
yet
have
points
in
the
distribution
system
with
either
periodically
or
consistently
higher
DBP
levels.

Based
on
these
findings,
the
Advisory
Committee
discussed
an
array
of
alternatives
to
address
disproportionate
risk
within
distribution
systems.
Alternative
options
included
lowering
DBP
MCLs,
revising
the
method
for
MCL
compliance
determination
(
e.
g.,
requiring
individual
sampling
locations
to
meet
the
MCL
as
an
LRAA
or
requiring
that
no
samples
exceed
the
MCL),

and
combinations
of
both.
The
Advisory
Committee
also
considered
the
associated
technology
changes
and
costs
for
these
alternatives.
After
narrowing
down
options,
the
Advisory
Committee
primarily
focused
on
four
types
of
alternative
MCL
scenarios.
These
are
the
alternatives
EPA
evaluated
in
the
EA,
as
follows:

Preferred
Alternative
­
MCLs
of
0.080
mg/
L
for
TTHM
and
0.060
mg/
L
for
HAA5
as
LRAAs
­
Bromate
MCL
remaining
at
0.010
mg/
L
Alternative
1
­
MCLs
of
0.080
mg/
L
for
TTHM
and
0.060
mg/
L
for
HAA5
as
LRAAs
­
Bromate
MCL
of
0.005
mg/
L
Alternative
2
­
MCLs
of
0.080
mg/
L
for
TTHM
and
0.060
mg/
L
for
HAA5
as
absolute
maximums
for
individual
measurements
­
Bromate
MCL
remaining
at
0.010
mg/
L
178
Alternative
3
­
MCLs
of
0.040
mg/
L
for
TTHM
and
0.030
mg/
L
for
HAA5
as
RAAs
­
Bromate
MCL
remaining
at
0.010
mg/
L.

Figure
VI.
A­
1
shows
how
compliance
would
be
determined
under
each
of
the
TTHM/
HAA5
alternatives
described
and
the
Stage
1
DBPR
for
a
hypothetical
large
surface
water
system.
This
hypothetical
system
has
one
treatment
plant
and
measures
TTHM
in
the
distribution
system
in
four
locations
per
quarter
(
the
calculation
methodology
shown
would
be
the
same
for
HAA5).
Ultimately,
the
Advisory
Committee
recommended
the
Preferred
Alternative
in
combination
with
an
IDSE
requirement
(
discussed
in
Section
IV.
F).
179
Basis
of
Compliance
Violation
of
MCL
Stage
1
DBPR
TTHM
MCL
=
80
µ
g/
L
measured
as
an
RAA
No
exceedance
of
MCL
Loc.
1
Loc.
2
Loc.
3
Loc.
4
Qtrly
Avg.
Q1
100
40
50
50
60
Q2
75
50
40
100
66
Q3
55
45
55
110
66
Q4
60
55
40
75
58
RAA
63
Preferred
Stage
2
DBPR
Alternative
and
Alternative
11
TTHM
MCL
=
80
µ
g/
L
measured
as
an
LRAA
LRAA
at
Location
4
exceeds
MCL
Loc.
1
2
Loc.
2
2
Loc.
3
2
Loc.
4
2
Q1
100
40
50
50
Q2
75
50
40
100
Q3
55
45
55
110
Q4
60
55
40
75
LRAA
73
48
46
84
1
The
Preferred
Alternative
and
Alternative
1
have
the
same
TTHM
MCL;
they
differ
only
in
regard
to
the
bromate
MCL.
2
Based
on
the
IDSE,
new
locations
targeted
for
high
DBPs.

Alternative
2
TTHM
MCL
=
80
µ
g/
L
measured
as
a
single
highest
value
Three
samples
at
Locations
1
and
4
exceed
MCL
Loc.
1
Loc.
2
Loc.
3
Loc.
4
Q1
100
40
50
50
Q2
75
50
40
100
Q3
55
45
55
110
Q4
60
55
40
75
Alternative
3
TTHM
MCL
=
40
µ
g/
L
measured
as
an
RAA
RAA
exceeds
MCL
Loc.
1
Loc.
2
Loc.
3
Loc.
4
Qtrly
Avg.
Q1
100
40
50
50
60
Q2
75
50
40
100
66
Q3
55
45
55
110
66
Q4
60
55
40
75
58
RAA
63
Figure
VI.
A­
1.
Calculations
of
Compliance
for
the
Regulatory
Alternatives
Considered
180
B.
Analyses
that
Support
Today's
Final
Rule
EPA's
goals
in
designing
the
Stage
2
DBPR
were
to
protect
public
health
by
reducing
peak
DBP
levels
in
the
distribution
system
while
maintaining
microbial
protection.
As
described
earlier,
the
Stage
1
DBPR
reduces
overall
average
DBP
levels,
but
specific
locations
within
distribution
systems
can
still
experience
relatively
high
DBP
concentrations.
EPA
believes
that
high
DBP
concentrations
should
be
reduced
due
to
the
potential
association
of
DBPs
with
cancer,

as
well
as
reproductive
and
developmental
heath
effects.

EPA
analyzed
the
benefits
and
costs
of
the
four
regulatory
alternatives
presented
in
the
previous
section.
Consistent
with
the
recommendations
of
the
Advisory
Committee,
EPA
is
establishing
the
preferred
alternative
to
achieve
the
Agency's
goals
for
the
Stage
2
DBPR.
The
following
discussion
summarizes
EPA's
analyses
that
support
today's
final
rule.
This
discussion
explains
how
EPA
predicted
water
quality
and
treatment
changes,
estimated
benefits
and
costs,

and
assessed
the
regulatory
alternatives.

1.
Predicting
water
quality
and
treatment
changes
Water
quality
and
treatment
data
from
the
ICR
were
used
in
predicting
treatment
plant
technology
changes
(
i.
e.
compliance
forecasts)
and
reductions
in
DBP
exposure
resulting
from
the
Stage
2
DBPR.
Because
ICR
data
were
gathered
prior
to
Stage
1
DBPR
compliance
deadlines,

EPA
first
accounted
for
treatment
changes
resulting
from
the
Stage
1
DBPR.
Benefit
and
cost
estimates
for
the
Stage
2
DBPR
reflect
changes
following
compliance
with
the
Stage
1
DBPR.

The
primary
model
used
to
predict
changes
in
treatment
and
reductions
in
DBP
levels
was
the
Surface
Water
Analytical
Tool
(
SWAT),
which
EPA
developed
using
results
from
the
ICR.

SWAT
results
were
applied
directly
for
large
and
medium
surface
water
systems
and
were
adjusted
for
small
surface
water
systems
to
account
for
differences
in
source
water
DBP
precursor
levels
and
operational
constraints
in
small
systems.
EPA
used
ICR
data
and
a
Delphi
181
poll
process
(
a
group
of
drinking
water
experts
who
provided
best
professional
judgment
in
a
structured
format)
to
project
technologies
selected
by
ground
water
systems.

To
address
uncertainty
in
SWAT
predictions,
EPA
also
predicted
treatment
changes
using
a
second
methodology,
called
the
"
ICR
Matrix
Method."
Rather
than
a
SWAT­
predicted
pre­

Stage
1
baseline,
the
ICR
Matrix
Method
uses
unadjusted
ICR
TTHM
and
HAA5
pre­
Stage
1
data
to
estimate
the
percent
of
plants
changing
technology
to
comply
with
the
Stage
2
DBPR.

EPA
gives
equal
weight
to
SWAT
and
ICR
Matrix
Method
predictions
in
estimating
Stage
2
compliance
forecasts
and
resultant
reductions
in
DBP
exposure.
The
ICR
Matrix
Method
is
also
used
to
estimate
reductions
in
the
occurrence
of
peak
TTHM
and
HAA5
concentrations
because
SWAT­
predicted
TTHM
and
HAA5
concentrations
are
valid
only
when
considering
national
averages,
not
at
the
plant
level.

When
evaluating
compliance
with
a
DBP
MCL,
EPA
assumed
that
systems
would
maintain
DBP
levels
at
least
20
percent
below
the
MCL.
This
safety
margin
represents
the
level
at
which
systems
typically
take
action
to
ensure
they
meet
a
drinking
water
standard
and
reflects
industry
practice.
In
addition,
the
safety
margin
accounts
for
year­
to­
year
fluctuations
in
DBP
levels.
To
address
the
impact
of
the
IDSE,
EPA
also
analyzed
compliance
using
a
safety
margin
of
25
percent
based
on
an
analysis
of
spatial
variability
in
TTHM
and
HAA5
occurrence.
EPA
assigned
equal
probability
to
the
20
and
25
percent
safety
margin
for
large
and
medium
surface
water
systems
for
the
final
analysis
because
both
alternatives
are
considered
equally
plausible.

EPA
assumes
the
20
percent
operational
safety
margin
accounts
for
variability
in
small
surface
water
systems
and
all
groundwater
systems.

2.
Estimating
benefits
Quantified
benefits
estimates
for
the
Stage
2
DBPR
are
based
on
potential
reductions
in
fatal
and
non­
fatal
bladder
cancer
cases.
In
the
EA,
EPA
included
a
sensitivity
analysis
for
182
benefits
from
avoiding
colon
and
rectal
cancers.
An
illustrative
example
of
reduction
in
one
potential
reproductive
and
developmental
health
endpoint
(
fetal
loss)
is
also
presented
because
EPA
predicts
that
a
significant
portion
of
the
totalEPA
believes
additional
benefits
from
this
rule
could
come
from
reduction
in
developmental
and
reproductive
health
effects,
although
the
science
on
these
effects
as
a
result
of
DBP
exposure
is
not
strong
enough
to
fully
quantify
risk
or
benefits.

reducing
potential
reproductive
and
developmental
risks.
EPA
has
not
included
these
potential
risks
in
the
primary
benefit
analysis
because
of
the
associated
uncertainty.

The
major
steps
in
deriving
and
characterizing
bothpotential
cancer
and
fetal
loss
cases
avoided
include
the
following:
(
1)
estimate
the
current
and
future
annual
cases
of
illness
from
all
causes;
(
2)
estimate
how
many
cases
can
be
attributed
to
DBP
occurrence
and
exposure;
and
(
3)

estimate
the
reduction
in
future
cases
corresponding
to
anticipated
reductions
in
DBP
occurrence
and
exposure
due
to
the
Stage
2
DBPR.

EPA
used
results
from
the
National
Cancer
Institute's
Surveillance,
Epidemiology,
and
End
Results
(
SEER,
2004)
program
in
conjunction
with
data
from
the
2000
U.
S.
Census
to
estimate
the
number
of
new
bladder
cancer
cases
per
year
(
USEPA
2005a).
Three
approaches
were
then
used
to
gauge
the
percentage
of
cases
attributable
to
DBP
exposure
(
i.
e.,
population
attributable
risk
(
PAR)).
AllTaken
together,
the
three
approaches
are
equally
valid
and
give
feasible
estimates
of
riskprovide
a
reasonable
estimate
of
the
range
of
potential
risks.
EPA
notes
that
the
existing
epidemiological
evidence
has
not
conclusively
established
causality
between
DBP
exposure
and
any
health
risk
endpoints,
so
the
lower
bound
of
potential
risks
may
be
as
low
as
zero.

The
first
approach
used
the
range
of
PAR
values
derived
from
consideration
of
five
individual
epidemiology
studies.
This
range
was
used
at
the
basis
for
the
Stage
1
and
the
proposed
Stage
2
economic
analyses
(
i.
e.,
2
percent
to
17
percent)
(
USEPA
2003a).
183
The
second
approach
used
results
from
the
Villanueva
et
al.
(
2003)
meta­
analysis.
This
study
develops
a
combined
Odds
Ratio
(
OR)
of
1.2
that
reflects
the
ever­
exposed
category
for
both
sexes
from
all
studies
considered
in
the
meta­
analysis
and
yields
a
PAR
value
of
approximately
16
percent.

The
third
approach
used
the
Villanueva
et
al.
(
2004)
pooled
data
analysis
to
develop
a
dose­
response
relationship
for
OR
as
a
function
of
average
TTHM
exposure.
Using
the
results
from
this
approach,
EPA
estimates
a
PAR
value
of
approximately
17
percent.

EPA
used
the
PAR
values
from
all
three
approaches
to
estimate
the
number
of
bladder
cancer
cases
ultimately
avoided
annually
as
a
result
of
the
Stage
2
DBPR.
To
quantify
the
reduction
in
cases,
EPA
assumed
a
linear
relationship
between
average
DBP
concentration
and
relative
risk
of
bladder
cancer.
Because
of
this,
EPA
considers
these
estimates
to
be
an
upper
bound
on
the
annual
reduction
in
bladder
cancer
cases
due
to
the
rule.

A
lag
period
(
i.
e.,
cessation
lag)
exists
between
when
reduction
in
exposure
to
a
carcinogen
occurs
and
when
the
full
risk
reduction
benefit
of
that
exposure
reduction
is
realized
by
exposed
individuals.
No
data
are
available
that
address
the
rate
of
achieving
bladder
cancer
benefits
resulting
from
DBP
reductions.
Consequently,
EPA
used
data
from
epidemiological
studies
that
address
exposure
reduction
to
cigarette
smoke
and
arsenic
to
generate
three
possible
cessation
lag
functions
for
bladder
cancer
and
DBPs.
The
cessation
lag
functions
are
used
in
conjunction
with
the
rule
implementation
schedule
to
project
the
number
of
bladder
cancer
cases
avoided
each
year
as
a
result
of
the
Stage
2
DBPR.

Although
EPA
hadused
three
equally
valid
approaches
for
estimating
PAR,
for
simplicity's
sake,
EPA
used
the
Villanueva
et
al.
(
2003)
study
to
calculate
the
annual
benefits
of
the
Stage
2
DBPR.
The
benefits
estimates
derived
from
Villanueva
et
al.
(
2003)
capture
a
substantial
portion
of
the
overall
range
of
results,
reflecting
the
uncertainty
in
both
the
underlying
OR
and
PAR
184
values,
as
well
as
the
uncertainty
in
DBP
reductions
for
Stage
2.

To
assign
a
monetary
value
to
avoided
bladder
cancer
cases,
EPA
used
the
value
of
a
statistical
life
(
VSL)
for
fatal
cases
and
used
two
alternate
estimates
of
willingness­
to­
pay
to
avoid
non­
fatal
cases
(
one
based
on
curable
lymphoma
and
the
other
based
on
chronic
bronchitis).

Significant
value
could
be
associated
with
the
avoided
fetal
losses
estimated
in
the
illustrative
calculation,
but
EPA
is
unable
at
this
time
to
develop
a
specific
estimate
of
this
valueEPA
believes
additional
benefits
from
this
rule
could
come
from
a
reduction
in
potential
reproductive
and
developmental
risks.
See
Chapter
6
of
the
EA
for
more
information
on
estimating
benefits
(
USEPA
2005a).

3.
Estimating
costs
Analyzing
costs
for
systems
to
comply
with
the
Stage
2
DBPR
included
identifying
and
costing
treatment
process
improvements
that
systems
will
make,
as
well
as
estimating
the
costs
to
implement
the
rule,
conduct
IDSEs,
prepare
monitoring
plans,
perform
additional
routine
monitoring,
and
evaluate
significant
DBP
excursion
events.
The
cost
analysis
for
States/
Primacy
Agencies
included
estimates
of
the
labor
burdens
for
training
employees
on
the
requirements
of
the
Stage
2
DBPR,
responding
to
PWS
reports,
and
record
keeping.

All
treatment
costs
are
based
on
mean
unit
cost
estimates
for
advanced
technologies
and
chloramines.
Derivation
of
unit
costs
are
described
in
detail
in
Technologies
and
Costs
for
the
Control
of
Microbial
ContaminantsFinal
Long
Term
2
Enhanced
Surface
Water
Treatment
Rule
and
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule
(
USEPA
2005ig).
Unit
costs
(
capital
and
O&
M)
for
each
of
nine
system
size
categories
are
calculated
using
mean
design
and
average
daily
flows
values.
The
unit
costs
are
then
combined
with
the
predicted
number
of
plants
selecting
each
technology
to
produce
national
treatment
cost
estimates.

Non­
treatment
costs
for
implementation,
the
IDSE,
monitoring
plans,
additional
routine
185
monitoring,
and
operational
evaluations
are
based
on
estimates
of
labor
hours
for
performing
these
activities
and
on
laboratory
costs.

While
systems
vary
with
respect
to
many
of
the
input
parameters
to
the
Stage
2
DBPR
cost
analysis
(
e.
g.,
plants
per
system,
population
served,
flow
per
population,
labor
rates),
EPA
believes
that
mean
values
for
the
various
input
parameters
are
appropriate
to
generate
the
best
estimate
of
national
costs
for
the
rule.
Uncertainty
in
the
national
average
unit
capital
and
O&
M
costs
for
the
various
technologies
has
been
incorporated
into
the
cost
analysis
(
using
Monte
Carlo
simulation
procedures).
Costs
of
the
Stage
2
DBPR
are
estimated
at
both
mean
and
90
percent
confidence
bound
values.

EPA
assumes
that
systems
will,
to
the
extent
possible,
pass
cost
increases
on
to
their
customers
through
increases
in
water
rates.
Consequently,
EPA
has
also
estimated
annual
household
cost
increases
for
the
Stage
2
DBPR.
This
analysis
includes
costs
for
all
households
served
by
systems
subject
to
the
rule,
costs
just
for
those
households
served
by
systems
actually
changing
treatment
technologies
to
comply
with
the
rule,
costs
for
households
served
by
small
systems,
and
costs
for
systems
served
by
surface
water
and
ground
water
sources.

4.
Comparing
regulatory
alternatives
Through
the
analyses
summarized
in
this
section,
EPA
assessed
the
benefits
and
costs
of
the
four
regulatory
alternatives
described
previously.
Succeeding
sections
of
this
preamble
present
the
results
of
these
analyses.
As
recommended
by
the
Advisory
Committee,
EPA
is
establishing
the
preferred
regulatory
alternative
for
today's
Stage
2
DBPR.
This
regulation
will
reduce
peak
DBP
concentrations
in
distribution
systems
through
requiring
compliance
determinations
with
existing
TTHM
and
HAA5
MCLs
using
the
LRAA.
Further,
the
IDSE
will
ensure
that
systems
identify
compliance
monitoring
sites
that
reflect
high
DBP
levels.
EPA
believes
that
these
provision
are
appropriate
given
the
association
of
DBPs
with
cancer,
as
well
as
186
potential
reproductive
and
developmental
health
effects.

Alternative
1
would
have
established
the
same
DBP
regulations
as
the
preferred
alternative,
and
would
have
lowered
the
bromate
MCL
from
0.010
to
0.005
mg/
L.
The
Advisory
Committee
did
not
recommend
and
EPA
did
not
establish
this
alternative
because
it
could
have
an
adverse
effect
on
microbial
protection.
The
lower
bromate
MCL
could
cause
many
systems
to
reduce
or
eliminate
the
use
of
ozone,
which
is
an
effective
disinfectant
for
a
broad
spectrum
of
microbial
pathogens,
including
microorganisms
like
Cryptosporidium
that
are
resistant
to
chlorine.

Alternative
2
would
have
prohibited
any
single
sample
from
exceeding
the
TTHM
or
HAA5
MCL.
This
is
significantly
more
stringent
than
the
preferred
alternative
and
would
likely
require
a
large
fraction
of
surface
water
systems
to
switch
from
their
current
treatment
practices
to
more
expensive
advanced
technologies.
Consistent
with
the
Advisory
Committee,
EPA
does
not
believe
such
a
drastic
shift
is
warranted
at
this
time.

Similarly,
Alternative
3,
which
would
decrease
TTHM
and
HAA5
MCLs
to
0.040
mg/
L
and
0.030
mg/
L,
respectively,
and
would
require
a
significant
portion
of
surface
water
systems
to
implement
expensive
advanced
technologies
in
place
of
their
existing
treatment.
Further,

compliance
with
TTHM
and
HAA5
MCLs
under
this
alternative
would
be
based
on
the
RAA,

which
does
not
specifically
address
DBP
peaks
in
the
distribution
system
as
the
LRAA,
in
conjunction
with
the
IDSE,
are
designed
to
do.
Based
on
these
considerations,
EPA
and
the
Advisory
Committee
did
not
favor
this
alternative.

C.
Benefits
of
the
Stage
2
DBPR
The
benefits
analysis
for
the
Stage
2
DBPR
includes
a
description
of
non­
quantified
benefits,
calculations
of
quantified
benefits,
and
a
discussion
of
when
benefits
will
occur
after
187
today's
final
rule
is
implemented.
An
overview
of
the
methods
used
to
determine
benefits
is
provided
in
Section
VI.
B.
More
detail
can
be
found
in
the
final
EA.
A
summary
of
benefits
for
the
Stage
2
DBPR
is
given
in
this
section.

1.
Nonquantified
benefits
Non­
quantified
benefits
of
the
Stage
2
DBPR
include
potential
benefits
from
reduced
reproductive
and
developmental
risks,
reduced
risks
of
cancers
other
than
bladder
cancer,
and
improved
water
quality.
EPA
predictsbelieves
that
a
significant
portion
of
the
totaldditional
benefits
from
this
rule
could
come
from
reduction
in
developmental
and
reproductive
health
effects,
although
the
evidence
of
these
effects
as
a
result
of
DBP
exposure
is
uncertain
and
not
strong
enough
to
fully
quantify
risk
or
benefitsa
reduction
in
potential
reproductive
and
developmental
risks.
However,
EPA
does
not
believe
the
available
evidence
provides
an
adequate
basis
for
quantifying
these
potential
risks
in
the
primary
analysis.

Both
toxicology
and
epidemiology
studies
indicate
that
the
other
cancers
aremay
be
associated
with
DBP
exposure
but
currently
there
is
not
enough
data
to
include
them
in
the
primary
analysis.
However,
EPA
believes
that
the
association
between
exposure
to
DBPs
and
colon
and
rectal
cancer
is
possibly
significant,
so
an
analysis
of
benefits
is
presented
as
a
sensitivity
analysis.

To
the
extent
that
the
Stage
2
DBPR
changes
perceptions
of
the
health
risks
associated
with
drinking
water
and
improves
taste
and
odor,
it
may
reduce
actions
such
as
buying
bottled
water
or
installing
filtration
devices.
Any
resulting
cost
savings
would
be
a
regulatory
benefit.

Also,
as
PWSs
move
away
from
conventional
treatment
to
more
advanced
technologies,
other
non­
health
benefits
are
anticipated
besides
better
tasting
and
smelling
water.
For
example,

chlorine
dioxide
is
effective
in
controlling
the
spread
of
zebra
mussels,
an
invasive
species
that
has
caused
significant
ecological
damage
in
some
U.
S.
waterwaysGAC
lowers
nutrient
availability
for
188
bacterial
growth,
produces
a
biologically
more
stable
finished
water,
and
facilitates
management
of
water
quality
in
the
distribution
system.
Since
GAC
also
removes
synthetic
organic
chemicals
(
SOCs),
it
provides
additional
protection
from
exposure
to
chemicals
associated
with
accidental
spills
or
environmental
runoff.

2.
Quantified
benefits
EPA
has
quantified
the
benefits
associated
with
the
expected
reductions
in
the
incidence
of
bladder
cancer.
As
discussed
in
Section
VI.
B,
EPA
used
the
PAR
values
from
all
three
approaches
to
estimate
the
number
of
bladder
cancer
cases
ultimately
avoided
annually
as
a
result
of
the
Stage
2
DBPR,
shown
in
Figure
VI.
C­
1.

Table
VI.
C­
21
summarizes
the
estimated
number
of
bladder
cancer
cases
avoided
as
a
result
of
the
Stage
2
DBPR,
accounting
for
cessation
lag
and
the
rule
implementation
schedule,

and
the
monetized
value
of
those
cases.
The
benefits
in
Table
VI.
C­
21
were
developed
using
the
PAR
value
from
Villanueva
et
al.
(
2003),
as
described
in
Section
VI.
B.
Table
VI.
C­
21
summarizes
the
benefits
for
the
Preferred
Regulatory
Alternative
for
the
Stage
2
DBPR.
Benefits
estimates
for
the
other
regulatory
alternatives
were
derived
using
the
same
methods
as
for
the
Preferred
Regulatory
Alternative
and
are
presented
in
the
EA.

The
confidence
bounds
of
the
results
in
Table
VI.
C­
21
reflect
uncertainty
in
PAR,

uncertainty
in
the
compliance
forecast
and
resulting
reduction
in
DBP
concentrations,
and
cessation
lag.
Confidence
bounds
of
the
monetized
benefits
also
reflect
uncertainty
in
valuation
parameters.
An
estimated
26
percent
of
bladder
cancer
cases
avoided
are
fatal,
and
74
percent
are
non­
fatal
(
USEPA
1999b).
The
monetized
benefits
therefore
reflect
the
estimate
of
avoiding
both
fatal
and
non­
fatal
cancers
in
those
proportions.
189
190
Figure
VI.
C­
1.
Comparison
of
Estimates
of
Annual
Bladder
Cancer
Cases
Ultimately
Avoidable
from
Stage
1
to
Stage
2.
191
Abbreviation:
PAR
=
Population
Attributable
Risk
(
values
shown
are
best
estimates).
CB
=
Confidence
Bound
Notes:
Estimated
annual
cases
ultimately
avoidable
are
based
on
predicted
DBP
reduction
from
Stage
1
to
Stage
2.
Results
shown
assume
that
percent
reduction
in
average
TTHM
concentrations
is
an
indicator
of
percent
reduction
in
concentrations
of
all
DBPs.
Three
contributions
to
the
uncertainty
in
the
estimate
of
the
annual
cases
ultimately
avoidable
by
Stage
2
are
displayed
in
this
exhibit:
(
1)
uncertainty
in
the
approach
used
to
estimate
PAR;
(
2)
uncertainty
in
the
underlying
data
used
to
derive
the
PAR
estimates
for
each
approach,
represented
by
the
95
percent
confidence
intervals
displayed
in
each
horizontal
bar;
and
(
3)
uncertainty
in
the
percent
reduction
in
the
national
average
DBP
levels
achieved
by
Stage
2
is
represented
by
the
lower
90
percent
CB,
best
estimate,
and
upper
90
percent
CB
values
shown
for
each
approach.
For
Approach
1,
the
hatched
boxes
represent
the
2
percent
to
17
percent
range
of
best
estimates
from
the
five
separate
studies
considered.
in
the
Odds
Ratios
underlying
the
PAR
values.
The
estimates
in
boxes
are
the
overall
mean
(
best)
estimates
for
each
approach.

Approach
2
Villanueva
et
al.

(
2003)

(
PAR
=
15.7%)

Approach
3
Villanueva
et
al.

(
2004)

(
PAR
=
17.1%)
Annual
Cases
Ultimately
Avoidable
1,000
2,000
615
317
37
1,060
546
64
1,518
782
92
Approach
1
"
5
Studies"

(
PAR
=
2%­
17%)
159
293
507
275
874
506
1,252
393
724
47
617
319
1,064
80
550
1,523
787
115
DBP
Red.
=
4.5%

(
lower
CB)

DBP
Red.
=
7.8%

(
best
estimate)

DBP
Red.
=
11.2%

(
upper
CB)
0
DBP
Red.
=
4.5%

(
lower
CB)

DBP
Red.
=
7.8%

(
best
estimate)

DBP
Red.
=
11.2%

(
upper
CB)

DBP
Red.
=
4.5%

(
lower
CB)

DBP
Red.
=
7.8%

(
best
estimate)

DBP
Red.
=
11.2%

(
upper
CB)
192
193
Table
VI.
C­
21.
Summary
of
Quantified
Benefits
for
the
Stage
2
DBPR
(
Millions
of
$
2003).
Annual
Average
Cases
Avoided
Discount
Rate,
WTP
for
Non­
Fatal
Cases
Annualized
Benefits
of
Cases
Avoided
Cessation
Lag
Model
Mean
5th
95th
Mean
5th
95th
3
%,
Lymphoma
$
1
,531
$
233
$
3,536
279
103
541
7
%
Lymphoma
$
1,246
$
190
$
2,878
Smoking/
Lung
Cancer
3
%
Bronchitis
$
763
$
165
$
1,692
7
%
Bronchitis
$
621
$
135
$
1,376
3
%,
Lymphoma
$
1,032
$
157
$
2,384
188
61
399
7
%
Lymphoma
$
845
$
129
$
1,950
Smoking/
Bladder
Cancer
3
%
Bronchitis
$
514
$
111
$
1,141
7
%
Bronchitis
$
420
$
91
$
932
3
%,
Lymphoma
$
1,852
$
282
$
4,276
333
138
610
7
%
Lymphoma
$
1,545
$
235
$
3,566
Arsenic/
Bladder
Cancer
3
%
Bronchitis
$
922
$
200
$
2,045
7
%
Bronchitis
$
769
$
167
$
1,704
Notes:
Values
are
discounted
and
annualized
in
2003$.
The
90
percent
confidence
bounds
reflectinterval
for
cases
incorporates
uncertainty
in
PAR,
reduction
in
average
TTHM
and
HAA5
concentrations,
and
cessation
lag,
and.
The
90
percent
confidence
bounds
for
monetized
benefits
reflect
uncertainty
in
monetization
input
(
for
value
of
cases
avoided
only).
Sources:
Summarized
from
detailed
figures
presented
in
Appendix
E
(
Exhibits
E.
17d
and
E.
17g)
and
F
(
Exhibits
F.
2v
and
F.
2w,
F.
3v
and
F.
3w)
(
USEPA
2005a).
inputs
relative
to
mean
cases.
Based
on
TTHM
as
an
indicator,
benefits
were
calculated
using
the
Villanueva
et
al.
(
2003)
PAR.
EPA
recognizes
that
benefits
may
be
as
low
as
zero
since
causality
has
not
yet
been
established
between
exposure
to
chlorinated
water
and
bladder
cancer.
Assumes
26
percent
of
cases
are
fatal,
74
percent
are
non­
fatal
(
USEPA
1999b).
Source:
Exhibit
6.1,
USEPA
2005a.

3.
Timing
of
benefits
accrual
EPA
recognizes
that
it
is
unlikely
that
all
cancer
reduction
benefits
would
be
realized
immediately
upon
exposure
reduction.
Rather,
it
is
expected
that
there
will
likely
be
some
transition
period
as
individual
risks
reflective
of
higher
past
exposures
at
the
time
of
rule
implementation
become,
over
time,
more
reflective
of
the
new
lower
exposures.
EPA
developed
a
cessation
lag
models
for
DBPs
from
literature
to
describe
the
delayed
benefits,
in
keeping
with
the
recommendations
of
the
SAB
(
USEPA
2001cd).
TableFigure
VI.
C­
2C
­
2
illustrates
the
effects
of
the
cessation
lag
models.
The
results
from
the
cessation
lag
models
show
that
the
majority
of
the
potential
cases
avoided
occur
within
the
first
several
decades
after
the
rule
is
194
promulgated.
fifteen
years
after
initial
reduced
exposure
to
DBPs.
For
example,
fifteen
years
after
the
exposure
reduction
has
occurred,
the
annual
cases
avoided
will
be
489
for
the
smoking
/
lung
cancer
cessation
lag
model,
329
for
the
smoking
/
bladder
cancer
cessation
lag
model,
and
534
cases
for
the
arsenic
/
bladder
cancer
cessation
lag
model.
These
represent
approximately
84%,

57%,
and
92%,
respectively,
of
the
estimated
581
annual
cases
ultimately
avoidable
by
the
Stage
2
DBPR.
195
Figure
VI.
C­
2.
Comparison
of
Alternative
Cessation
Lag
Models:
Estimates
of
Annual
Cases
Avoided
by
Year
Following
Exposure
Reduction
(
Excluding
Implementation
Schedule).
196
Text
Moved
Here:
1
In
addition
to
the
delay
in
reaching
a
steady­
state
level
of
risk
reduction
as
a
result
of
cessation
lag,
there
is
a
delay
in
attaining
maximum
exposure
reduction
across
the
entire
affected
population
that
results
from
the
Stage
2
DBPR
implementation
schedule.
For
example,
large
surface
water
PWSs
have
threesix
years
from
rule
promulgation
to
meet
the
new
Stage
2
MCLs,

with
an
additionalup
to
a
two­
year
extension
possible
for
capital
improvements.
In
general,
EPA
assumes
that
a
fairly
constant
increment
of
systems
will
complete
installation
of
new
treatment
technologies
each
year,
with
the
last
systems
installing
treatment
by
2016.
The
delay
in
exposure
reduction
resulting
from
the
rule
implementation
schedule
is
incorporated
into
the
benefits
model
by
adjusting
the
cases
avoided
for
the
given
year
and
is
illustrated
in
Table
VI.
C­
2.

End
Of
Moved
Text
197
Table
VI.
C­
2.
Bladder
Cancer
Cases
Avoided
(
TTHM
as
Indicator)
Each
Year
using
Three
Cessation
Lag
Models.

Year
Smoking/
Lung
Cancer
Cessation
Lag
Model
Smoking/
Bladder
Cancer
Cessation
Lag
Model
Arsenic
/
Bladder
Cancer
Cessation
Lag
Model
Total
Percent1
Total
Percent1
Total
Percent1
1
0
0%
0
0%
0
0%
2
0
0%
0
0%
0
0%
3
0
0%
0
0%
0
0%
4
0
0%
0
0%
0
0%
5
0
0%
0
0%
0
0%
6
24
4%
23
4%
45
8%
7
612
11%
534
9%
109110
19%
8
1101
19%
90
16%
1867
32%
9
16870
29%
1312
23%
2735
478%
10
21820
38%
15961
28%
3314
578%
11
2635
46%
1834
32%
3769
65%
12
3035
53%
2024
35%
40912
71%
13
33941
59%
2201
38%
4358
756%
14
36971
64%
2367
41%
4568
79%
15
3946
68%
2501
43%
4735
82%
16
4146
72%
2645
46%
4868
84%
17
4313
75%
2768
48%
4979
86%
18
4468
77%
2889
50%
5079
88%
19
45960
79%
299301
52%
5146
89%
20
46971
81%
3101
54%
5213
90%
21
47981
83%
3201
55%
5278
91%
22
4879
84%
32930
57%
5313
92%
23
4956
86%
3389
59%
5357
93%
24
5013
87%
3467
60%
53941
93%
25
5079
88%
3545
61%
5424
94%
1PercentNotes:
Percent
of
annual
cases
ultimately
avoidable
cases
achieved
during
each
of
the
first
25
years.

Text
Was
Moved
From
Here:
1
The
benefits
model
estimates
581
(
90%
CB
=
229­
1,079)
annual
cases
ultimately
avoidable
using
the
Villanueva
et
al.
(
2003)
PAR
inputs
and
including
uncertainty
in
these
and
DBP
reductions.
EPA
recognizes
that
benefits
may
be
as
low
as
zero
since
causality
has
not
yet
been
established
between
exposure
to
chlorinated
water
and
bladder
cancer.
Source:
Summarized
from
detailed
results
presented
in
Exhibits
E.
38a,
E.
38e
and
E.
38i,
USEPA
2005a.

D.
Costs
of
the
Stage
2
DBPR
National
costs
include
those
of
treatment
changes
to
comply
with
the
rule
as
well
as
nontreatment
costs
such
as
for
Initial
Distribution
System
Evaluations
(
IDSEs),
additional
routine
monitoring,
and
operational
evaluations.
The
methodology
used
to
estimate
costs
is
described
in
Section
VI.
B.
More
detail
is
provided
in
the
EA
(
USEPA
2005a).
The
remainder
of
this
section
198
presents
summarized
results
of
EPA's
cost
analysis
for
total
annualized
present
value
costs,
PWS
costs,
State/
Primacy
agency
costs,
and
non­
quantified
costs.

1.
Total
annualized
present
value
costs
Tables
VI.
D­
1
and
VI.
D­
2
summarize
the
average
annualized
costs
for
the
Stage
2
DBPR
Preferred
Regulatory
Alternative
at
3
and
7
percent
discount
rates,
respectively.
System
costs
range
from
approximately
$
595
to
$
114$
101
million
annually
at
a
3
percent
discount
rate,
with
a
mean
estimate
of
approximately
$
8677
million
per
year.
The
mean
and
range
of
annualized
costs
are
similar
at
a
7
percent
discount
rate.
State
costs
are
estimated
to
be
between
$
1.70
and
$
1.71
million
per
year
depending
on
the
discount
rate.
These
estimates
are
annualized
starting
with
the
year
of
promulgation.
Actual
dollar
costs
during
years
when
most
treatment
changes
are
expected
to
occur
would
be
somewhat
higher
(
the
same
is
true
for
benefits
that
occur
in
the
future).
199
Total
System
Costs
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)
Implementation
IDSE
Monitoring
Plans
Monitoring
Significant
Excursion
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)

<
10,000
$
4.21
$
2.32
$
6.23
$
6.10
$
3.41
$
8.83
$
0.12
$
0.93
$
0.05
­$
0.07
$
0.02
$
11.34
$
6.76
$
16.10
>
10,000
$
20.60
$
11.22
$
28.75
$
14.33
$
9.03
$
21.55
$
0.09
$
1.59
$
0.03
­$
1.14
$
0.11
$
35.61
$
20.93
$
50.97
<
10,000
$
0.27
$
0.15
$
0.40
$
0.57
$
0.32
$
0.82
$
0.01
$
0.00
$
0.00
$
0.02
$
0.00
$
0.86
$
0.49
$
1.25
>
10,000
$
0.04
$
0.02
$
0.06
$
0.03
$
0.02
$
0.04
$
0.00
$
0.00
$
0.00
$
0.00
$
0.00
$
0.08
$
0.05
$
0.11
<
10,000
$
7.41
$
6.13
$
8.70
$
7.20
$
6.60
$
7.79
$
0.30
$
0.29
$
0.08
$
1.05
$
0.00
$
16.33
$
14.45
$
18.21
>
10,000
$
4.87
$
4.37
$
5.36
$
6.00
$
5.64
$
6.37
$
0.05
$
0.10
$
0.02
$
0.00
$
0.00
$
11.04
$
10.18
$
11.90
<
10,000
$
0.57
$
0.48
$
0.65
$
0.75
$
0.69
$
0.81
$
0.06
$
0.00
$
0.01
$
0.42
$
0.00
$
1.80
$
1.65
$
1.95
>
10,000
$
0.01
$
0.01
$
0.01
$
0.01
$
0.01
$
0.01
$
0.00
$
0.00
$
0.00
$
0.01
$
0.00
$
0.03
$
0.02
$
0.03
TOTAL
$
37.97
$
24.69
$
50.17
$
34.98
$
25.72
$
46.22
$
0.62
$
2.91
$
0.19
$
0.28
$
0.12
$
77.08
$
54.53
$
100.51
$
1.71
$
78.80
$
56.24
$
102.22
Total
Costs
of
the
Rule
Surface
Water
CWSs
Surface
Water
NTNCWSs
Mean
Value
90
Percent
Confidence
Bound
Capital
Costs
O&
M
Costs
Mean
Value
Ground
Water
CWSs
90
Percent
Confidence
Bound
System
Costs
90
Percent
Confidence
Bound
State
Costs
Ground
Water
NTNCWSs
System
Size
(
Population
Served)
Non­
Treatment
Costs
(
Point
Estimate)
Mean
Value
Mean
Value
90
Percent
Confidence
Bound
Table
VI.
D­
1.
Total
Annualized
Costs
for
Stage
2
DBPR
Activities
($
Millions/
Year,
3
Percent
Discount
Rate).

Notes:
Detail
may
not
add
due
to
independent
rounding.
90
percent
confidence
bound
reflects
uncertainty
in
technology
compliance
forecast
and
unit
treatment
costs.

Estimates
are
discounted
to
2003,
and
given
in
2003
dollars.

Source:
Exhibit
7.5a,
USEPA
2005a.
200
Total
System
Costs
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)
Implementation
IDSE
Monitoring
Plans
Monitoring
Significant
Excursion
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)

<
10,000
$
4.53
$
2.50
$
6.71
$
4.86
$
2.72
$
7.04
$
0.15
$
1.16
$
0.06
­$
0.06
$
0.01
$
10.72
$
6.54
$
15.08
>
10,000
$
23.00
$
12.53
$
32.10
$
11.66
$
7.35
$
17.54
$
0.11
$
2.06
$
0.04
­$
0.90
$
0.08
$
36.06
$
21.27
$
51.03
<
10,000
$
0.29
$
0.16
$
0.43
$
0.45
$
0.25
$
0.66
$
0.01
$
0.00
$
0.00
$
0.01
$
0.00
$
0.76
$
0.43
$
1.11
>
10,000
$
0.05
$
0.03
$
0.07
$
0.02
$
0.01
$
0.03
$
0.00
$
0.00
$
0.00
$
0.00
$
0.00
$
0.08
$
0.05
$
0.11
<
10,000
$
7.98
$
6.60
$
9.37
$
5.74
$
5.26
$
6.21
$
0.38
$
0.36
$
0.09
$
0.84
$
0.00
$
15.38
$
13.53
$
17.24
>
10,000
$
5.39
$
4.84
$
5.94
$
4.87
$
4.57
$
5.16
$
0.06
$
0.13
$
0.02
$
0.00
$
0.00
$
10.46
$
9.62
$
11.31
<
10,000
$
0.61
$
0.51
$
0.70
$
0.60
$
0.55
$
0.65
$
0.07
$
0.00
$
0.01
$
0.33
$
0.00
$
1.62
$
1.48
$
1.77
>
10,000
$
0.01
$
0.01
$
0.01
$
0.01
$
0.01
$
0.01
$
0.00
$
0.00
$
0.00
$
0.01
$
0.00
$
0.02
$
0.02
$
0.02
TOTAL
$
41.86
$
27.16
$
55.33
$
28.21
$
20.73
$
37.29
$
0.78
$
3.71
$
0.23
$
0.23
$
0.10
$
75.11
$
52.94
$
97.67
$
1.70
$
76.81
$
54.64
$
99.36
Ground
Water
NTNCWSs
System
Size
(
Population
Served)
Non­
Treatment
Costs
(
Point
Estimate)
Mean
Value
Mean
Value
90
Percent
Confidence
Bound
90
Percent
Confidence
Bound
System
Costs
90
Percent
Confidence
Bound
State
Costs
Total
Costs
of
the
Rule
Surface
Water
CWSs
Surface
Water
NTNCWSs
Mean
Value
90
Percent
Confidence
Bound
Capital
Costs
O&
M
Costs
Mean
Value
Ground
Water
CWSs
Table
VI.
D­
2.
Total
Annualized
Costs
for
Stage
2
DBPR
Activities
($
Millions/
Year,
7
Percent
Discount
Rate).

Notes:
Detail
may
not
add
due
to
independent
rounding.
90
percent
confidence
bound
reflects
uncertainty
in
technology
compliance
forecast
and
unit
treatment
costs.

Estimates
are
discounted
to
2003,
and
given
in
2003
dollars.

Source:
Exhibit
7.5b,
USEPA
2005a.
201
2.
PWS
costs
PWS
costs
for
the
Stage
2
DBPR
include
non­
treatment
costs
of
rule
implementation,

Initial
Distribution
System
Evaluations
(
IDSEs),
Stage
2
DBPR
monitoring
plans,
additional
routine
monitoring,
and
operational
evaluations.
Systems
required
to
install
treatment
to
comply
with
the
MCLs
will
accrue
the
additional
costs
of
treatment
installation
as
well
as
operation
and
maintenance.
Significant
PWS
costs
for
IDSEs,
treatment,
and
monitoring
are
described
in
this
section,
along
with
a
sensitivity
analysis.

a.
IDSE
costs.
Costs
and
burden
associated
with
IDSE
activities
differ
depending
on
whether
or
not
the
system
performs
the
IDSE
and,
if
so,
which
option
a
system
chooses.
All
systems
performing
the
IDSE
are
expected
to
incur
some
costs.
EPA's
analysis
allocated
systems
into
five
categories
to
determine
the
costs
of
the
IDSE
 
those
conducting
an
SMPstandard
monitoring,
SSS,
VSS,
40/
30,
and
NTNCWS
not
required
to
do
an
IDSE.
EPA
then
developed
cost
estimates
for
each
option.
Tables
VI.
D­
3,
VI.
D­
4,
and
VI.
D­
5
illustrate
PWS
costs
for
IDSE
for
systems
conducting
an
SMP,
SSS,
and
40/
30,
respectively.
202
Preparation
of
IDSE
Monitoring
Plan
Preparation
of
IDSE
Report
Reporting
Cost
per
Labor
Hour
Number
of
Dual
Sample
Sets
per
System
Hours
per
Sample
Sampling
Cost
per
Labor
Hour
Laboratory
Cost
per
Sample
A
B
C
D
E
F
G
H
I=
A*((
B+
C)*
D+
E*(
F*
G+
H))
J=
A*(
B+
C+
E*
F)
K=
J/
2,080
Surface
Water
and
Mixed
CWSs
2,060
4
2
22.55
$
2
1
22.55
$
240
$
1,360,071
$
16,476
7.9
3,823
4
2
24.74
$
8
1
24.74
$
240
$
8,664,294
$
53,522
25.7
1,888
4
2
30.51
$
16
1
25.34
$
240
$
8,361,031
$
41,536
20.0
1,524
8
4
31.08
$
48
1
26.05
$
210
$
17,835,921
$
91,440
44.0
436
8
8
32.64
$
96
1
28.00
$
210
$
10,189,487
$
48,832
23.5
63
12
12
35.25
$
144
1
31.26
$
210
$
2,242,006
$
10,584
5.1
14
16
24
35.25
$
192
1
31.26
$
210
$
668,246
$
3,248
1.6
1
24
24
35.25
$
240
1
31.26
$
210
$
59,594
$
288
0.1
9,809
49,380,649
$
265,926
127.8
Disinfecting
Ground
Water
Only
CWSs
752
4
2
22.35
$
2
1
22.35
$
240
$
495,114
$
6,012
2.9
1,956
4
2
24.86
$
8
1
24.86
$
240
$
4,435,321
$
27,378
13.2
240
8
8
31.08
$
24
1
26.05
$
210
$
1,477,430
$
9,590
4.6
18
12
12
35.25
$
32
1
31.26
$
210
$
152,514
$
997
0.5
1
16
24
35.25
$
48
1
31.26
$
210
$
11,576
$
78
0.0
2,966
6,571,956
$
44,056
21.2
Surface
Water
and
Mixed
NTNCWSs
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
4
8
4
31.08
$
48
1
26.05
$
210
$
46,813
$
240
0.1
1
8
8
35.25
$
96
1
31.26
$
210
$
23,725
$
112
0.1
0
12
12
N/
A
144
1
N/
A
210
$
­
$
­
­

0
16
24
N/
A
192
1
N/
A
210
$
­
$
­
­

0
24
24
N/
A
240
1
N/
A
210
$
­
$
­
­

5
70,538
$
352
0.2
Disinfecting
Ground
Water
Only
NTNCWSs
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
1
8
8
31.08
$
24
1
26.05
$
210
$
3,759
$
24
0.0
0
12
12
35.25
$
32
1
31.26
$
210
$
2,484
$
16
0.0
0
16
24
N/
A
48
1
N/
A
210
$
­
$
­
­

1
6,243
$
41
0.0
Grand
Totals
12,780
56,029,386
$
310,375
149.2
National
Totals
500­
9,999
10,000­
99,999
100,000­
499,999
>
500,000
1,000,000­
4,999,999
 
5
 
National
Totals
<
500
3,300­
9,999
10,000­
49,999
50,000­
249,999
250,000­
999,999
>
500,000
National
Totals
<
500
500­
3,299
<
500
500­
9,999
10,000­
99,999
100,000­
499,999
250,000­
999,999
1,000,000­
4,999,999
 
5
 
National
Totals
500­
3,299
3,300­
9,999
10,000­
49,999
50,000­
249,999
Total
Cost
Total
Burden
(
Hours)
Total
Burden
(
FTEs)

<
500
Size
Category
Total
Number
of
Systems
That
Monitor
Develop
IDSE
monitoring
plan
and
report
Sampling
Table
VI.
D­
3.
IDSE
Costs
for
Systems
Using
Standard
Monitoring.

Notes:
Detail
my
not
add
due
to
independent
rounding.
Shaded
areas
represent
systems
that
are
not
subject
to
IDSE
requirements.
1
FTE
=
2,080
hours
(
40
hours/
week,
52
weeks/
year)
Source:
Exhibit
H.
4,
USEPA,
2005a.
203
Number
of
Systems
Qualifying
for
SSS
Preparation
of
IDSE
Study
Plan
Conduct
Study
Preparation
of
IDSE
Study
Report
Cost
per
Labor
Hour
Total
Cost
Total
Burden
(
Hours)
Total
Burden
(
FTEs)

A
B
C
D
E
F
=
A*(
B+
C+
D)*
E
G
=
A*(
B+
C+
D)
H
=
G/
2,080
­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

23
20
40
20
32.64
$
60,060
$
1,840
0.9
7
20
40
20
35.25
$
19,739
$
560
0.3
1
20
40
20
35.25
$
2,820
$
80
0.0
­
­
­
­
­
$
­
$
­
­

National
Total
31
82,618
$
2,480
1.2
­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

2
20
40
20
35.25
$
5,640
$
160
0.1
­
­
­
­
­
$
­
$
­
­

National
Total
2
5,640
$
160
0.1
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

National
Total
­
­
$
­
­

N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

­
­
­
­
­
$
­
$
­
­

National
Total
­
­
$
­
­

Grand
Totals
33
88,258
$
2,640
1.3
500­
9,999
10,000­
99,999
100,000­
499,999
>
500,000
1,000,000­
4,999,999
 
5
 
Disinfecting
Ground
Water
Only
NTNCWSs
<
500
3,300­
9,999
10,000­
49,999
50,000­
249,999
250,000­
999,999
>
500,000
Surface
Water
and
Mixed
NTNCWSs
<
500
500­
3,299
<
500
500­
9,999
10,000­
99,999
100,000­
499,999
250,000­
999,999
1,000,000­
4,999,999
 
5
 
Disinfecting
Ground
Water
Only
CWSs
500­
3,299
3,300­
9,999
10,000­
49,999
50,000­
249,999
Size
Category
Surface
Water
and
Mixed
CWSs
<
500
Table
VI.
D­
4.
IDSE
Costs
for
Systems
Using
SSSs.

Notes:
Detail
my
not
add
due
to
independent
rounding.
Shaded
areas
represent
systems
that
are
not
subject
to
IDSE
requirements.
SSS
=
System
Specific
Study.
Source:
Exhibit
H.
5,
USEPA
2005a.
204
Systems
Receiving
40/
30
Certification
but
Adding
Stage
2
site(
s)
Hours
per
System
Number
of
Systems
Receiving
40/
30
Certification
Reporting
Hours
per
System
A
B
C
D
E
F
=
(
A*
B+
C*
D)*
E
G
=
A*
B+
C*
D
H
=
G/
2,080
­
1
­
1
22.55
$
­
$
­
­

­
3
235
1
24.74
$
5,814
$
235
0.1
154
3
154
1
30.51
$
18,795
$
616
0.3
­
8
249
2
31.08
$
15,478
$
498
0.2
75
8
75
2
32.64
$
24,481
$
750
0.4
11
8
11
2
35.25
$
3,877
$
110
0.1
2
8
2
2
35.25
$
705
$
20
0.0
­
8
­
2
35.25
$
­
$
­
­

National
Total
242
726
69,150
$
2,229
1.1
­
1
­
1
22.35
$
­
$
­
­

9,094
3
9,094
1
24.86
$
904,287
$
36,376
17.5
1,118
8
1,118
2
31.08
$
347,474
$
11,180
5.4
­
8
40
2
35.25
$
2,820
$
80
0.0
­
8
5
2
35.25
$
352
$
10
0.0
National
Total
10,212
10,257
1,254,934
$
47,646
22.9
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
­
8
1
2
31.08
$
62
$
2
0.0
­
8
­
2
35.25
$
­
$
­
­

­
8
­
2
N/
A
­
$
­
­

­
8
­
2
N/
A
­
$
­
­

­
8
­
2
N/
A
­
$
­
­

National
Total
­
1
62
$
2
0.0
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
N/
A
3
8
3
2
31.08
$
932
$
30
0.0
­
8
­
3
35.25
$
­
$
­
­

­
8
­
6
N/
A
­
$
­
­

National
Total
3
3
932
$
30
0.0
Grand
Totals
10,457
10,987
1,325,079
$
49,907
24.0
>
500,000
<
500
500­
9,999
10,000­
99,999
100,000­
499,999
250,000­
999,999
1,000,000­
4,999,999
 
5
 
Disinfecting
Ground
Water
Only
NTNCWSs
500­
3,299
3,300­
9,999
10,000­
49,999
50,000­
249,999
100,000­
499,999
>
500,000
Surface
Water
and
Mixed
NTNCWSs
<
500
Disinfecting
Ground
Water
Only
CWSs
<
500
500­
9,999
10,000­
99,999
50,000­
249,999
250,000­
999,999
1,000,000­
4,999,999
 
5
 
<
500
500­
3,299
3,300­
9,999
10,000­
49,999
Total
Cost
Total
Burden
(
Hours)
Total
Burden
(
FTEs)

Surface
Water
and
Mixed
CWSs
Size
Category
Selecting
Additional
Sites
Preparing
IDSE
Certification
Cost
per
Labor
Hour
Table
VI.
D­
5.
IDSE
Costs
Systems
Qualifying
for
the
40/
30
Certification.

Notes:
Shaded
areas
represent
systems
that
are
not
subject
to
IDSE
requirements.
Source:
Exhibit
H.
6,
USEPA,
2005a.
205
206
b.
PWS
treatment
costs.
The
number
of
plants
changing
treatment
as
a
result
of
the
Stage
2
DBPR
and
which
technology
various
systems
will
install
are
determined
from
the
compliance
forecast.
The
percent
of
systems
predicted
to
make
treatment
technology
changes
and
the
technologies
predicted
to
be
in
place
after
implementation
of
the
Stage
2
DBPR
are
shown
in
Table
VI.
D­
6.
The
cost
model
includes
estimates
for
the
cost
of
each
technology;
the
results
of
the
cost
model
for
PWS
treatment
costs
are
summarized
in
Table
VI.
D­
7.
207
Source
System
Classification
System
Size
(
Population
Served)
CLM
Only
Chlorine
Dioxide
UV
Ozone
MF/
UF
GAC10
GAC
10
+
Alternative
Disinfectants
GAC
20
GAC
20
+
Alternative
Disinfectants
Membranes
Total
Converting
to
CLM
Total
Percent
of
Plants
Changing
Technology
<
100
1.9%
7.1%
0.0%
0.0%
1.2%
0.0%
5.4%
10.2%

100­
499
4.1%
0.5%
2.5%
0.0%
0.0%
0.0%
1.3%
0.1%
6.5%
8.4%

500­
999
4.1%
0.5%
2.5%
0.0%
0.0%
0.0%
1.3%
0.1%
6.5%
8.4%

1,000­
3,300
4.2%
1.1%
2.2%
0.0%
0.0%
0.0%
1.3%
0.0%
7.2%
8.8%

3,301­
9,999
4.2%
1.1%
2.2%
0.0%
0.0%
0.0%
1.3%
0.0%
7.2%
8.8%

10,000­
49,999
8.6%
0.3%
3.6%
0.0%
0.0%
0.0%
1.7%
0.3%
0.0%
0.0%
10.3%
14.6%

50,000­
99,999
8.6%
0.3%
3.6%
0.0%
0.0%
0.0%
1.7%
0.3%
0.0%
0.0%
10.3%
14.6%

100,000­
999,999
8.6%
0.3%
3.6%
0.0%
0.0%
0.0%
1.7%
0.3%
0.0%
0.0%
10.3%
14.6%

1,000,000+
8.6%
0.3%
3.6%
0.0%
0.0%
0.0%
1.7%
0.3%
0.0%
0.0%
10.3%
14.6%

All
Sizes
5.8%
0.6%
3.1%
0.0%
0.0%
0.0%
0.6%
0.1%
0.8%
0.0%
8.2%
11.1%

<
100
1.9%
7.1%
0.0%
0.0%
1.2%
0.0%
5.4%
10.2%

100­
499
4.1%
0.5%
2.5%
0.0%
0.0%
0.0%
1.3%
0.1%
6.5%
8.4%

500­
999
4.1%
0.5%
2.5%
0.0%
0.0%
0.0%
1.3%
0.1%
6.5%
8.4%

1,000­
3,300
4.2%
1.1%
2.2%
0.0%
0.0%
0.0%
1.3%
0.0%
7.2%
8.8%

3,301­
9,999
4.2%
1.1%
2.2%
0.0%
0.0%
0.0%
1.3%
0.0%
7.2%
8.8%

10,000­
49,999
8.6%
0.3%
3.6%
0.0%
0.0%
0.0%
1.7%
0.3%
0.0%
0.0%
10.3%
14.6%

50,000­
99,999
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%

100,000­
999,999
8.6%
0.3%
3.6%
0.0%
0.0%
0.0%
1.7%
0.3%
0.0%
0.0%
10.3%
14.6%

1,000,000+
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%
­
%

All
Sizes
3.5%
0.4%
3.8%
0.0%
0.0%
0.0%
0.0%
0.0%
1.2%
0.0%
6.3%
9.0%

<
100
1.0%
1.1%
0.0%
0.4%
0.0%
2.1%
2.4%

100­
499
1.4%
1.6%
0.0%
0.2%
0.0%
3.0%
3.2%

500­
999
1.4%
1.6%
0.0%
0.2%
0.0%
3.0%
3.2%

1,000­
3,300
1.1%
1.6%
0.0%
0.0%
0.0%
2.7%
2.7%

3,301­
9,999
1.1%
1.6%
0.0%
0.0%
0.0%
2.7%
2.7%

10,000­
49,999
1.4%
0.3%
0.2%
0.2%
2.0%
2.1%

50,000­
99,999
1.4%
0.3%
0.2%
0.2%
2.0%
2.1%

100,000­
999,999
1.3%
0.3%
0.1%
0.2%
1.9%
2.0%

1,000,000+
1.4%
0.3%
0.1%
0.2%
2.0%
2.1%

All
Sizes
1.3%
1.3%
0.0%
0.2%
0.0%
2.6%
2.8%

<
100
1.0%
1.1%
0.0%
0.4%
0.0%
2.1%
2.4%

100­
499
1.4%
1.6%
0.0%
0.2%
0.0%
3.0%
3.2%

500­
999
1.4%
1.6%
0.0%
0.2%
0.0%
3.0%
3.2%

1,000­
3,300
1.1%
1.6%
0.0%
0.0%
0.0%
2.7%
2.7%

3,301­
9,999
1.1%
1.6%
0.0%
0.0%
0.0%
2.7%
2.7%

10,000­
49,999
1.4%
0.3%
0.2%
0.2%
2.0%
2.1%

50,000­
99,999
1.4%
0.3%
0.2%
0.2%
2.0%
2.1%

100,000­
999,999
1.3%
0.3%
0.1%
0.2%
1.9%
2.0%

1,000,000+
­
%
­
%
­
%
­
%
­
%
­
%

All
Sizes
1.2%
1.4%
0.0%
0.3%
0.0%
2.5%
2.8%

Surface
Water
CWSs
NTNCWSs
Ground
Water
CWSs
NTNCWSs
Table
VI.
D­
6.
Percent
of
Plants
Changing
to
Various
Treatment
Technologies
as
a
Result
of
the
Stage
2
DBPR
(
Stage
2
DBPR
Treatment
Technology
Selection
Deltas).

Notes:
Detail
may
not
add
due
to
independent
rounding.
208
Source:
Summarized
from
detailed
results
presented
in
Exhibits
5.11a­
d
and
5.14a­
d,
USEPA
2005a.
209
210
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)
Lower
(
5th
%
tile)
Upper
(
95th
%
tile)

<
100
1.09
$
1.07
$
0.58
$
1.68
$
0.20
$
0.20
$
0.11
$
0.29
$

100­
499
3.27
$
3.22
$
1.77
$
4.94
$
0.82
$
0.82
$
0.46
$
1.19
$

500­
999
3.86
$
3.78
$
2.08
$
5.89
$
0.61
$
0.61
$
0.34
$
0.88
$

1,000­
3,299
24.39
$
24.27
$
13.37
$
36.07
$
3.36
$
3.36
$
1.88
$
4.86
$

3,300­
9,999
62.23
$
61.92
$
34.42
$
91.81
$
5.32
$
5.34
$
2.97
$
7.70
$

10,000­
49,999
113.20
$
113.98
$
62.72
$
157.05
$
6.04
$
6.00
$
3.74
$
8.66
$

50,000­
99,999
67.40
$
68.08
$
37.41
$
93.50
$
3.41
$
3.36
$
2.13
$
4.95
$

100,000­
999,999
183.98
$
186.24
$
98.21
$
257.75
$
8.17
$
7.87
$
5.21
$
12.52
$

1,000,000+
86.04
$
86.46
$
47.14
$
120.41
$
4.91
$
4.65
$
3.11
$
7.73
$

All
Sizes
545.44
$
549.03
$
297.70
$
769.10
$
32.84
$
32.21
$
19.95
$
48.78
$

<
100
0.67
$
0.66
$
0.36
$
1.03
$
0.12
$
0.12
$
0.07
$
0.17
$

100­
499
1.32
$
1.31
$
0.72
$
2.00
$
0.33
$
0.33
$
0.19
$
0.48
$

500­
999
0.85
$
0.84
$
0.46
$
1.30
$
0.13
$
0.13
$
0.07
$
0.20
$

1,000­
3,299
1.89
$
1.88
$
1.04
$
2.80
$
0.26
$
0.26
$
0.15
$
0.38
$

3,300­
9,999
1.29
$
1.28
$
0.71
$
1.90
$
0.11
$
0.11
$
0.06
$
0.16
$

10,000­
49,999
0.55
$
0.55
$
0.30
$
0.76
$
0.03
$
0.03
$
0.02
$
0.04
$

50,000­
99,999
­
$
­
$
­
$
­
$
­
$
­
$
­
$
­
$

100,000­
999,999
0.41
$
0.41
$
0.22
$
0.57
$
0.02
$
0.02
$
0.01
$
0.03
$

1,000,000+
­
$
­
$
­
$
­
$
­
$
­
$
­
$
­
$

All
Sizes
6.99
$
6.95
$
3.82
$
10.36
$
1.00
$
1.00
$
0.56
$
1.46
$

552.43
$
555.97
$
301.52
$
779.46
$
33.85
$
33.22
$
20.52
$
50.24
$

<
100
8.34
$
8.34
$
7.19
$
9.53
$
0.98
$
0.98
$
0.91
$
1.05
$

100­
499
33.19
$
33.18
$
28.04
$
38.38
$
3.68
$
3.68
$
3.38
$
3.98
$

500­
999
20.18
$
20.18
$
17.00
$
23.34
$
1.96
$
1.96
$
1.80
$
2.12
$

1,000­
3,299
39.43
$
39.42
$
32.35
$
46.54
$
3.00
$
3.00
$
2.73
$
3.26
$

3,300­
9,999
65.91
$
65.86
$
53.53
$
78.34
$
2.55
$
2.55
$
2.33
$
2.76
$

10,000­
49,999
59.09
$
59.08
$
53.39
$
64.79
$
5.03
$
5.03
$
4.76
$
5.30
$

50,000­
99,999
14.96
$
14.96
$
13.38
$
16.53
$
1.28
$
1.28
$
1.20
$
1.36
$

100,000­
999,999
29.70
$
29.71
$
26.43
$
32.95
$
2.83
$
2.83
$
2.64
$
3.02
$

1,000,000+
3.38
$
3.38
$
2.97
$
3.79
$
0.43
$
0.43
$
0.40
$
0.46
$

All
Sizes
274.18
$
274.11
$
234.29
$
314.20
$
21.73
$
21.73
$
20.16
$
23.31
$

<
100
3.17
$
3.17
$
2.73
$
3.62
$
0.37
$
0.37
$
0.35
$
0.40
$

100­
499
5.04
$
5.04
$
4.25
$
5.81
$
0.55
$
0.55
$
0.51
$
0.60
$

500­
999
2.47
$
2.47
$
2.07
$
2.87
$
0.23
$
0.23
$
0.21
$
0.25
$

1,000­
3,299
1.61
$
1.61
$
1.32
$
1.90
$
0.10
$
0.10
$
0.09
$
0.11
$

3,300­
9,999
0.46
$
0.46
$
0.38
$
0.55
$
0.01
$
0.01
$
0.01
$
0.02
$

10,000­
49,999
0.10
$
0.10
$
0.09
$
0.11
$
0.01
$
0.01
$
0.01
$
0.01
$

50,000­
99,999
0.02
$
0.02
$
0.02
$
0.02
$
0.00
$
0.00
$
0.00
$
0.00
$

100,000­
999,999
0.03
$
0.03
$
0.03
$
0.03
$
0.00
$
0.00
$
0.00
$
0.00
$

1,000,000+
­
$
­
$
­
$
­
$
­
$
­
$
­
$
­
$

All
Sizes
12.90
$
12.90
$
10.87
$
14.91
$
1.29
$
1.29
$
1.18
$
1.39
$

287.08
$
287.01
$
245.16
$
329.11
$
23.02
$
23.02
$
21.34
$
24.70
$

839.51
$
842.98
$
546.68
$
1,108.57
$
56.86
$
56.23
$
41.86
$
74.94
$
System
Size
(
population
served)
Capital
Costs
CWSs
NTNCWSs
Subtotal
Subtotal
Median
Value
90
Percent
Confidence
Bound
Total
Ground
Water
Surface
Water
CWSs
NTNCWSs
O&
M
Costs
Mean
Value
Median
Value
90
Percent
Confidence
Bound
Source
Mean
Value
System
Classification
Table
VI.
D­
7.
Total
Initial
Capital
Costs
and
Steady­
State
O&
M
Costs
($
Millions/
Year).

Notes:
All
valuesEstimates
are
discounted
to
2003
and
given
in
2003
dollars.
Detail
may
not
add
to
totals
due
to
independent
rounding.
Source:
Exhibit
J.
1a,
USEPA
2005a.
211
c.
Monitoring
costs.
Because
systems
already
sample
for
the
Stage
1
DBPR,
costs
for
additional
routine
monitoring
are
determined
by
the
change
in
the
number
of
samples
to
be
collected
from
the
Stage
1
to
the
Stage
2
DBPR.
The
Stage
2
DBPR
monitoring
requirements
for
systems
are
based
only
on
population
served
and
source
water
type,
while
the
Stage
1
DBPR
requirements
are
also
based
on
the
number
of
treatment
plants.
With
this
modification
in
monitoring
scheme,
the
average
system
will
have
no
change
in
monitoring
costs.
The
number
of
samples
required
is
estimated
to
increase
for
some
systems
but
actually
decrease
from
the
Stage
1
to
the
Stage
2
DBPR
for
many
systems.
Table
VI.
D­
8
summarizes
the
estimated
additional
routine
monitoring
costs
for
systems.
212
Total
Additional
Compliance
Samples
per
Year
Total
Labor
Costs
Total
Sampling
Costs
Total
Costs
Total
Burden
(
Hours)
Total
Burden
(
FTEs)
A
B
C
D
E
F=
E/
2080
(
692)
7,844
$
(
166,169)
$
(
158,325)
$
348
0.17
(
3,571)
(
58,617)
$
(
857,050)
$
(
915,667)
$
(
2,369)
(
1.14)

3,594
91,070
$
862,541
$
953,611
$
3,594
1.73
(
10,496)
(
273,425)
$
(
2,204,194)
$
(
2,477,619)
$
(
10,496)
(
5.05)

1,452
40,671
$
305,021
$
345,692
$
1,452
0.70
609
19,041
$
127,915
$
146,956
$
609
0.29
128
3,996
$
26,846
$
30,843
$
128
0.06
24
735
$
4,939
$
5,674
$
24
0.01
National
Totals
(
8,953)
(
168,684)
$
(
1,900,150)
$
(
2,068,834)
$
(
6,711)
(
3.23)

793
26,209
$
190,302
$
216,511
$
1,173
0.56
5,777
143,617
$
1,386,523
$
1,530,140
$
5,777
2.78
552
14,385
$
115,964
$
130,349
$
552
0.27
(
277)
(
8,665)
$
(
58,213)
$
(
66,879)
$
(
277)
(
0.13)

(
209)
(
6,546)
$
(
43,976)
$
(
50,522)
$
(
209)
(
0.10)

National
Totals
6,636
169,000
$
1,590,600
$
1,759,600
$
7,015
3.37
0
0
$
0
$
0
$
0
0.00
0
0
$
0
$
0
$
0
0.00
96
2,433
$
23,040
$
25,473
$
96
0.05
0
0
$
0
$
0
$
0
0.00
16
500
$
3,360
$
3,860
$
16
0.01
­
­
$
­
$
­
$
0
0.00
­
­
$
­
$
­
$
0
0.00
­
­
$
­
$
­
$
0
0.00
National
Totals
112
2,933
$
26,400
$
29,333
$
112
0.05
1,241
27,552
$
297,860
$
325,412
$
1,241
0.60
1,393
34,481
$
334,297
$
368,779
$
1,393
0.67
63
1,633
$
13,163
$
14,796
$
63
0.03
9
270
$
1,815
$
2,085
$
9
0.00
­
­
$
­
$
­
$
0
0.00
National
Totals
2,705
63,936
$
647,135
$
711,072
$
2,705
1.30
Grand
Totals
500
67,185
$
363,986
$
431,171
$
3,122
1.50
 
5
 
Disinfecting
Ground
Water
Only
NTNCWSs
>
500,000
<
500
500­
9,999
10,000­
99,999
100,000­
499,999
10,000­
49,999
50,000­
249,999
250,000­
999,999
1,000,000­
4,999,999
Surface
Water
and
Mixed
NTNCWSs
<
500
500­
3,299
3,300­
9,999
500­
9,999
10,000­
99,999
100,000­
499,999
>
500,000
1,000,000­
4,999,999
 
5
 
Disinfecting
Ground
Water
Only
CWSs
<
500
3,300­
9,999
10,000­
49,999
50,000­
249,999
250,000­
999,999
Surface
Water
and
Mixed
CWSs
Size
Category
<
500
500­
3,299
Table
VI.
D­
8.
Total
Additional
Routine
Monitoring
Costs
for
Systems.

Notes:
(
A)
IncludesShows
the
difference
in
total
additional
(
or
fewer)
compliance
monitoring
samples
from
Stage
1
to
Stage
2
for
disinfecting
systems
and
systems
predicted
to
install
disinfection
for
the
GWR.
Source:
Exhibits
H.
8a
and
H.
8b,
USEPA
2005a.
213
Total
Hours
Average
Hours
per
State
Cost/
Labor
Hour
Total
Cost
Cost
per
State
A
B
=
A/
57
C
D
E
=
D/
57
Implementation
Activities
Public
Notification
11,856
208
33.60
$
398,362
$
6,989
$

Regulation
Adoption
and
Program
Development
59,280
1,040
33.60
$
1,991,808
$
34,944
$

Training
State
Staff
29,640
520
33.60
$
995,904
$
17,472
$

Training
PWS
Staff
and
Technical
Assistants
118,560
2,080
33.60
$
3,983,616
$
69,888
$

Updating
Data
Management
System
11,856
208
33.60
$
398,362
$
6,989
$

Subtotal
231,192
4,056
7,768,051
$
136,282
$

Monitoring
Plan
Activities
Monitoring
Plans
27,464
482
33.60
$
926,016
$
16,246
$

IDSE
Activities
IDSE
Monitoring
66,312
1,163
33.60
$
2,228,095
$
39,089
$

Additional
Routine
Monitoring
Activities
Recordkeeping
and
Compliance
Tracking
47,424
832
33.60
$
1,593,446
$
27,955
$

Operational
Evaluation
Costs
3,398
60
33.60
$
114,173
$
2,003
$

Subtotal
50,822
892
1,707,619
$
29,958
$

Grand
Total
375,790
6,593
12,629,781
$
221,575
$
3.
State/
Primacy
agency
costs
To
estimate
State/
Primacy
Agency
costs,
the
estimated
number
of
full­
time
equivalents
(
FTEs)
required
per
activity
is
multiplied
by
the
number
of
labor
hours
per
FTE,
the
State/
Primacy
Agency
hourly
wage,
and
the
number
of
States/
Primacy
Agencies.
EPA
estimated
the
number
of
FTEs
required
per
activity
based
on
experience
implementing
previous
rules,
such
as
the
Stage
1
DBPR.
State/
Primacy
Agency
costs
are
summarized
in
Table
VI.
D­
9.

Table
VI.
D­
9.
State/
Primacy
Agency
Cost
Summary.

Notes:
All
states/
primacy
agencies
are
assumed
to
incur
some
costs
for
each
activity.
Source:
Exhibits
H.
17
to
H.
20,
USEPA
2005a.

4.
Non­
quantified
costs
All
significant
costs
that
EPA
has
identified
have
been
quantified.
In
some
instances,
EPA
did
not
include
a
potential
cost
element
because
its
effects
are
relatively
minor
and
difficult
to
estimate.
For
example,
it
may
be
less
costly
for
a
small
system
to
merge
with
neighboring
systems
than
to
add
advanced
treatment.
Such
changes
have
both
costs
(
legal
fees
and
connecting
214
infrastructure)
and
benefits
(
economies
of
scale).
Likewise,
procuring
a
new
source
of
water
would
have
costs
for
new
infrastructure,
but
could
result
in
lower
treatment
costs.
Operational
costs
such
as
changing
storage
tank
operation
were
also
not
considered
as
alternatives
to
treatment.
These
might
be
options
for
systems
with
a
single
problem
area
with
a
long
residence
time.
In
the
absence
of
detailed
information
needed
to
evaluate
situations
such
as
these,
EPA
has
included
a
discussion
of
possible
effects
where
appropriate.
In
general,
however,
the
expected
net
effect
of
such
situations
is
lower
costs
to
PWSs.
Thus,
the
EA
tends
to
present
conservatively
high
estimates
of
costs
in
relation
to
non­
quantified
costs.

E.
Household
Costs
of
the
Stage
2
DBPR
EPA
estimates
that,
as
a
whole,
households
subject
to
the
Stage
2
DBPR
face
minimal
increases
in
their
annual
costs.
Approximately
86
percent
of
the
households
potentially
subject
to
the
rule
are
served
by
systems
serving
at
least
10,000
people;
these
systems
experience
the
lowest
increases
in
costs
due
to
significant
economies
of
scale.
Households
served
by
small
systems
that
add
treatment
will
face
the
greatest
increases
in
annual
costs.
Table
VI.
D­
9E­
1
summarizes
annual
household
cost
increases
for
all
system
sizes.
215
Total
Number
of
Households
Served
Mean
Annual
Household
Cost
Increase
Median
Annual
Household
Cost
Increase
90th
Percentile
Annual
Household
Cost
Increase
95th
Percentile
Annual
Household
Cost
Increase
Percentage
of
Annual
Household
Cost
Increase
<
$
12
Percentage
of
Annual
Household
Cost
Increase
<
$
120
All
Systems
101,553,868
0.62
$
0.03
$
0.36
$
0.98
$
99%
100%
All
Small
Systems
14,261,241
2.20
$
0.10
$
0.79
$
2.57
$
97%
100%
SW
<
10,000
3,251,893
4.58
$
0.79
$
2.69
$
7.24
$
95%
99%
SW
>
10,000
62,137,350
0.46
$
0.02
$
0.35
$
1.81
$
99%
100%
GW
<
10,000
11,009,348
1.49
$
0.02
$
0.39
$
0.99
$
98%
100%
GW
>
10,000
25,155,277
0.13
$
0.00
$
0.03
$
0.08
$
100%
100%

Total
Number
of
Households
Served
Mean
Annual
Household
Cost
Increase
Median
Annual
Household
Cost
Increase
90th
Percentile
Annual
Household
Cost
Increase
95th
Percentile
Annual
Household
Cost
Increase
Percentage
of
Household
Cost
Increase
<
$
12
Percentage
of
Household
Cost
Increase
<
$
120
All
Systems
10,161,304
5.53
$
0.80
$
10.04
$
22.40
$
92%
99%
All
Small
Systems
591,623
46.48
$
18.47
$
168.85
$
197.62
$
38%
89%
SW
<
10,000
285,911
43.05
$
13.79
$
173.53
$
177.93
$
47%
85%
SW
>
10,000
9,060,119
2.83
$
0.80
$
6.98
$
11.31
$
96%
100%
GW
<
10,000
305,712
49.69
$
16.65
$
109.86
$
197.62
$
31%
92%
GW
>
10,000
509,562
5.97
$
1.37
$
26.82
$
33.84
$
79%
100%
Households
Served
by
Plants
Adding
Treatment
Households
Served
by
All
Plants
Table
VI.
D­
9E­
1.
Annual
Household
Cost
Increases.

Notes:
Detail
may
not
add
to
total
due
to
independent
rounding.
Number
of
households
served
by
systems
adding
treatment
will
be
higher
than
households
served
by
plants
adding
treatment
because
an
entire
system
will
incur
costs
even
if
only
some
of
the
plants
for
that
system
add
treatment
(
this
would
result
in
lower
household
costs,
however).
Source:
Exhibit
7.15,
USEPA
2005a.

F.
Incremental
Costs
and
Benefits
of
the
Stage
2
DBPR
Incremental
costs
and
benefits
are
those
that
are
incurred
or
realized
in
reducing
DBP
exposures
from
one
alternative
to
the
next
more
stringent
alternative.
Estimates
of
incremental
costs
and
benefits
are
useful
in
considering
the
economic
efficiency
of
different
regulatory
options
considered
by
the
Agency.
Generally,
the
goal
of
an
incremental
analysis
is
to
identify
the
regulatory
option
where
net
social
benefits
are
maximized.
However,
the
usefulness
of
this
analysis
is
constrained
when
major
benefits
and/
or
costs
are
not
quantified
or
not
monetized.

Also,
as
pointed
out
by
the
Environmental
Economics
Advisory
Committee
of
the
Science
Advisory
Board,
efficiency
is
not
the
only
appropriate
criterion
for
social
decision
making
(
USEPA
2000ei).

For
the
proposed
Stage
2
DBPR,
presentation
of
incremental
quantitative
benefit
and
cost
216
comparisons
may
be
unrepresentative
of
the
true
net
benefits
of
the
rule
because
a
significant
portion
of
the
rule's
potential
benefits
are
not
quantified,
particularly
potential
reproductive
and
developmental
health
effects
(
see
Section
VI.
C)
and
the
cost­
effective
risk
targeting
strategy.

Table
VI.
F­
1
shows
the
incremental
monetized
costs
and
benefits
for
each
regulatory
alternative.

Evaluation
of
this
table
shows
that
incremental
costs
generally
fall
within
the
range
of
incremental
benefits
for
each
more
stringent
alternative.
Equally
important,
the
addition
of
any
benefits
attributable
to
the
non­
quantified
categories
would
add
to
the
benefits
without
any
increase
in
costs.

Table
VI.
F­
1
shows
that
the
Preferred
Alternative
is
the
least­
cost
alternative.
A
comparison
of
Alternative
1
with
the
Preferred
Alternative
shows
that
Alternative
1
would
have
approximately
the
same
benefits
as
the
Preferred
Alternative.
The
costs
of
Alternative
1
are
greater
due
to
the
additional
control
of
bromate.
However,
the
benefits
of
Alternative
1
are
less
than
the
Preferred
Alternative
because
the
Agency
is
not
able
to
estimate
the
additional
benefits
of
reducing
the
bromate
MCL.
Alternative
1
was
determined
to
be
unacceptable
due
to
the
potential
for
increased
risk
of
microbial
exposure.
Both
benefits
and
costs
are
greater
for
Alternative
2
and
Alternative
3
as
compared
to
the
Preferred
Alternative.
However,
these
regulatory
alternatives
do
not
have
the
risk­
targeted
design
of
the
Preferred
Alternative.
Rather,
implementation
of
these
stringent
standards
would
require
a
large
number
of
systems
to
change
treatment
technology.
The
high
costs
of
these
regulatory
alternatives
and
the
drastic
shift
in
the
nation's
drinking
water
practices
were
considered
unwarranted
at
this
time.
(
See
Section
VI.
A
of
this
preamble
for
a
description
of
regulatory
alternatives.)
217
Annual
Costs
Annual
Benefits
Incremental
Costs
Incremental
Benefits
Incremental
Net
Benefits
A
B
C
D
E=
D­
C
Preferred
79
$
1,531
$
79
$
1,531
$
1,452
$

Alternative
11
254
$
1,377
$
Alternative
2
422
$
5,167
$
343
$
3,637
$
3,294
$
Alternative
3
634
$
7,130
$
212
$
1,962
$
1,750
$
Preferred
79
$
763
$
79
$
763
$
684
$

Alternative
11
254
$
686
$
Alternative
2
422
$
2,575
$
343
$
1,812
$
1,469
$
Alternative
3
634
$
3,552
$
212
$
978
$
765
$

Preferred
77
$
1,246
$
77
$
1,246
$
1,170
$

Alternative
11
242
$
1,126
$
Alternative
2
406
$
4,227
$
330
$
2,981
$
2,651
$
Alternative
3
613
$
5,832
$
207
$
1,605
$
1,399
$
Preferred
77
$
621
$
77
$
621
$
544
$

Alternative
11
242
$
561
$
Alternative
2
406
$
2,105
$
330
$
1,484
$
1,154
$
Alternative
3
613
$
2,904
$
207
$
799
$
593
$
Footnote
1
Footnote
1
Footnote
1
Footnote
1
WTP
for
Non­
Fatal
Bladder
Cancer
Cases
Rule
Alternative
Lymphoma
Bronchitis
Bronchitis
Lymphoma
3
Percent
Discount
Rate
7
Percent
Discount
Rate
Table
VI.
F­
1.
Incremental
Costs
and
Benefits
of
the
Stage
2
DBPR.

Notes:
Estimates
are
discounted
to
2003
and
given
in
2003
dollars.
Based
on
TTHM
as
an
indicator,
Villanueva
et
al.
(
2003)
for
baseline
risk,
and
smoking/
lung
cancer
cessation
lag
model.
Assumes
26
percent
of
cases
are
fatal,
74
percent
are
non­
fatal
(
USEPA
1999b).
EPA
recognizes
that
benefits
may
be
as
low
as
zero
since
causality
has
not
yet
been
established
between
exposure
to
chlorinated
water
and
bladder
cancer.
Footnote
1:
Alternative
1
appears
to
have
fewer
benefits
than
the
Preferred
Alternative
because
it
does
not
incorporate
the
IDSE,
as
explained
in
Chapter
4.
Furthermore,
this
EA
does
not
quantify
the
benefits
of
reducing
the
MCL
for
bromate
(
and
potentially
associated
cancer
cases),
a
requirement
that
is
included
only
in
Alternative
1.
This
means
that
Alternative
1
is
dominated
by
the
Preferred
Alternative
in
this
analysis
(
having
higher
costs
than
the
Preferred
Alternative
but
lower
benefits),
and
so
it
is
not
included
in
the
incremental
comparison
of
alternatives
(
Columns
C
­
E).
OMB
states
this
in
terms
of
comparing
cost
effectiveness
ratios,
but
the
same
rule
applies
to
an
incremental
cost,
benefits,
or
net
benefits
comparison:
"
When
constructing
and
comparing
incremental
cost­
effectiveness
ratios,
[
analysts]
...
should
make
sure
that
inferior
alternatives
identified
by
the
principles
of
strong
and
weak
dominance
are
eliminated
from
consideration."
(
OMB
Circular
A­
4,
p.
10)
Source:
Exhibit
9.13,
USEPA
2005a.

G.
Benefits
From
the
Reduction
of
Co­
occurring
Contaminants
Installing
certain
advanced
technologies
to
control
DBPs
has
the
added
benefit
of
controlling
other
drinking
water
contaminants
in
addition
to
those
specifically
targeted
by
the
Stage
2
DBPR.
For
example,
membrane
technology
installed
to
reduce
DBP
precursors
can
also
reduce
or
eliminate
many
other
drinking
water
contaminants
(
depending
on
pore
size),
including
those
that
EPA
may
regulate
in
the
future.
Removal
of
any
contaminants
that
may
face
regulation
218
could
result
in
future
cost
savings
to
a
water
system.
Because
of
the
difficulties
in
establishing
which
systems
would
be
affected
by
other
current
or
future
rules,
no
estimate
was
made
of
the
potential
cost
savings
from
addressing
more
than
one
contaminant
simultaneously.

H.
Potential
Risks
From
Other
Contaminants
Along
with
the
reduction
in
DBPs
from
chlorination
such
as
TTHM
and
HAA5
as
a
result
of
the
Stage
2
DBPR,
there
may
be
increases
in
other
DBPs
as
systems
switch
from
chlorine
to
alternative
disinfectants.
For
all
disinfectants,
many
DBPs
are
not
regulated
and
many
others
have
not
yet
been
identified.
EPA
will
continue
to
review
new
studies
on
DBPs
and
their
occurrence
levels
to
determine
if
they
pose
possible
health
risks.
EPA
continues
to
support
regulation
of
TTHM
and
HAA5
as
indicators
for
chlorination
DBP
occurrence
and
believes
that
operational
and
treatment
changes
made
because
of
the
Stage
2
DBPR
will
result
in
an
overall
decrease
in
risk.

1.
Emerging
DBPs
Iodo­
DBPs
and
nitrogenous
DBPs
including
halonitromethanes
are
DBPs
that
have
been
recently
been
reported
(
Richardson
et
al.
2002,
Richardson
2003).
One
recent
occurrence
study
sampled
quarterly
at
twelve
surface
water
plants
using
different
disinfectants
across
the
U.
S.
for
several
iodo­
THMs
and
halonitromethane
species
(
Weinberg
et
al.
2002).
The
concentrations
of
iodo­
THMs
and
halonitromethane
in
the
majority
of
samples
in
this
study
were
less
than
the
analytical
minimum
reporting
levels;
plant­
average
concentrations
of
iodo­
THM
and
halonitromethane
species
were
typically
less
than
0.002
mg/
L,
which
is
an
order
of
magnitude
lower
than
the
corresponding
average
concentrations
of
TTHM
and
HAA5
at
those
same
plants.

Chloropicrin,
a
halonitromethane
species,
was
also
measured
in
the
ICR
with
a
median
concentration
of
0.00019
mg/
L
across
all
surface
water
samples.
No
occurrence
data
exist
for
the
219
iodoacids
due
to
the
lack
of
a
quantitative
method
and
standards.
Further
work
on
chemical
formation
of
iodo­
DBPs
and
halonitromethanes
is
needed.

Iodoacetic
acid
was
found
to
be
cytotoxic
and
genotoxic
in
Salmonella
and
mammalian
cells
(
Plewa
et
al.
2004a)
as
were
some
of
the
halonitromethanes
(
Kundu
et
al.
2004;
Plewa
et
al.

2004b).
Although
potent
in
these
in
vitro
screening
studies,
further
research
is
needed
to
determine
if
these
DBPs
are
active
in
living
systems.
No
conclusions
on
human
health
risk
can
be
drawn
from
such
preliminary
studies.

2.
N­
nitrosamines
Another
group
of
nitrogenous
DBPs
are
the
N­
nitrosamines.
A
number
of
N­
nitrosamines
exist,
and
N­
nitrosodimethylamine
(
NDMA),
a
probable
human
carcinogen
(
IRISUSEPA
1993),

has
been
identified
as
a
potential
health
risk
in
drinking
water.
NDMA
is
a
contaminant
from
industrial
sources
and
a
potential
disinfection
byproduct
from
reactions
of
chlorine
or
chloramine
with
nitrogen
containing
organic
matter
and
from
some
polymers
used
as
coagulant
aids.
Studies
have
produced
new
information
on
the
mechanism
of
formation
of
NDMA,
but
there
is
not
enough
information
at
this
time
to
draw
conclusions
regarding
a
potential
increase
in
NDMA
occurrence
as
systems
change
treatment.
Although
there
are
studies
that
examined
the
occurrence
of
NDMA
in
some
water
systems,
there
are
no
systematic
evaluations
of
the
occurrence
of
NDMA
and
other
nitrosamines
in
US
waters.
Recent
studies
have
provided
new
occurrence
information
that
shows
NDMA
forms
in
both
chlorinated
and
chloraminated
systems.

Barrett
et
al.
(
2003)
reported
median
concentrations
of
less
than
2ng/
L
for
the
seven
chlorine
systems
studied
and
less
than
3
ng/
L
for
13
chloramine
systems.
Another
study
demonstrated
that
factors
other
than
disinfectant
type
may
play
an
important
role
in
the
formation
of
NDMA
(
Schreiber
and
Mitch
2005).
More
research
is
underway
to
determine
the
extent
of
NDMA
occurrence
in
drinking
water
systems.
EPA
is
also
considering
proposinghas
proposed
220
monitoring
for
NDMA
under
Unregulated
Contaminant
Monitoring
Rule
2
(
70
FR
49094,
at
49103,
August
22,
2005)
(
USEPA
2005m).

Risk
assessments
have
estimated
that
the
10­
6
lifetime
cancer
risk
level
is
7
ng/
L
based
on
induction
of
tumors
at
multiple
sites.
NDMA
is
also
present
in
food,
tobacco
smoke,
and
industrial
emissions,
and
additional
research
is
underway
to
determine
the
relative
exposure
of
NDMA
in
drinking
water
to
these
other
sources.

3.
Other
DBPs
Some
systems,
depending
on
bromide
and
organic
precursor
levels
in
the
source
water
and
technology
selection,
may
experience
a
shift
to
higher
ratios,
or
concentrations,
of
brominated
DBPs
while
the
overall
TTHM
or
HAA5
concentration
may
decrease.
In
some
instances
where
alternative
disinfectants
are
used,
levels
of
chlorite
and
bromate
may
increase
as
a
result
of
systems
switching
to
chlorine
dioxide
or
ozone,
respectively.
However,
EPA
anticipates
that
changes
in
chlorite
and
bromate
concentration
as
a
result
of
the
Stage
2
DBPR
will
be
minimal
(
USEPA
2005a).
For
most
systems,
overall
levels
of
DBPs,
as
well
as
brominated
DBP
species,

should
decrease
as
a
result
of
this
rule.
EPA
continues
to
believe
that
precursor
removal
is
a
highly
effective
strategy
to
reduce
levels
of
DBPs.

EPA
also
considered
the
impact
this
rule
may
have
on
microbial
contamination
that
may
result
from
altering
disinfection
practices.
To
address
this
concern,
the
Agency
developed
this
rule
jointly
with
the
Long
Term
2
Enhanced
Surface
Water
Treatment
Rule
(
LT2ESWTR).
EPA
expects
that
the
LT2ESWTR
provisions
will
prevent
increases
in
microbial
risk
resulting
from
the
Stage
2
DBPR.

I.
Effects
of
the
Contaminant
on
the
General
Population
and
Groups
within
the
General
Population
that
are
Identified
as
Likely
to
be
at
Greater
Risk
of
Adverse
Health
Effects
221
EPA's
Office
of
Water
has
historically
considered
risks
to
sensitive
subpopulations
(
including
fetuses,
infants,
and
children)
when
establishing
drinking
water
assessments,
advisories
and
other
guidance,
and
standards
(
USEPA
1989)
(
56
FR
3526,
January
310,
1991)
(
USEPA
1991).
In
the
case
of
Stage
2
DBPR,
maximizing
health
protection
for
sensitive
subpopulations
requires
balancing
risks
to
achieve
the
recognized
benefits
of
controlling
waterborne
pathogens
while
minimizing
risk
of
potential
DBP
toxicity.
Experience
shows
that
waterborne
disease
from
pathogens
in
drinking
water
is
a
major
concern
for
children
and
other
subgroups
(
e.
g.,
the
elderly,

immunocompromised,
and
pregnant
women)
because
of
their
greater
vulnerabilities
(
Gerba
et
al.

1996).
EPA
believes
DBPs
may
also
potentially
pose
risks
to
fetuses
and
pregnant
women
(
USEPA
1998a).
In
addition,
because
the
elderly
population
(
age
65
and
above)
is
naturally
at
a
higher
risk
of
developing
bladder
cancer,
their
health
risks
may
further
increase
as
a
result
of
longterm
DBP
exposure
(
National
Cancer
Institute
2002).

In
developing
this
rule,
risks
to
sensitive
subpopulations,
including
children,
were
taken
into
account
in
the
assessments
of
disinfectants
and
DBPs.
More
details
on
sensitive
subpopulations
can
be
found
in
the
Economic
Analysis
for
today's
rule
(
USEPA
2005a).
For
each
of
the
DBPs
included
in
the
Stage
2
DBPR,
the
maximum
contaminant
level
goals
(
MCLG)

are
derived
using
the
most
sensitive
endpoint
among
all
available
data
and
an
intraspecies
uncertainty
factor
of
10
which
accounts
for
human
variability
including
sensitive
subpopulations,

like
children.
The
Agency
has
evaluated
several
alternative
regulatory
options
and
selected
the
one
that
balances
cost
with
significant
benefits,
including
those
for
sensitive
subpopulations.
The
Stage
2
DBPR
will
result
in
a
potential
reduction
in
cancer
risk
and
a
potential
reduction
in
reproductive
and
developmental
risk
to
fetuses
and
pregnant
women.
It
should
be
noted
that
the
LT2ESWTR,
which
accompanies
this
rule,
reduces
pathogens
in
drinking
water
and
further
protects
sensitive
subpopulations.
See
Section
VII.
G
for
a
discussion
of
EPA's
requirements
222
under
Executive
Order
13045.

J.
Uncertainties
in
the
Risk,
Benefit,
and
Cost
Estimates
for
the
Stage
2
DBPR
For
today's
final
rule,
EPA
has
estimated
the
current
baseline
risk
from
exposure
to
DBPs
in
drinking
water
and
projected
the
risk
reduction
and
cost
for
various
rule
alternatives.
There
is
uncertainty
in
the
risk
calculation,
the
benefit
estimates,
the
cost
estimates,
and
the
interaction
with
other
regulations.
The
Stage
2
DBPR
EA
has
an
extensive
discussion
of
relevant
uncertainties
(
USEPA
2005a).
This
section
briefly
summarizes
the
major
uncertainties.
Table
VI.
J­
1
presents
a
summary
of
uncertainty
in
the
cost
and
benefit
estimates,
refers
to
the
section
or
appendix
of
the
EA
where
the
information
is
introduced,
and
estimates
the
potential
effects
that
each
may
have
on
national
cost
and
benefit
estimates.

EPA
believes
that
uncertainty
in
the
compliance
forecast
has
a
potentially
large
influence
on
cost
and
benefit
estimates
for
today's
rule.
Thus,
the
Agency
has
attempted
to
quantify
the
uncertainty
by
giving
equal
weight
to
two
different
compliance
forecast
approaches.
One
compliance
forecast
approach
is
based
on
the
SWAT
predictions,
and
the
other
is
based
on
the
"
ICR
Matrix
Method."
The
ICR
Matrix
Method
uses
the
same
basic
approach
as
SWAT,
but
uses
TTHM
and
HAA5
data
from
the
ICR
directly
to
estimate
the
percent
of
plants
changing
technology
to
comply
with
the
Stage
2
DBPR
and
the
resulting
DBP
reduction.
To
characterize
the
uncertainty
of
the
compliance
forecast
results,
EPA
assumes
a
uniform
distribution
between
SWAT
and
ICR
Matrix
Method
results
(
USEPA
2005a).
That
is,
the
cost
and
benefit
estimates
presented
in
the
preamble
represent
the
midpoint
between
costs
and
benefits
estimated
using
the
SWAT
model,
and
those
estimated
using
the
ICR
Matrix
Method.
Cost
estimates
using
the
SWAT
model
are
about
25%
lower
than
the
midpoint
estimates,
while
those
using
the
ICR
Matrix
Method
are
about
25%
higher.
Benefits
estimated
using
the
SWAT
model
are
about
30%
lower
223
than
the
midpoint
estimates,
while
those
using
the
ICR
Matrix
Method
are
about
30%
higher.

EPA
believes
the
compliance
forecast
may
be
overstated
because
the
technology
decision
tree
does
not
consider
low­
cost,
non­
treatment
system
improvements
that
could
be
used
to
comply
with
the
Stage
2
DBPR.
These
improvements,
including
things
like
flushing
more
frequently
and
managing
storage
facilities
to
reduce
water
age,
could
be
used
by
systems
to
reduce
TTHM
and
HAA5
levels
for
specific
locations
in
their
distribution
system
to
meet
Stage
2
DBPR
MCLs.
Thus,
the
standard
compliance
forecast
method
as
developed
during
the
M/
DBP
FACA
(
with
a
20
percent
safety
margin)
is
a
reasonable
estimation.
However,
SWAT
does
not
explicitly
consider
the
IDSE.
To
address
uncertainty
in
the
impact
of
the
IDSE
on
the
compliance
forecast,
EPA
revised
the
compliance
forecast
methodology,
assigning
equal
probability
to
20
and
25
percent
operational
safety
margins.
EPA
believes
the
25
percent
safety
margin
is
a
reasonable
high­
end
estimate
of
system
response
to
account
for
the
influences
of
the
IDSE.
EPA
used
a
spatial
variability
analysis
to
determine
the
appropriate
safety
margin
to
use
to
estimate
the
impact
of
the
IDSE
on
the
compliance
forecast.

These
alternative
approaches
for
the
compliance
forecast
estimate
are
used
to
represent
a
range
of
possible
results
and
are
incorporated
into
the
cost
and
benefit
models
using
Monte
Carlo
probability
functions.
EPA
believes
this
approach
helps
inform
the
reader
of
the
likely
magnitude
of
the
impact
of
the
uncertainties.

In
addition
to
quantifying
some
uncertainties
in
the
compliance
forecasts,
EPA
has
explicitly
accounted
for
uncertainty
in
estimated
treatment
technology
costs.
Treatment
costs
are
modeled
using
a
triangular
distribution
of
±
30
percent
for
Capital,
and
±
15
percent
for
O&
M
costs
to
recognize
that
the
assumptions
for
cost
analysis
to
produce
the
national
average
are
uncertain
For
the
cost
estimates,
uncertainty
also
exists
in
baseline
data
inputs,
such
as
the
total
224
number
of
disinfecting
plants
and
their
typical
average
and
design
flow
rates.
Other
cost
model
inputs
such
as
labor
rates
and
laboratory
fees
also
contain
uncertainties.
In
these
cases,
EPA
has
evaluated
available
data
and
estimated
a
cost
input
value
to
represent
the
average
of
all
water
systems
nationally.
EPA
recognizes
that
there
is
uncertainty
in
this
average
and
variability
in
the
characteristics
of
individual
systems.
The
influence
of
these
uncertainties
on
national
cost
estimates
is
expected
to
be
fairly
minor.

For
the
benefits
estimates,
uncertainty
exists
in
model
inputs
such
as
the
estimated
PAR
values
and
the
cessation
lag
models.
EPA
considered
three
equally
valid
approaches
to
estimate
attributable
risk:
(
1)
a
range
of
risk
derived
from
individual
studies,
(
2)
a
risk
estimate
from
a
meta­
analysis,
and
(
3)
a
risk
estimate
from
a
pooled
analysis.
To
quantify
uncertainty
in
cessation
lag,
three
independent
cessation
lag
models
derived
from
three
different
epidemiological
studies
are
used.
Also,
two
functional
forms
are
used
for
each
of
these
data
sets
and
uncertainty
in
the
parameters
of
those
functions
is
included
in
the
analysis.
As
noted
previously,
causality
has
not
been
established
between
DBP
levels
and
cancer
endpoints,
so
the
lower
bound
of
potential
risk
reductions
may
be
as
low
as
zero.

In
a
number
of
different
contexts
over
the
past
few
years,
the
Agency
has
considered
the
relative
merits
and
assumptions
encountered
when
employing
meta­
analyses.
Cessation
lag
modeling
is
a
relatively
recent
analysis
that
the
Agency
has
incorporated
into
ourits
risk
analyses
to
more
closelyappropriately
model
the
actual
impactstiming
of
our
ruleshealth
benefits.
The
specific
papers
upon
which
the
Stage
2
analysis
is
based
have
been
peer
reviewed.
However,
the
Agency
believes
that
it
is
time
to
consider
these
Agency­
wide
science
issues
in
a
broader
sense
with
outside
experts
to
better
inform
the
Agency's
future
analyses.

For
monetization
of
benefits,
EPA
uses
two
alternatives
for
valuing
non­
fatal
bladder
cancer.
Other
uncertainties,
such
as
the
linear
relationship
between
DBP
reductions
and
225
reductions
in
bladder
cancer
cases
avoided,
are
discussed
qualitatively.

In
addition
to
the
uncertainties
quantified
as
part
of
the
benefits
evaluation,
other
uncertainties
that
have
not
been
quantified
could
result
in
either
an
over­
or
under­
estimation
of
the
benefits.
Two
of
the
greatest
uncertainties
affecting
the
benefits
of
the
Stage
2
DBPR,

benefits
from
potential
reductions
of
cancers
other
than
bladder
and
benefits
from
possible
reductions
in
potential
reproductive
and
developmental
health
effects,
are
unquantified.
Both
of
these
factors
could
result
in
an
underestimation
of
quantified
Stage
2
DBPR
benefits.
The
potential
magnitude
of
these
benefits
is
discussed
more
fully
in
the
EA.
226
Table
VI.
J­
1.
Effects
of
Uncertainties
on
National
Estimates.

Assumptions
for
Which
There
Is
Uncertainty
Section
with
Full
Discussion
of
Uncertainty
Potential
Effect
on
Benefit
Estimate
Potential
Effect
on
Cost
Estimates
Underestimate
Overestimate
Unknown
Impact
Underestimate
Overestimate
Unknown
Impact
Uncertainty
in
the
industry
baseline
(
SDWIS
and
1995
CWSS
data)
3.4
X
X
Uncertainty
in
observed
data
and
predictive
tools
used
to
characterize
DBP
occurrence
for
the
pre­
Stage
1
baseline
3.7
X
X
Uncertainty
in
predictive
tools
used
to
develop
the
compliance
forecast
for
surface
water
systems
(
SWAT
and
ICR
Matrix
Method)
Chapter
5,
Appendix
A
Quantified
in
primary
analysis
(
addresses
potential
underestimate
or
overestimate)
Quantified
in
primary
analysis
(
addresses
potential
underestimate
or
overestimate)

Uncertainty
in
ground
water
compliance
forecast
methodologies
Chapter
5,
A
and
B
X
X
Operational
safety
margin
of
20%
5.2
X
X
Impacts
of
the
IDSE
on
the
compliance
forecast
for
the
Preferred
Regulatory
Alternative
5.3
Quantified
in
the
primary
analysis
(
addresses
potential
underestimate)
Quantified
in
the
primary
analysis
(
addresses
potential
underestimate)

Uncertainty
in
the
PAR
value
6.1.1
Appendix
E
Quantified
in
the
primary
analysis
(
addresses
range
of
potential
underestimate
or
overestimateeffects,
but
true
values
could
lie
outside
range)

Reduction
in
TTHM
and
HAA5
used
as
proxies
for
all
chlorination
DBPs
6.3.3
X
DBPs
have
a
linear
nothreshold
dose­
response
relationship
for
bladder
cancer
effects
6.2.1
X
X
Uncertainty
in
benefits
valuation
inputs
6.5.2
Quantified
in
the
primary
analysis
(
addresses
potential
underestimate
or
overestimate)

Benefits
of
reduced
cancers
other
than
bladder
cancer
are
not
included
in
the
quantitative
analysis
6.7
Quantified
in
a
sensitivity
analysis
(
addresses
potential
underestimate)
Assumptions
for
Which
There
Is
Uncertainty
Section
with
Full
Discussion
of
Uncertainty
Potential
Effect
on
Benefit
Estimate
Potential
Effect
on
Cost
Estimates
Underestimate
Overestimate
Unknown
Impact
Underestimate
Overestimate
Unknown
Impact
227
Value
of
potential
reproductive
and
developmental
health
effects
avoided
is
not
quantified
in
the
primary
analysis
6.8
Quantifie
d
in
an
illustrativ
e
calculatio
n
(
address
es
potential
underesti
mate)
X
Treatment
costs
do
not
include
costs
for
minor
operational
changes
predicted
by
SWAT
7.4.1
X
Median
operational
and
water
quality
parameters
considered
for
technology
unit
costs
7.4.1
X
Economies
of
scale
for
combination
treatment
technologies
not
considered
7.4.1
X
Possible
UV­
chloramine
synergy
not
taken
into
account
7.4.1
X
Potential
low­
cost
alternatives
to
treatment
not
considered
7.4.2
X
Uncertainties
in
unit
costs
7.4.3
Quantified
in
primary
analysis
(
addresses
potential
overestimate
or
underestimate)

K.
Benefit/
Cost
Determination
for
the
Stage
2
DBPR
The
Agency
has
determined
that
the
benefits
of
the
Stage
2
DBPR
justify
the
costs.
As
discussed
previously,
the
main
concern
for
the
Agency
and
the
Advisory
Committee
involved
in
the
Stage
2
rulemaking
process
was
to
provide
more
equitable
protection
from
DBPs
across
the
entire
distribution
system
and
reduce
high
DBP
levels.
The
proposedfinal
rule
achieves
this
228
objective
using
the
least
cost
alternative
by
targeting
sampling
locations
with
high
DBP
levels
and
modifying
how
the
annual
average
DBP
level
is
calculated.
This
will
reduce
both
average
DBP
levels
associated
with
bladder
cancer
(
and
possibly
other
cancers)
and
peak
DBP
levels
which
are
potentially
associated
with
reproductive
and
developmental
effects.
In
addition,
this
rule
may
reduce
uncertainty
about
drinking
water
quality
and
may
allow
some
systems
to
avoid
installing
additional
technology
to
meet
future
drinking
water
regulations.

Table
VI.
K­
1
presents
net
benefits
for
the
four
regulatory
alternatives
evaluated
by
EPA.

This
table
shows
that
net
benefits
are
positive
for
all
four
regulatory
alternatives.
Generally,

analysis
of
net
benefits
is
used
to
identify
alternatives
where
benefits
exceed
costs,
as
well
as
the
alternative
that
maximizes
net
benefits.
However,
analyses
of
net
benefits
should
consider
both
quantified
and
non­
quantified
(
where
possible)
benefits
and
costs.
As
discussed
previously
with
incremental
net
benefits,
the
usefulness
of
this
analysis
in
evaluating
regulatory
alternatives
for
the
Stage
2
DBPR
is
somewhat
limited
because
many
benefits
from
this
rule
are
non­
quantified
and
non­
monetized.

Table
VI.
K­
1
shows
that
the
Preferred
Alternative
is
the
least
cost
alternative.
The
Preferred
Alternative
has
higher
mean
net
benefits
than
Alternative
1.
Alternatives
2
and
3
have
higher
benefits
than
the
Preferred
Alternative
but
also
much
greater
costs.
These
regulatory
alternatives
do
not
have
the
risk­
targeted
design
of
the
Preferred
Alternative.
Rather,
a
large
number
of
systems
would
be
required
to
make
treatment
technology
changes
to
meet
the
stringent
standards
under
these
regulatory
alternatives.
Also,
because
causality
has
not
been
established
between
DBP
exposure
and
bladder
cancer,
actual
benefits
may
be
as
low
as
zero.
EPA
is
promulgating
the
preferred
regulatory
alternative
because
the
Agency
believes
that
such
a
drastic
shift
in
the
nation's
drinking
water
practices
is
not
warranted
at
this
time.
229
230
Rule
Alternative
WTP
for
Non­
Fatal
Bladder
Cancer
Cases
Mean
Annual
Costs
Mean
Annual
Benefits
Mean
Net
Benefits
Preferred
78.8
$
1,530.8
$
1,452
$
A1
254.1
$
1,376.6
$
1,122
$
A2
421.7
$
5,167.4
$
4,746
$
A3
634.2
$
7,129.6
$
6,495
$

Preferred
78.8
$
762.8
$
$
684
A1
254.1
$
685.9
$
432
$
A2
421.7
$
2,574.6
$
2,153
$
A3
634.2
$
3,552.2
$
2,918
$

Preferred
76.8
$
1,246.5
$
1,170
$
A1
241.8
$
1,126.4
$
885
$
A2
406.4
$
4,227.2
$
3,821
$
A3
613.1
$
5,832.4
$
5,219
$

Preferred
76.8
$
620.7
$
$
544
A1
241.8
$
560.8
$
319
$
A2
406.4
$
2,104.6
$
1,698
$
A3
613.1
$
2,903.8
$
2,291
$
Lymphoma
Bronchitis
7
Percent
Discount
Rate,
25
Years
3
Percent
Discount
Rate,
25
Years
Lymphoma
Bronchitis
Table
VI.
K­
1.
Mean
Net
Benefits
by
Regulatory
Alternative
($
Million).

Notes:
Estimates
are
discounted
to
2003
and
given
in
2003
dollars.
Based
on
TTHM
as
an
indicator,
Villanueva
et
al.
(
2003)
for
baseline
risk,
and
smoking/
lung
cancer
cessation
lag
model.
Assumes
26
percent
of
cases
are
fatal,
74
percent
are
non­
fatal
(
USEPA
1999b).
EPA
recognizes
that
benefits
may
be
as
low
as
zero
since
causality
has
not
yet
been
established
between
exposure
to
chlorinated
water
and
bladder
cancer.
Source:
Exhibits
9.10
and
9.11,
USEPA
2005a.

The
Agency
also
compared
the
costs
and
benefits
for
each
regulatory
alternative
by
calculating
which
option
is
the
most
cost­
effective.
The
cost­
effectiveness
analysis
compares
the
cost
of
the
rule
per
bladder
cancer
case
avoided.
This
cost­
effectiveness
measure
is
another
way
of
examining
the
benefits
and
costs
of
the
rule,
but
should
not
be
used
to
compare
alternatives
because
an
alternative
with
the
lowest
cost
per
illness/
death
avoided
may
not
result
in
the
highest
net
benefits.
Table
VI.
K­
2
shows
the
cost
of
the
rule
per
case
avoided.
This
table
shows
that
cost
per
case
avoided
for
the
preferred
alternative
seems
favorable
when
compared
to
the
willingness
to
pay
estimates.
Additional
information
about
this
analysis
and
other
methods
of
comparing
benefits
and
costs
can
be
found
in
the
EA
(
USEPA
2005a).
231
Table
VI.
K­
2.
Estimated
Cost
Per
Discounted
Case
Avoided1
for
the
Regulatory
Alternatives,
using
TTHM
as
DBP
Indicator
and
Smoking/
Lung
Cancer
Cessation
Lag
Model
($
Millions,
2003$).

Rule
Alternative
Cost
Per
Case
Avoided
3%
7%
Preferred
$
0.363
$
0.451
Alternative
1
$
1.3018
$
1.5742
Alternative
2
$
0.562
$
0.683
Alternative
3
$
0.6157
$
0.7469
Notes:
1
The
cost
effectiveness
ratios
are
a
potentially
a
high
estimate
because
regulatory
costs
in
the
numerator
are
not
adjusted
by
subtracting
the
avoided
medical
costs
associated
with
cases
avoided
to
produce
a
net
cost
numerator.
Subtraction
of
theses
costs
would
not
be
expected
to
alter
the
ranking
of
alternatives.
In
the
case
where
thresholds
of
maximum
public
expenditure
per
case
avoided
are
prescribed,
defining
the
numerator
more
precisely
by
making
such
adjustments
would
be
appropriate.
Notes:
In
reference
to
conducting
incremental
CEA,
OMB
states
that
the
analyst
should
make
sure
that
"
When
constructing
and
comparing
incremental
cost­
effectiveness
ratios,
[
analysts]
...
should
make
sure
that
inferior
alternatives
identified
by
the
principles
of
strong
and
weak
dominance
are
eliminated
from
consideration"
(
OMB
Circular
A­
4,
p.
10).
Alternative
1
is
dominated
by
the
Preferred
Alternative
and
is
therefore
not
included
in
the
incremental
analysis.
The
reason
for
this
domination
is
mainly
that
the
Preferred
Alternative
includes
IDSE
and
Alternative
1
does
not;
and
to
a
lesser
degree
because
the
bromate
control
included
in
Alternative
1
increases
the
costs
but
the
benefits
of
this
control
are
not
quantified
at
this
time.
Alternative
2
is
compared
directly
to
the
Preferred
Alternative
(
skipping
Alternative
1)
in
this
analysis.
Cost
per
case
avoided
is
in
year
2003
dollars
($
Millions),
discounted
for
the
25
year
analysis
period
to
year
2005.
1The
cost
effectiveness
ratios
are
a
conservative
estimate
in
that
the
regulatory
costs
in
the
numerator
are
not
adjusted
by
subtracting
the
medical
costs
associated
with
cases
avoided
to
produce
a
net
cost
numerator.
Adjustment
of
the
numerator
in
this
CEA
would
not
alter
the
relative
cost
effectiveness
of
the
alternatives
or
change
their
rankings
because
it
involves
the
subtraction
of
a
constant.
In
the
case
where
thresholds
of
maximum
public
expenditure
or
minimum
cases
to
be
avoided
are
prescribed,
defining
the
numerator
more
precisely
by
making
such
adjustments
would
be
appropriate.
Source:
Exhibit
9.14,
USEPA,
2005a.

L.
Summary
of
Major
Comments
EPA
received
significant
public
comment
on
the
analysis
of
benefits
and
costs
of
the
proposed
Stage
2
DBPR
in
the
following
areas:
interpretation
of
health
effects
studies,
derivation
of
benefits,
use
of
SWAT,
illustrative
example,
unanticipated
risk
issues,
and
valuation
of
cancer
cases
avoided.
The
following
discussion
summarizes
public
comment
in
these
areas
and
EPA's
responses.

1.
Interpretation
of
health
effects
studies
232
EPA
requested
comment
on
the
conclusions
of
the
cancer
health
effects
section
and
the
epidemiology
and
toxicology
studies
discussed.
A
number
of
comments
questioned
the
overall
interpretation
of
the
studies
presented
by
EPA.
A
few
comments
pointed
out
missed
studies.

Commenters
also
asked
about
concordance
between
cancer
epidemiology
and
toxicology.
Some
commenters
also
felt
EPA
did
not
discuss
the
broad
range
of
risks
from
DBPs
other
than
the
ones
regulated.

The
Agency
continues
to
believe
that,
although
there
is
not
a
causal
link,
the
cancer
literature
points
to
an
association
between
bladder
cancer
and
potentially
rectal
and
colon
cancer
and
exposure
to
chlorinated
surface
water.
EPA
has
included
in
today's
preamble
the
literature
that
commenters
pointed
out
as
missing
and
expands
on
its
discussion
of
non­
regulated
DBPs.

EPA
believes
that
a
lack
of
bladder
cancer
effect
in
toxicological
studies
does
not
negate
the
findings
in
epidemiological
studies
at
this
time.
Tumor
site
concordance
between
human
and
test
animal
is
not
necessary
to
determine
carcinogenic
potential.
While
there
is
evidence
from
human
cancer
epidemiology
studies
that
lifetime
consumption
of
the
DBP
mixture
within
chlorinated
surface
water
poses
a
bladder
cancer
risk,
the
specific
causative
constituents
have
not
been
identified.
EPA
will
continue
to
evaluate
new
mode­
of­
action
data
as
it
becomes
available.

Several
comments
were
received
on
EPA's
characterization
of
the
literature
on
reproductive
and
developmental
health
risk.
Some
commenters
wanted
EPA
to
characterize
reproductive
and
developmental
health
effects
more
strongly,
stating
that
current
research
shows
more
evidence
for
these
effects
than
described
in
the
proposed
preamble.
Others
thought
that
EPA's
characterization
in
the
proposal
was
too
strong,
and
that
EPA
had
overemphasized
these
health
concerns.
Some
commenters
noted
that
certain
published
studies
were
missing
from
EPA's
risk
discussion.

EPA
believes
that
the
characterization
of
reproductive
and
developmental
risks
in
the
final
233
Stage
2
DBPR
preamble
is
appropriate
based
on
the
weight
of
evidence
evaluation
of
the
reproductive
and
developmental
epidemiology
database
described
in
Section
III.
C.
EPA
considered
comments
and
incorporated
additional
and
recent
studies
into
its
characterization
of
health
risks
in
today's
final
preamble.
While
no
causal
link
has
been
established,
EPA's
evaluation
of
the
available
studies
continues
to
indicate
a
potential
health
hazard
that
warrants
additional
regulatory
action
beyond
the
Stage
1
DBPR.
The
inconsistencies
and
uncertainties
remaining
in
the
available
science
support
the
incremental
nature
of
change
in
today's
rule.

EPA
did
not
include
all
findings
from
every
study
in
the
proposed
DBPR
preamble
because
the
intent
was
to
provide
a
summary
overview
and
more
importantly,
the
Agency's
conclusions
regarding
the
weight
of
evidence.
Positive
associations,
especially
statistically
significant
ones,
should
be
given
due
notice.
Negative
findings
are
also
important,
but
they
can
only
indicate
that
no
association
was
found,
not
provide
evidence
that
an
association
does
not
exist.
Because
of
this,
EPA
mentioned
negative
findings
but
did
not
focus
on
them.
The
epidemiology
literature
has
inconsistencies
in
its
findings
on
the
relationship
between
various
reproductive
and
developmental
health
effects
and
DBPs.
In
this
final
preamble,
EPA
describes
how
recent
studies
since
the
proposal
further
inform
the
perspective
of
overall
risk
from
exposure
to
DBPs.
EPA
continues
to
believe
that
studies
indicate
a
potential
hazard.

2.
Derivation
of
benefits
EPA
received
numerous
comments
on
the
derivation
of
benefits
from
occurrence
estimates
for
the
Stage
2
DBPR.
The
majority
of
the
comments
provided
addressed
EPA's
use
of
a
cessation
lag
model
to
estimate
the
timing
of
benefits
and
a
PAR
analysis
to
estimate
reduced
risks.
Several
commenters
opposed
the
cessation
lag
model
proposed
by
EPA,
suggesting
that
EPA
use
a
longer
cessation
lag
period
or
conduct
a
sensitivity
analysis
on
the
cessation
lag
exponent.
234
In
the
effort
to
develop
a
cessation
lag
model
specific
to
DBPs,
EPA
reviewed
the
available
epidemiological
literature
for
information
relating
to
the
timing
of
exposure
and
response,
but
could
not
identify
any
studies
that
could,
alone
or
in
combination,
support
a
specific
cessation
lag
model
for
DBPs
in
drinking
water.
Thus,
in
keeping
with
the
SAB
recommendation
to
consider
other
models
in
the
absence
of
specific
cessation
lag
information
(
USEPA
2001cd),

EPA
explored
the
use
of
information
on
other
carcinogens
that
could
be
used
to
characterize
the
influence
of
cessation
lag
in
calculating
benefits.
The
benefit
analysis
for
today's
rule
uses
three
cessation
lag
models,
which
allows
for
a
better
characterization
of
uncertainty
than
did
the
approach
used
in
the
proposal.
More
details
on
this
analysis
are
in
the
EA
published
with
today's
rule
(
USEPA
2005a).

Additional
comments
were
received
on
the
use
of
PAR
values
derived
from
epidemiology
studies
to
determine
the
number
of
bladder
cancer
cases
attributable
to
DBP
exposure.
Some
commenters
remarked
that
there
was
not
sufficient
evidence
in
the
epidemiology
studies
used
to
develop
a
reliable
PAR
estimate.
A
key
issue
expressed
in
the
comments
was
that
studies
that
developed
the
PAR
estimates
did
not
adequately
control
for
confounders.
One
commenter
supported
EPA
review
of
the
Villanueva
(
2003)
meta­
analysis,
stating
that
this
was
the
best
available
data
on
the
issue.

EPA
revised
the
methodology
for
calculating
PAR
values
for
bladder
cancer
associated
with
exposure
to
chlorinated
drinking
water
by
considering
three
different
analytical
approaches
as
described
in
Section
V.
B.
2.
EPA
used
the
PAR
values
from
all
three
approaches
to
estimate
the
number
of
bladder
cancer
cases
ultimately
avoided
annually
as
a
result
foof
the
Stage
2
DBPR.

AllTaken
together,
the
three
approaches
are
equally
valid
and
give
feasibleprovide
a
reasonable
estimates
of
the
range
of
potential
risk.
For
simplicity,
EPA
used
the
Villanueva
et
al.
(
2003)

study
to
calculate
the
annual
benefits
of
the
rule.
The
benefit
estimates
derived
from
Villanueva
et
235
al.
(
2003)
capture
a
substantial
portion
of
the
overall
range
of
results,
reflecting
the
uncertainty
in
both
the
underlying
OR
and
PAR
values,
as
well
as
the
uncertainty
in
DBP
reductions
for
Stage
2.

More
details
on
the
PAR
analysis
can
be
found
in
the
EA
that
accompanies
today's
final
rule
(
USEPA
2005a).

3.
Use
of
SWAT
Comments
received
on
the
use
of
SWAT
for
the
compliance
forecast
claimed
that
the
model
probably
underestimates
DBP
occurrence
levels
and
hence
underestimates
compliance
costs.
Other
commenters
supported
EPA's
occurrence
estimation
methods
and
results.
Some
commenters
added
that
monitoring
under
the
IDSE
will
produce
different
results
than
monitoring
for
the
ICR
and
that
SWAT
did
not
capture
these
changes.

EPA
describes
in
detail
the
limitations
of
SWAT
as
well
as
all
assumptions
and
uncertainties
associated
with
the
model
in
the
EA
published
with
today's
rule.
EPA
believes
that,

for
the
reasons
stated
below,
the
standard
compliance
forecast
method
using
SWAT,
as
developed
during
the
M­
DBP
FACA,
provides
a
reasonable
prediction
of
national
treatment
changes
and
resulting
DBP
levels
anticipated
for
the
Stage
2
DBPR:

1.
SWAT
predictive
equations
for
TTHM
and
HAA5
were
calibrated
to
ICR­
observed
TTHM
and
HAA5
data.

2.
SWAT
estimates
are
based
on
12
months
of
influent
water
quality
data,
treatment
train
information,
and
related
characteristics
for
the
273
ICR
surface
water
plants.
EPA
believes
thise
ICR
data
provides
a
robust
basis
for
the
compliance
forecast
as
it
represents
significant
variability
with
respect
to
factors
influencing
DBP
formation,
including
temperature,
residence
time,
and
geographical
region.

3.
EPA
uses
a
"
delta"
approach
to
reduce
the
impact
of
uncertainty
in
SWAT's
predictive
equations
for
TTHM
and
HAA5.
Under
this
approach,
EPA
compared
SWAT­
predicted
236
results
for
pre­
Stage
1
data
to
modeled
pre­
Stage
21)
estimates
the
difference
in
technology
and
TTHM
and
HAA5
concentration
predictions
between
pre­
Stage
1
and
post­
Stage
1;
2)
estimates
the
difference
in
technology
and
TTHM
and
HAA5
concentration
predictions
between
pre­
Stage
1
and
post­
Stage
2
data,
which
reduces
potential
inconsistencies
in
comparing
observed
and
predicted
data
and
reduces
potential
errors
in
technology
selection
and
TTHM/
HAA5
occurrence
resulting
from
SWAT.
;
and
3)
subtracts
the
result
of
the
first
estimate
from
the
second
estimate
to
predict
the
impacts
between
Stage
1
and
Stage
2.
Since
each
predictive
estimate
has
bias
in
the
same
direction,
EPA
believes
that
this
methodology
minimized
overall
predictive
error.

In
response
to
commenters
concerns
about
potential
uncertainties
in
the
SWAT
predictions,
EPA
also
developed
the
"
ICR
Matrix
method."
The
ICR
Matrix
Method
uses
TTHM
and
HAA5
data
from
the
ICR
to
estimate
the
percent
of
plants
changing
technology
to
comply
with
the
Stage
2
DBPR
and
the
resulting
DBP
reduction.
The
EA
includes
a
detailed
description
of
the
ICR
Matrix
Method
(
USEPA
2005a).
In
the
analysis
for
today's
rule,
EPA
gives
equal
weight
to
SWAT
and
ICR
Matrix
Method
predictions
in
estimating
Stage
2
compliance
forecasts
and
resultant
reductions
in
DBP
exposure.
The
ICR
Matrix
Method
is
also
used
to
estimate
reductions
in
the
occurrence
of
peak
TTHM
and
HAA5
concentrations
because
SWAT­
predicted
TTHM
and
HAA5
concentrations
are
valid
only
when
considering
national
averages,
not
at
the
plant
level.

EPA
revised
the
Stage
2
DBPR
compliance
forecast
methodology
to
quantify
the
potential
impacts
of
the
IDSE
for
large
and
medium
surface
water
systems.
For
these
systems,
EPA
predicted
compliance
implications
using
a
safety
margin
of
both
20
and
25
percent
based
on
an
analysis
of
spatial
variability
in
TTHM
and
HAA5
occurrence.
EPA
assigned
equal
probability
to
the
20
and
25
percent
safety
margins
because
both
alternatives
are
considered
equally
plausible.
237
These
changes
result
in
a
wider
uncertainty
range
for
the
compliance
cost
estimates
than
under
the
EA
of
the
proposed
rule.
EPA
assumes
the
20
percent
operational
safety
margin
accounts
for
variability
in
small
surface
water
systems
and
all
ground
water
systems.
Small
systems
are
not
expected
to
find
significantly
higher
levels
that
affect
their
compliance
as
a
result
of
the
IDSE
because
their
distribution
systems
are
not
as
complex
as
large
systems.
Additionally,
the
IDSE
is
not
expected
to
significantly
impact
the
compliance
forecast
for
ground
water
systems
because
they
have
more
consistent
source
water
quality
and
do
not
experience
significant
year­
to­
year
variability
in
TTHM
and
HAA5
occurrence.

As
some
commenters
noted,
any
underestimation
in
costs
as
a
result
of
the
compliance
forecast
is
associated
with
an
underestimation
in
the
benefits.
However,
EPA
believes
that
the
current
estimates
of
costs
and
benefits
and
the
uncertainty
analysis
capture
the
overall
net
change
in
potential
risks
and
benefits
due
to
the
rule.
Accordingly,
EPA
adjusted
both
cost
and
benefits
estimates
based
on
the
ICR
Matrix
Method
and
the
impact
of
the
IDSE
for
the
upper
end
of
the
compliance
forecast
range.

4.
Illustrative
example
Many
comments
were
received
on
the
illustrative
calculation
of
fetal
loss
benefits
included
in
the
proposed
EA.
Many
commenters
recommended
that
EPA
remove
this
calculation
because
of
uncertainties
in
the
underlying
data.
Other
commenters,
however,
expressed
support
for
this
calculation
because
of
the
magnitude
of
thepotential
benefits
received,
and
suggested
that
EPA
fully
quantifyinclude
these
benefits
in
its
primary
analysis.

EPA
believes
that
the
reproductive
and
developmental
epidemiologic
data,
although
not
conclusive,
are
suggestive
of
potential
health
effects
in
humans
exposed
to
DBPs.
EPA
does
not
believe
the
available
evidence
provides
an
adequate
basis
for
quantifying
potential
reproductive
and
developmental
risks.
Nevertheless,
given
the
widespread
nature
of
exposure
to
DBPs,
the
238
importance
our
society
places
on
reproductive
and
developmental
health,
and
the
large
number
of
fetal
losses
experienced
each
year
in
the
US
(
nearly
1
million),
the
Agency
believes
that
it
is
importantappropriate
to
provide
some
quantitative
indication
of
the
potential
risk
suggested
by
some
of
the
published
results
on
reproductive
and
developmental
endpoints,
despite
the
absence
of
certainty
regarding
a
causal
link
between
disinfection
byproducts
and
these
risks
and
the
inconsistencies
between
studies.
However,
the
Agency
is
unable
at
this
time
to
either
develop
a
specific
estimate
of
the
value
of
avoiding
fetal
loss
or
to
use
a
benefit
transfer
methodology
to
estimate
the
value
from
studies
that
address
other
endpoints.

5.
Unanticipated
risk
issues
Comments
were
received
that
expressed
concern
about
unanticipated
risks
that
could
result
from
the
proposed
Stage
2
DBPR.
Several
commenters
remarked
that
regulation
of
TTHM
and
HAA5
would
not
control
levels
of
other
DBPs
that
may
be
more
toxic
than
these
indicator
compounds,
such
as
NDMA.
Some
commenters
supported
future
research
on
the
potential
health
effects
of
other
DBPs.
Other
comments
suggested
that
EPA
further
consider
these
risks
when
developing
the
final
Stage
2
DBPR.

EPA
has
addressed
the
occurrence
of
other
DBPs
in
Section
VI.
H
of
this
document
and
in
the
EA
(
USEPA
2005a).
Levels
of
some
DBPs
may
increase
because
of
treatment
changes
anticipated
as
a
result
of
today's
rule.
However,
these
DBPs
generally
occur
at
much
lower
levels
than
TTHM
and
HAA5,
often
more
than
an
order
of
magnitude
less
(
USEPA
2005f,
Weinberg
et
al.
2002).
For
NDMA,
studies
have
shown
formation
in
both
chlorinated
and
chloraminated
systems
(
Barrett
et
al.
2003
2003).
The
uncertainties
surrounding
NDMA
formation
make
determinations
regarding
the
impact
of
the
Stage
2
DBPR
difficult.
In
addition,
other
routes
of
exposure
appear
to
be
more
significant
than
drinking
water.
Dietary
sources
of
NDMA
include
preserved
meat
and
fish
products,
beer
and
tobacco.
EPA
is
looking
at
calculating
the
relative
239
source
contribution
of
these
routes
of
exposure
compared
to
drinking
water.

EPA
continues
to
support
the
use
of
TTHM
and
HAA5
as
indicators
for
DBP
regulation.

The
presence
of
TTHM
and
HAA5
is
representative
of
the
occurrence
of
many
other
chlorination
DBPs;
thus,
a
reduction
in
the
TTHM
and
HAA5
generally
indicates
an
overall
reduction
of
DBPs.
EPA
also
supports
additional
research
on
unregulated
and
unknown
DBPs
to
ensure
continual
public
health
protection.

6.
Valuation
of
cancer
cases
avoided
A
number
of
commenters
remarked
on
the
valuation
of
cancer
cases
avoided.
Some
commenters
supported
the
use
of
value
of
statistical
life
(
VSL)
analysis
in
monetizing
the
benefits
of
fatal
bladder
cancer
cases
avoided.
Comments
were
also
received
in
support
of
the
addition
of
expected
medical
costs
for
treating
fatal
bladder
cancer
cases
to
the
VSL
estimates.
Other
commenters
recommended
that
EPA
further
review
the
use
of
willingness­
to­
pay
estimates
used
to
value
the
non­
fatal
cancer
cases
avoided.
These
comments
stated
concern
over
the
similarity
of
bronchitis
and
lymphoma
to
bladder
cancer
and
the
resulting
limitation
of
benefits
transfer.

EPA
thanks
commenters
for
expressing
support
of
the
use
of
VSL
and
valuation
of
fatal
bladder
cancer
cases.
EPA
acknowledges
that
the
willingness
to
pay
(
WTP)
to
avoid
curable
lymphoma
or
chronic
bronchitis
is
not
a
perfect
substitute
for
the
WTP
to
avoid
a
case
of
nonfatal
bladder
cancer.
However,
non­
fatal
internal
cancers,
regardless
of
type,
generally
present
patients
with
very
similar
treatment,
health,
and
long­
term
quality
of
life
implications,
including
surgery,
radiation
or
chemotherapy
treatments
(
with
attendant
side
effects),
and
generally
diminished
vitality
over
the
duration
of
the
illness.
In
the
absence
of
more
specific
WTP
studies,

EPA
believes
the
WTP
values
for
avoiding
a
case
of
curable
lymphoma
or
a
case
of
chronic
bronchitis
provides
a
reasonable,
though
not
definitive,
substitute
for
the
value
of
avoiding
nonfatal
bladder
cancer.
240
VII.
Statutory
and
Executive
Order
Reviews
A.
Executive
Order
12866:
Regulatory
Planning
and
Review
Under
Executive
Order
12866,
[
58
FR
51735,
(
October
4,
1993)]
the
Agency
must
determine
whether
the
regulatory
action
is
"
significant"
and
therefore
subject
to
OMB
review
and
the
requirements
of
the
Executive
Order.
The
Order
defines
"
significant
regulatory
action"
as
one
that
is
likely
to
result
in
a
rule
that
may:

(
1)
have
an
annual
effect
on
the
economy
of
$
100
million
or
more
or
adversely
affect
in
a
material
way
the
economy,
a
sector
of
the
economy,
productivity,
competition,
jobs,
the
environment,

public
health
or
safety,
or
State,
local,
or
Tribal
governments
or
communities;

(
2)
create
a
serious
inconsistency
or
otherwise
interfere
with
an
action
taken
or
planned
by
another
agency;

(
3)
materially
alter
the
budgetary
impact
of
entitlements,
grants,
user
fees,
or
loan
programs
or
the
rights
and
obligations
of
recipients
thereof;
or
(
4)
raise
novel
legal
or
policy
issues
arising
out
of
legal
mandates,
the
President's
priorities,
or
the
principles
set
forth
in
the
Executive
Order.

Pursuant
to
the
terms
of
Executive
Order
12866,
it
has
been
determined
that
this
rule
is
a
"
significant
regulatory
action."
As
such,
this
action
was
submitted
to
OMB
for
review.
Changes
made
in
response
to
OMB
suggestions
or
recommendations
will
be
documented
in
the
public
record.

B.
Paperwork
Reduction
Act
The
Office
of
Management
and
Budget
(
OMB)
has
approved
the
information
collection
requirements
contained
in
this
rule
under
the
provisions
of
the
Paperwork
Reduction
Act,
44
241
U.
S.
C.
3501
et
seq.
and
has
assigned
OMB
control
number
2040­
XXXX2040­
0265
(
USEPA
2005n).

The
information
collected
as
a
result
of
this
rule
will
allow
the
States
and
EPA
to
determine
appropriate
requirements
for
specific
systems,
and
to
evaluate
compliance
with
the
rule.

For
the
first
three
years
after
Stage
2
DBPR
promulgation,
the
major
information
requirements
involve
monitoring
activities,
which
include
conducting
the
IDSE
and
submission
of
the
IDSE
report,
and
tracking
compliance.
The
information
collection
requirements
are
mandatory
(
Part
141),
and
the
information
collected
is
not
confidential.

The
estimate
of
annual
average
burden
hours
for
the
Stage
2
DBPR
for
systems
and
States
is
2228,57629
hours.
This
estimate
covers
the
first
three
years
of
the
Stage
2
DBPR
and
most
of
the
IDSE
(
small
system
reports
are
not
due
until
the
fourth
year).
The
annual
average
aggregate
cost
estimate
is
$
9.18
million
for
operation
and
maintenance
as
a
purchase
of
service
for
lab
work
and
$
6.46
million
is
associated
with
labor.
The
annual
burden
hour
per
response
is
4.3518
hours.

The
frequency
of
response
(
average
responses
per
respondent)
is
67.8359
annually.
The
estimated
number
of
likely
respondents
is
7,497202
per
year
(
the
product
of
burden
hours
per
response,
frequency,
and
respondents
does
not
total
the
annual
average
burden
hours
due
to
rounding).
Because
disinfecting
systems
have
already
purchased
basic
monitoring
equipment
to
comply
with
the
Stage
1
DBPR,
EPA
assumes
no
capital
start­
up
costs
are
associated
with
the
Stage
2
DBPR
ICR.

Burden
means
the
total
time,
effort,
or
financial
resources
expended
by
persons
to
generate,
maintain,
retain,
or
disclose
or
provide
information
to
or
for
a
Federal
agency.
This
includes
the
time
needed
to
review
instructions;
develop,
acquire,
install,
and
utilize
technology
and
systems
for
the
purposes
of
collecting,
validating,
and
verifying
information,
processing
and
maintaining
information,
and
disclosing
and
providing
information;
adjust
the
existing
ways
to
242
comply
with
any
previously
applicable
instructions
and
requirements;
train
personnel
to
be
able
to
respond
to
a
collection
of
information;
search
data
sources;
complete
and
review
the
collection
of
information;
and
transmit
or
otherwise
disclose
the
information.

An
agency
may
not
conduct
or
sponsor,
and
a
person
is
not
required
to
respond
to
a
collection
of
information
unless
it
displays
a
currently
valid
OMB
control
number.
The
OMB
control
numbers
for
EPA's
regulations
in
40
CFR
are
listed
in
40
CFR
part
9.
In
addition,
EPA
is
amending
the
table
in
40
CFR
part
9
of
currently
approved
OMB
control
numbers
for
various
regulations
to
list
the
regulatory
citations
for
the
information
requirements
contained
in
this
final
rule.

C.
Regulatory
Flexibility
Act
The
Regulatory
Flexibility
Act
(
RFA)
generally
requires
an
agency
to
prepare
a
regulatory
flexibility
analysis
for
any
rule
subject
to
notice
and
comment
rulemaking
requirements
under
the
Administrative
Procedure
Act
or
other
statute
unless
the
agency
certifies
that
the
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.
Small
entities
include
small
businesses,
small
organizations,
and
small
governmental
jurisdictions.

The
RFA
provides
default
definitions
for
each
type
of
small
entity.
Small
entities
are
defined
as:
(
1)
a
small
business
as
defined
by
the
Small
Business
Administrations's
(
SBA)

regulations
at
13
CFR
121.201;
(
2)
a
small
governmental
jurisdiction
that
is
a
government
of
a
city,
county,
town,
school
district
or
special
district
with
a
population
of
less
than
50,000;
and
(
3)

a
small
organization
that
is
any
"
not­
for­
profit
enterprise
which
is
independently
owned
and
operated
and
is
not
dominant
in
its
field."
However,
the
RFA
also
authorizes
an
agency
to
use
alternative
definitions
for
each
category
of
small
entity,
"
which
are
appropriate
to
the
activities
of
the
agency"
after
proposing
the
alternative
definition(
s)
in
the
Federal
Register
and
taking
243
comment.
5
U.
S.
C.
601(
3)
­
(
5).
In
addition,
to
establish
an
alternative
small
business
definition,

agencies
must
consult
with
SBA's
Chief
Council
for
Advocacy.

For
purposes
of
assessing
the
impacts
of
today's
rule
on
small
entities,
EPA
considered
small
entities
to
be
public
water
systems
serving
10,000
or
fewer
persons.
As
required
by
the
RFA,
EPA
proposed
using
this
alternative
definition
in
the
Federal
Register
(
63
FR
7620,

February
13,
1998),
requested
public
comment,
consulted
with
the
Small
Business
Administration
(
SBA),
and
finalized
the
alternative
definition
in
the
Consumer
Confidence
Reports
regulation
(
63
FR
44511,
August
19,
1998).
As
stated
in
that
Final
Rule,
the
alternative
definition
is
applied
to
this
regulation
as
well.

After
considering
the
economic
impacts
of
today's
final
rule
on
small
entities,
I
certify
that
this
action
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.

The
small
entities
regulated
by
this
final
rule
are
PWSs
serving
fewer
than
10,000
people.
We
have
determined
that
10192
small
surface
water
and
ground
water
under
the
direct
influence
of
surface
water
(
GWUDI)
systems
(
or
2.3816
%
of
all
small
surface
water
and
GWUDI
systems
affected
by
the
Stage
2
DBPR)
will
experience
an
impact
of
1%
or
greater
of
average
annual
revenues.
Of
the
10192,
440
small
surface
water
and
GWUDI
systems
(
or
10.04%
94
%
of
all
small
surface
water
and
GWUDI
systems
affected
by
the
Stage
2
DBPR)
will
experience
an
impact
of
3%
or
greater
of
average
annual
revenues.
Further,
276354
small
ground
water
systems
(
or
1.0.802
%
of
all
small
ground
water
systems
affected
by
the
Stage
2
DBPR)
will
experience
an
impact
of
1%
or
greater
of
average
annual
revenues.
Of
the
276354,
45
small
ground
water
systems
(
or
0.13
%
of
all
small
ground
water
systems
affected
by
the
Stage
2
DBPR)
will
experience
an
impact
of
3
%
3%
or
greater
of
average
annual
revenues.

Although
this
final
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities,
EPA
nonetheless
has
tried
to
reduce
the
impact
of
this
rule
on
small
244
entities.
The
Stage
2
DBPR
contains
a
number
of
provisions
to
minimize
the
impact
of
the
rule
on
systems
generally,
and
on
small
systems
in
particular.
For
example,
small
systems
have
a
longer
time
frame
to
comply
with
requirements
than
large
systems
(
see
§
141.600(
c)
and
§
141.620.(
c)).
The
final
rule
determines
monitoring
frequency
based
on
population
rather
than
plant­
based
monitoring
requirements
(
see
§
141.605
and
§
141.621(
a))
as
proposed.
Small
systems
will
also
have
to
take
fewer
samples
than
large
systems
due
to
the
40/
30
waiver
(
see
§
141.603(
a)),
for
which
small,
ground
water
systems
are
expected
to
be
able
to
qualify
for,
and
the
very
small
system
waiver
(
see
§
141.604).

Funding
may
be
available
from
programs
administered
by
EPA
and
other
Federal
agencies
to
assist
small
PWSs
in
complying
with
the
Stage
2
DBPR.
The
Drinking
Water
State
Revolving
Fund
(
DWSRF)
assists
PWSs
with
financing
the
costs
of
infrastructure
needed
to
achieve
or
maintain
compliance
with
SDWA
requirements.
Through
the
DWSRF,
EPA
awards
capitalization
grants
to
States,
which
in
turn
can
provide
low­
cost
loans
and
other
types
of
assistance
to
eligible
PWSs.
Loans
made
under
the
program
can
have
interest
rates
between
0
percent
and
market
rate
and
repayment
terms
of
up
to
20
years.
States
prioritize
funding
based
on
projects
that
address
the
most
serious
risks
to
human
health
and
assist
PWSs
most
in
need.

Congress
provided
the
DWSRF
program
$
8
billion
for
fiscal
years
1997
through
2004.

The
DWSRF
places
an
emphasis
on
small
and
disadvantaged
communities.
States
must
provide
a
minimum
of
15%
of
the
available
funds
for
loans
to
small
communities.
A
State
has
the
option
of
providing
up
to
30%
of
the
grant
awarded
to
the
State
to
furnish
additional
assistance
to
State­
defined
disadvantaged
communities.
This
assistance
can
take
the
form
of
lower
interest
rates,
principal
forgiveness,
or
negative
interest
rate
loans.
The
State
may
also
extend
repayment
terms
of
loans
for
disadvantaged
communities
to
up
to
30
years.
A
State
can
set
aside
up
to
2%

of
the
grant
to
provide
technical
assistance
to
PWSs
serving
communities
with
populations
fewer
245
than
10,000.

In
addition
to
the
DWSRF,
money
is
available
from
the
Department
of
Agriculture's
Rural
Utility
Service
(
RUS)
and
Housing
and
Urban
Development's
Community
Development
Block
Grant
(
CDBG)
program.
RUS
provides
loans,
guaranteed
loans,
and
grants
to
improve,
repair,
or
construct
water
supply
and
distribution
systems
in
rural
areas
and
towns
of
up
to
10,000
people.

In
fiscal
year
2003,
RUS
had
over
$
1.5
billion
of
available
funds
for
water
and
environmental
programs.
The
CDBG
program
includes
direct
grants
to
States,
which
in
turn
are
awarded
to
smaller
communities,
rural
areas,
and
coloñas
in
Arizona,
California,
New
Mexico,
and
Texas
and
direct
grants
to
U.
S.
territories
and
trusts.
The
CDBG
budget
for
fiscal
year
2003
totaled
over
$
4.4
billion.

Although
not
required
by
the
RFA
to
convene
a
Small
Business
Advocacy
Review
(
SBAR)
Panel
because
EPA
determined
that
the
proposed
rule
would
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities,
EPA
did
convene
a
panel
to
obtain
advice
and
recommendations
from
representatives
of
the
small
entities
potentially
subject
to
this
rule's
requirements.
For
a
description
of
the
SBAR
Panel
and
stakeholder
recommendations,

please
see
the
proposed
rule
(
USEPA
2003a).

D.
Unfunded
Mandates
Reform
Act
Title
II
of
the
Unfunded
Mandates
Reform
Act
of
1995
(
UMRA),
Public
Law
104­
4,

establishes
requirements
for
Federal
agencies
to
assess
the
effects
of
their
regulatory
actions
on
State,
local,
and
Tribal
governments
and
the
private
sector.
Under
section
202
of
the
UMRA,

EPA
generally
must
prepare
a
written
statement,
including
a
cost­
benefit
analysis,
for
proposed
and
final
rules
with
"
Federal
mandates"
that
may
result
in
expenditures
to
State,
local
and
Tribal
governments,
in
the
aggregate,
or
to
the
private
sector,
of
$
100
million
or
more
in
any
one
year.
246
Before
promulgating
an
EPA
rule
for
which
a
written
statement
is
needed,
section
205
of
the
UMRA
generally
requires
EPA
to
identify
and
consider
a
reasonable
number
of
regulatory
alternatives
and
adopt
the
least
costly,
most
cost­
effective
or
least
burdensome
alternative
that
achieves
the
objectives
of
the
rule.
The
provisions
of
section
205
do
not
apply
when
they
are
inconsistent
with
applicable
law.
Moreover,
section
205
allows
EPA
to
adopt
an
alternative
other
than
the
least
costly,
most
cost­
effective
or
least
burdensome
alternative
if
the
Administrator
publishes
with
the
final
rule
an
explanation
why
that
alternative
was
not
adopted.

Before
EPA
establishes
any
regulatory
requirements
that
may
significantly
or
uniquely
affect
small
governments,
including
Tribal
governments,
it
must
have
developed
under
section
203
of
the
UMRA
a
small
government
agency
plan.
The
plan
must
provide
for
notifying
potentially
affected
small
governments,
enabling
officials
of
affected
small
governments
to
have
meaningful
and
timely
input
in
the
development
of
EPA
regulatory
proposals
with
significant
Federal
intergovernmental
mandates,
and
informing,
educating,
and
advising
small
governments
on
compliance
with
the
regulatory
requirements.

EPA
has
determined
that
this
rule
does
notmay
contain
a
Ffederal
mandate
that
may
results
in
expenditures
of
$
100
million
or
more
for
the
State,
lLocal,
and
Tribal
governments,
in
the
aggregate,
or
in
the
private
sector
in
any
one
year.
The
total
estimated
annual
public
costs
for
this
rule
is
$
70.2
to
$
68.9
(
at
a
3
and
7
percent
discount
rate,
respectively)
and
the
private
costs
is
$
16.0
to
$
15.4
(
at
3
and
7
percent
rates,
respectively).
See
the
EA
for
more
detail
on
these
estimatesWhile
the
annualized
costs
fall
below
the
$
100
million
threshold,
the
costs
in
some
future
years
may
be
above
the
$
100
million
mark
as
public
drinking
water
systems
make
capital
investments
and
finance
these
through
bonds,
loans,
and
other
means.
EPA's
year
by
year
cost
tables
do
not
reflect
that
investments
through
bonds,
loans,
and
other
means
spread
out
these
costs
over
many
years.
The
cost
analysis
in
general
does
not
consider
that
some
systems
may
be
247
3%
Discount
Rate
7%
Discount
Rate
Percent
of
3%
Grand
Total
Costs
Percent
of
7%
Grand
Total
Costs
Surface
Water
Systems
Costs
41.4
$
41.2
$
53%
54%
Ground
Water
Systems
Costs
20.3
$
19.2
$
26%
25%
State
Costs
1.7
$
1.7
$
2%
2%
Tribal
Costs
0.4
$
0.4
$
1%
0%
Total
Public
63.8
$
62.5
$
81%
81%
Surface
Water
Systems
Costs
6.4
$
6.3
$
8%
8%
Ground
Water
Systems
Costs
8.5
$
8.0
$
11%
10%
Total
Private
15.0
$
14.3
$
19%
19%
GRAND
TOTAL
78.8
$
76.8
$
100%
100%
eligible
for
financial
assistance
such
as
low­
interest
loans
and
grants
through
such
programs
as
the
Drinking
Water
State
Revolving
Fund.

As
noted
earlier,
today's
final
rule
is
promulgated
pursuant
to
section
1412
(
b)(
1)(
A)
of
the
Safe
Drinking
Water
Act
(
SDWA),
as
amended
in
1996,
which
directs
EPA
to
promulgate
a
national
primary
drinking
water
regulation
for
a
contaminant
if
EPA
determines
that
the
contaminant
may
have
an
adverse
effect
on
the
health
of
persons,
occurs
in
PWSs
with
a
frequency
and
at
levels
of
public
health
concern,
and
regulation
presents
a
meaningful
opportunity
for
health
risk
reduction.

Section
VI
of
this
preamble
discusses
the
cost
and
benefits
associated
with
the
Stage
2
DBPR.
Details
are
presented
in
the
Economic
Analysis
(
USEPA
2005a).
Thus
today's
final
rule
is
not
subject
to
the
requirements
of
sections
202
and
205
of
the
UMRA.

Table
VII.
D­
1
Public
and
Private
Costs
for
the
Stage
2
DBPR
(
Annualized
at
3
and
7
Percent,
$
Millions)

Note:
Detail
may
not
add
due
to
independent
rounding.
Estimates
are
discounted
to
2003
and
given
in
2003
dollars.
Source:
Exhibits
3.2
and
7.5,
USEPA
2005a.

To
meet
the
UMRA
requirement
in
section
202,
EPA
analyzed
future
compliance
costs
and
possible
disproportionate
budgetary
effects.
The
Agency
believes
that
the
cost
estimates
and
regulatory
alternatives
indicated
earlier
and
discussed
in
more
detail
in
section
VI
of
this
248
preamble,
accurately
characterize
future
compliance
costs
of
today's
rule.

In
analyzing
disproportionate
impacts,
EPA
considered
the
impact
on
(
1)
different
regions
of
the
United
States,
(
2)
State,
local,
and
Tribal
governments,
(
3)
urban,
rural
and
other
types
of
communities,
and
(
4)
any
segment
of
the
private
sector.
This
analysis
is
presented
in
Chapter
7
of
the
Economic
Analysis
(
USEPA
2005a).
EPA
analyzed
four
regulatory
alternatives
and
selected
the
least
costly
of
these
in
accordance
with
UMRA
Section
205.

EPA
has
determined
that
the
Stage
2
DBPR
contains
no
regulatory
requirements
that
might
significantly
or
uniquely
affect
small
governments.
The
Stage
2
DBPR
affects
all
size
systems.
As
described
in
section
VII.
C,
EPA
has
certified
that
today's
rule
will
not
have
a
significant
economic
impact
on
a
substantial
number
of
small
entities.
Average
annual
expenditures
for
small
PWSsCWSs
to
comply
with
the
Stage
2
DBPR
range
from
$
3127.57
to
$
296.71
million
at
a
3
and
7
percent
discount
rate,
respectively.

Nevertheless,
in
developing
this
rule,
EPA
consulted
with
small
governments.
In
preparation
for
the
proposed
Stage
2
DBPR,
EPA
conducted
an
analysis
of
small
government
impacts
and
included
small
government
officials
or
their
designated
representatives
in
the
rulemaking
process
Consistent
with
the
intergovernmental
consultation
provisions
of
section
204
of
the
UMRA
and
Executive
Order
12875,
"
Enhancing
the
Intergovernmental
Partnership,"
EPA
has
already
initiated
consultations
with
the
governmental
entities
affected
by
this
rule.
The
consultations
are
described
in
the
proposed
rule
(
68
FR
49654,
August
18,
2003).

E.
Executive
Order
13132:
Federalism
Executive
Order
13132,
entitled
"
Federalism"
(
64
FR
43255,
August
10,
1999),
requires
EPA
to
develop
an
accountable
process
to
ensure
"
meaningful
and
timely
input
by
State
and
local
249
officials
in
the
development
of
regulatory
policies
that
have
federalism
implications."
"
Policies
that
have
federalism
implications"
is
defined
in
the
Executive
Order
to
include
regulations
that
have
"
substantial
direct
effects
on
the
States,
on
the
relationship
between
the
national
government
and
the
States,
or
on
the
distribution
of
power
and
responsibilities
among
the
various
levels
of
government."

This
final
rule
does
not
have
federalism
implications.
It
will
not
have
substantial
direct
effects
on
the
States,
on
the
relationship
between
national
government
and
the
States,
or
on
the
distribution
of
power
and
responsibilities
among
various
levels
of
government,
as
specified
in
Executive
Order
13132.
The
final
rule
has
one­
time
costs
for
implementation
of
approximately
$
7.8
million.
Thus,
Executive
Order
13132
does
not
apply
to
this
rule.

Although
section
6
of
Executive
Order
13132
does
not
apply
to
this
rule,
in
the
spirit
of
Executive
Order
13132,
and
consistent
with
EPA
policy
to
promote
communications
between
EPA
and
State
and
local
governments,
EPA
nonetheless
specifically
solicited
comment
on
the
proposed
rule
from
State
and
local
officials
and
did
consult
with
State
and
local
officials
in
developing
this
rule.
A
description
of
that
consultation
can
be
found
in
the
preamble
to
the
proposed
rule,
68
FR
49548,
(
August
18,
2003).

F.
Executive
Order
13175:
Consultation
and
Coordination
With
Indian
Tribal
Governments
Executive
Order
13175,
entitled
"
Consultation
and
Coordination
with
Indian
Tribal
Governments"
(
65
FR
67249,
November
9,
2000),
requires
EPA
to
develop
"
an
accountable
process
to
ensure
meaningful
and
timely
input
by
tribal
officials
in
the
development
of
regulatory
policies
that
have
tribal
implications."
Under
Executive
Order
13175,
EPA
may
not
issue
a
regulation
that
has
Tribal
implications,
that
imposes
substantial
direct
compliance
costs,
and
that
is
not
required
by
statute,
unless
the
Federal
government
provides
the
funds
necessary
to
pay
the
250
direct
compliance
costs
incurred
by
Tribal
governments,
or
EPA
consults
with
Tribal
officials
early
in
the
process
of
developing
the
proposed
regulation
and
develops
a
Tribal
summary
impact
statement.

EPA
has
concluded
that
this
final
rule
may
have
Tribal
implications,
because
it
may
impose
substantial
direct
compliance
costs
on
Tribal
governments,
and
the
Federal
government
will
not
provide
the
funds
necessary
to
pay
those
costs.

Accordingly,
EPA
provides
the
following
Tribal
summary
impact
statement
as
required
by
section
5(
b).
EPA
provides
further
detail
on
Tribal
impact
in
the
Economic
Analysis
for
the
Stage
2
Disinfectants
and
Disinfection
Byproduct
Rule
(
USEPA
2005a).
Total
Tribal
costs
are
estimated
to
be
approximately
$
403$
391,113773
per
year
(
at
a
3
percent
discount
rate)
and
this
cost
is
distributed
across
755
Tribal
systems.
The
cost
for
individual
systems
depend
on
system
size
and
source
water
type.
Of
the
755
Tribes
that
may
be
affected
in
some
form
by
the
Stage
2
DBPR,
654
use
ground
water
as
a
source
and
101
systems
use
surface
water
or
GWUDI.
Since
the
majority
of
Tribal
systems
are
ground
water
systems
serving
fewer
than
500
people,

approximately
415.26
percent
of
all
Tribal
systems
will
have
to
conduct
an
IDSE.
As
a
result,
the
Stage
2
DBPR
is
most
likely
to
have
an
impact
on
Tribes
using
surface
water
or
GWUDI
serving
more
than
500
people.

EPA
consulted
with
Tribal
officials
early
in
the
process
of
developing
this
regulation
to
permit
them
to
have
meaningful
and
timely
input
into
its
development.
Moreover,
in
the
spirit
of
Executive
Order
13175,
and
consistent
with
EPA
policy
to
promote
communications
between
EPA
and
Tribal
governments,
EPA
specifically
solicited
comment
on
the
proposed
rule
from
Tribal
officials.

As
required
by
section
7(
a),
EPA's
Tribal
Consultation
Official
has
certified
that
the
requirements
of
the
Executive
Order
has
been
met
in
a
meaningful
and
timely
manner.
A
copy
of
251
this
certification
has
been
included
in
the
docket
for
this
rule.

G.
Executive
order
13045:
Protection
of
Children
from
Environmental
Health
Risks
and
Safety
Risks
Executive
Order
13045:
"
Protection
of
Children
from
Environmental
Health
Risks
and
Safety
Risks"
(
62
FR
19885,
April
23,
1997)
applies
to
any
rule
that:
1)
is
determined
to
be
"
economically
significant"
as
defined
under
12866,
and;
2)
concerns
an
environmental
health
or
safety
risk
that
EPA
has
reason
to
believe
may
have
a
disproportionate
effect
on
children.
If
the
regulatory
action
meets
both
criteria,
the
Agency
must
evaluate
the
environmental
health
or
safety
effects
of
the
planned
rule
on
children,
and
explain
why
the
planned
regulation
is
preferable
to
other
potentially
effective
and
reasonably
feasible
alternatives
considered
by
the
Agency.

While
this
final
rule
is
not
subject
to
the
Executive
Order
because
it
is
not
economically
significant
as
defined
in
Executive
Order
12866,
EPA
nonetheless
has
reason
to
believe
that
the
environmental
health
or
safety
risk
(
i.
e.,
the
risk
associated
with
DBPs)
addressed
by
this
action
may
have
a
disproportionate
effect
on
children.
EPA
believes
that
the
Stage
2
DBPR
will
result
in
greater
risk
reduction
for
children
than
for
the
general
population.
The
results
of
the
assessments
are
contained
in
Section
VI.
I
of
this
preamble
and
in
the
Economic
Analysis
(
USEPA
2005a).
A
copy
of
all
documents
has
been
placed
in
the
public
docket
for
this
action.

H.
Executive
Order
13211:
Actions
Concerning
Regulations
That
Significantly
Affect
Energy
Supply,
Distribution,
or
Use
This
rule
is
not
a
"
significant
energy
action"
as
defined
in
Executive
Order
13211,

"
Actions
Concerning
Regulations
That
Significantly
Affect
Energy
Supply,
Distribution,
or
Use"

(
66
FR
28355,
May
22,
2001)
because
it
is
not
likely
to
have
a
significant
adverse
effect
on
the
252
supply,
distribution,
or
use
of
energy.
This
determination
is
based
on
the
following
analysis.

The
first
consideration
is
whether
the
Stage
2
DBPR
would
adversely
affect
the
supply
of
energy.
The
Stage
2
DBPR
does
not
regulate
power
generation,
either
directly
or
indirectly.
The
public
and
private
utilities
that
the
Stage
2
DBPR
regulates
do
not,
as
a
rule,
generate
power.

Further,
the
cost
increases
borne
by
customers
of
water
utilities
as
a
result
of
the
Stage
2
DBPR
are
a
low
percentage
of
the
total
cost
of
water,
except
for
a
very
few
small
systems
that
might
install
advanced
technologies
that
must
spread
that
cost
over
a
narrow
customer
base.
Therefore,

the
customers
that
are
power
generation
utilities
are
unlikely
to
face
any
significant
effects
as
a
result
of
the
Stage
2
DBPR.
In
sum,
the
Stage
2
DBPR
does
not
regulate
the
supply
of
energy,

does
not
generally
regulate
the
utilities
that
supply
energy,
and
is
unlikely
significantly
to
affect
the
customer
base
of
energy
suppliers.
Thus,
the
Stage
2
DBPR
would
not
translate
into
adverse
effects
on
the
supply
of
energy.

The
second
consideration
is
whether
the
Stage
2
DBPR
would
adversely
affect
the
distribution
of
energy.
The
Stage
2
DBPR
does
not
regulate
any
aspect
of
energy
distribution.

The
utilities
that
are
regulated
by
the
Stage
2
DBPR
already
have
electrical
service.
As
derived
later
in
this
section,
the
proposedfinal
rule
is
projected
to
increase
peak
electricity
demand
at
water
utilities
by
only
0.009
percent.
Therefore,
EPA
estimates
that
the
existing
connections
are
adequate
and
that
the
Stage
2
DBPR
has
no
discernable
adverse
effect
on
energy
distribution.

The
third
consideration
is
whether
the
Stage
2
DBPR
would
adversely
affect
the
use
of
energy.
Because
some
drinking
water
utilities
are
expected
to
add
treatment
technologies
that
use
electrical
power,
this
potential
impact
is
evaluated
in
more
detail.
The
analyses
that
underlay
the
estimation
of
costs
for
the
Stage
2
DBPR
are
national
in
scope
and
do
not
identify
specific
plants
or
utilities
that
may
install
treatment
in
response
to
the
rule.
As
a
result,
no
analysis
of
the
effect
on
specific
energy
suppliers
is
possible
with
the
available
data.
The
approach
used
to
estimate
the
253
impact
of
energy
use,
therefore,
focuses
on
national­
level
impacts.
The
analysis
estimates
the
additional
energy
use
due
to
the
Stage
2
DBPR
and
compares
that
analysis
to
the
national
levels
of
power
generation
in
terms
of
average
and
peak
loads.

The
first
step
in
the
analysis
is
to
estimate
the
energy
used
by
the
technologies
expected
to
be
installed
as
a
result
of
the
Stage
2
DBPR.
Energy
use
is
not
directly
stated
in
Technologies
and
Costs
for
Control
of
Microbial
Contaminantsthe
Final
Long
Term
2
Enhanced
Surface
Water
Treatment
Rule
and
Final
Stage
2
Disinfectants
and
Disinfection
By­
ProductsByproducts
Rule
(
USEPA
2003d5g),
but
the
annual
cost
of
energy
for
each
technology
addition
or
upgrade
necessitated
by
the
Stage
2
DBPR
is
provided.
An
estimate
of
plant­
level
energy
use
is
derived
by
dividing
the
total
energy
cost
per
plant
for
a
range
of
flows
by
an
average
national
cost
of
electricity
of
$
0.076/
kilowatt
hours
per
year
(
kWh/
yr)
(
USDOE
EIA
20024a).
These
calculations
are
shown
in
detail
in
the
Economic
Analysis
for
the
Stage
2
DBPR
(
USEPA
2005a).
The
energy
use
per
plant
for
each
flow
range
and
technology
is
then
multiplied
by
the
number
of
plants
predicted
to
install
each
technology
in
a
given
flow
range.
The
energy
requirements
for
each
flow
range
are
then
added
to
produce
a
national
total.
No
electricity
use
is
subtracted
to
account
for
the
technologies
that
may
be
replaced
by
new
technologies,
resulting
in
a
conservative
estimate
of
the
increase
in
energy
use.
The
incremental
national
annual
energy
usage
is
0.12
million
megawatt­
hours
(
MWh).

According
to
the
U.
S.
Department
of
Energy's
Information
Administration,
electricity
producers
generated
3,848
million
MWh
of
electricity
in
2003
(
USDOE
EIA
2004b).
Therefore,

even
using
the
highest
assumed
energy
use
for
the
Stage
2
DBPR,
the
rule
when
fully
implemented
would
result
in
only
a
0.003
percent
increase
in
annual
average
energy
use.

In
addition
to
average
energy
use,
the
impact
at
times
of
peak
power
demand
is
important.

To
examine
whether
increased
energy
usage
might
significantly
affect
the
capacity
margins
of
254
energy
suppliers,
their
peak
season
generating
capacity
reserve
was
compared
to
an
estimate
of
peak
incremental
power
demand
by
water
utilities.

Both
energy
use
and
water
use
peak
in
the
summer
months,
so
the
most
significant
effects
on
supply
would
be
seen
then.
In
the
summer
of
2003,
U.
S.
generation
capacity
exceeded
consumption
by
15
percent,
or
approximately
160,000
MW
(
USDOE
EIA
2004b).
Assuming
around­
the­
clock
operation
of
water
treatment
plants,
the
total
energy
requirement
can
be
divided
by
8,760
hours
per
year
to
obtain
an
average
power
demand
of
143.0428
MW.
A
more
detailed
derivation
of
this
value
is
shown
in
the
Economic
Analysis
for
the
Stage
2
DBPR
(
USEPA
2005a).
Assuming
that
power
demand
is
proportional
to
water
flow
through
the
plant
and
that
peak
flow
can
be
as
high
as
twice
the
average
daily
flow
during
the
summer
months,
about
286.0855
MW
could
be
needed
for
treatment
technologies
installed
to
comply
with
the
Stage
2
DBPR.
This
is
only
0.0187
percent
of
the
capacity
margin
available
at
peak
use.

Although
EPA
recognizes
that
not
all
areas
have
a
15
percent
capacity
margin
and
that
this
margin
varies
across
regions
and
through
time,
this
analysis
reflects
the
effect
of
the
rule
on
national
energy
supply,
distribution,
and
use.
While
certain
areas,
notably
California,
have
experienced
shortfalls
in
generating
capacity
in
the
recent
past,
a
peak
incremental
power
requirement
of
286.0855
MW
nationwide
is
not
likely
to
significantly
change
the
energy
supply,

distribution,
or
use
in
any
given
area.
Considering
this
analysis,
EPA
has
concluded
that
Stage
2
DBPR
will
not
have
any
significant
effect
on
the
use
of
energy,
based
on
annual
average
use
and
on
conditions
of
peak
power
demand.

I.
National
Technology
Transfer
and
Advancement
Act
As
noted
in
the
proposed
rule,
Section
12(
d)
of
the
National
Technology
Transfer
and
Advancement
Act
of
1995
("
NTTAA"),
Public
Law
104­
113,
section
12(
d)
(
15
U.
S.
C.
272
note)
255
directs
EPA
to
use
voluntary
consensus
standards
in
its
regulatory
activities
unless
to
do
so
would
be
inconsistent
with
applicable
law
or
otherwise
impractical.
Voluntary
consensus
standards
are
technical
standards
(
e.
g.,
materials
specifications,
test
methods,
sampling
procedures,
and
business
practices)
that
are
developed
or
adopted
by
voluntary
consensus
standard
bodies.
The
NTTAA
directs
EPA
to
provide
Congress,
through
OMB,
explanations
when
the
Agency
decides
not
to
use
available
and
applicable
voluntary
consensus
standards.

This
action
does
notrulemaking
involves
technical
standards.
EPA
proposed
13
methods,

however
those
methods
are
not
in
this
final
rule.
The
13
methods
have
been
added
to
another
final
rule
[
Reference
when
published].

has
decided
to
use
two
voluntary
consensus
methods
for
HAA5
(
Standard
Method
6251
B,
1998
in
the
20th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
and
Standard
Method
6251
B­
94,
1994
available
at
http://
www.
standardmethods.
org).
In
addition
to
these
two
consensus
methods,
EPA
is
also
approving
EPA
Method
552.3
for
HAA5,
which
also
can
be
used
to
measure
three
unregulated
HAAs
that
are
not
included
in
the
consensus
methods.

The
unregulated
HAAs
are
included
in
the
EPA
method
because
some
water
systems
monitor
for
them
in
order
to
better
understand
their
treatment
processes
and
provide
greater
public
health
protection.
EPA
is
approving
two
voluntary
consensus
standards
for
daily
monitoring
for
chlorite
(
Standard
Method
4500­
ClO
2
E,
1998,
in
the
20th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
and
Standard
Method
4500­
ClO
2
E­
00,
2000,
available
at
http://
www.
standardmethods.
org).
EPA
Method
327.0,
Revision
1.1
is
also
being
approved
for
daily
monitoring
for
both
chlorite
and
chlorine
dioxide
in
order
to
provide
an
alternative
to
the
titration
procedure
that
is
required
in
the
Standard
Methods.
EPA
is
approving
a
method
from
American
Society
for
Testing
and
Materials
International
for
bromate,
chlorite
and
bromide
analyses
(
ASTM
D
6581­
00,
2000,
ASTM
International.
Annual
Book
of
ASTM
Standards,
256
Volume
11.01,
American
Society
for
Testing
and
Materials
International,
2001
or
any
year
containing
the
cited
version
of
the
method
may
be
used).
EPA
is
also
approving
three
EPA
methods
(
EPA
Methods
317.0
Revision
2.0,
321.8,
and
326.0)
that
provide
greater
sensitivity
and
selectivity
for
bromate
than
the
ASTM
consensus
standard.
These
EPA
methods
are
required
in
order
to
provide
better
process
control
for
water
systems
using
ozone
in
the
treatment
process
and
to
allow
for
a
reduced
monitoring
option.
EPA
Methods
317.0
Revision
2.0
and
326.0
can
also
be
used
to
determine
chlorite
and
bromide.
Today's
action
approves
eight
voluntary
consensus
standards
for
determining
free,
combined,
and
total
chlorine
(
SM
4500­
Cl
D,
SM
4500­
Cl
F,
and
4500­
Cl
G,
1998,
in
the
20th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
and
SM
4500­
Cl
D­
00,
SM
4500­
Cl
F­
00,
and
4500­
Cl
G­
00,
2000
available
at
http://
www.
standardmethods.
org
and
ASTM
D
1253­
86(
96),
1996,
ASTM
International,
Annual
Book
of
ASTM
Standards,
Volume
11.01,
American
Society
for
Testing
and
Materials
International,
1996
or
any
year
containing
the
cited
version
of
the
method
may
be
used
and
ASTM
D
1253­
03,
2003,
ASTM
International,
Annual
Book
of
ASTM
Standards,

Volume
11.01,
American
Society
for
Testing
and
Materials
International,
2004
or
any
year
containing
the
cited
version
of
the
method
may
be
used).
EPA
is
approving
four
standards
for
determining
total
chlorine
(
SM
4500­
Cl
E
and
SM
4500­
Cl
I,
1998,
in
the
20th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
and
SM
4500­
Cl
E­
00
and
SM
4500­
Cl
I­
00,
2000
available
at
http://
www.
standardmethods.
org).
Two
standards
for
determining
free
chlorine
are
approved
in
today's
rule
(
SM
4500­
Cl
H,
1998,
in
the
20th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
and
SM
4500­
Cl
H­
00,
2000
available
at
http://
www.
standardmethods.
org).
Today's
action
approves
three
voluntary
consensus
standards
for
measuring
chlorine
dioxide
(
4500­
ClO
2
D
and
4500­
ClO
2
E,
1998,
in
the
20th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
and
4500­
ClO
2
257
E­
00,
2000
available
at
http://
www.
standardmethods.
org).
EPA
is
approving
six
standards
for
determining
TOC
and
DOC
(
SM
5310
B,
SM
5310
C,
and
SM
5310
D,
1998,
in
the
20th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
and
SM
5310
B­
00,
SM
5310
C­
00,
and
SM
5310
D­
00,
2000
available
at
http://
www.
standardmethods.
org).
Two
standards
for
determining
UV
254
are
approved
in
today's
rule
(
SM
5910
B,
1998,
in
the
20th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater
and
SM
5910
B­
00,

2000
available
at
http://
www.
standardmethods.
org).
EPA
is
also
approving
EPA
Method
415.3
Revision
1.1
for
the
determination
of
TOC
and
SUVA
(
DOC
and
UV
254
).
This
EPA
method
contains
method
performance
data
that
are
not
available
in
the
consensus
standards.

Copies
of
the
ASTM
standards
may
be
obtained
from
the
American
Society
for
Testing
and
Materials
International,
100
Barr
Harbor
Drive,
West
Conshohocken,
PA
19428­
2959.
The
Standard
Methods
may
be
obtained
from
the
American
Public
Health
Association,
1015
Fifteenth
Street,
NW,
Washington,
DC
20005.

J.
Executive
Order
12898:
Federal
Actions
to
Address
Environmental
Justice
in
Minority
Populations
or
Low­
Income
Populations
Executive
Order
12898
establishes
a
Federal
policy
for
incorporating
environmental
justice
into
Federal
agency
missions
by
directing
agencies
to
identify
and
address
disproportionately
high
and
adverse
human
health
or
environmental
effects
of
its
programs,

policies,
and
activities
on
minority
and
low­
income
populations.
EPA
has
considered
environmental
justice
related
issues
concerning
the
potential
impacts
of
this
action
and
consulted
with
minority
and
low­
income
stakeholders.
A
description
of
this
consultation
can
be
found
in
the
proposed
rule
(
USEPA
2003a).
258
K.
Consultations
with
the
Science
Advisory
Board,
National
Drinking
Water
Advisory
Council,

and
the
Secretary
of
Health
and
Human
Services
In
accordance
with
Section
1412
(
d)
and
(
e)
of
the
SDWA,
the
Agency
did
consulted
with
the
Science
Advisory
Board,
the
National
Drinking
Water
Advisory
Council
(
NDWAC),
and
the
Secretary
of
Health
and
Human
Services
on
today's
rule.

EPA
met
with
the
SAB
to
discuss
the
Stage
2
DBPR
on
June
13,
2001
(
Washington,
DC),

September
25­
26,
2001
(
teleconference),
and
December
10­
12,
2001
(
Los
Angeles,
CA).
Written
comments
from
the
December
2001
meeting
of
the
SAB
addressing
the
occurrence
analysis
and
risk
assessment
were
generally
supportive.
SAB
comments
are
discussed
in
greater
detail
within
the
proposal.

EPA
met
with
the
NDWAC
on
November
8,
2001,
in
Washington,
DC
to
discuss
the
Stage
2
DBPR
proposal.
The
Advisory
Committee
generally
supported
the
need
for
the
Stage
2
DBPR
based
on
health
and
occurrence
data,
but
also
stressed
the
importance
of
providing
flexibility
to
the
systems
implementing
the
rule.
The
results
of
these
discussions
are
included
in
the
docket
for
the
proposed
rule.

L.
Plain
Language
Executive
Order
12866
requires
each
agency
to
write
its
rules
in
plain
language.
Readable
regulations
help
the
public
find
requirements
quickly
and
understand
them
easily.
They
increase
compliance,
strengthen
enforcement,
and
decrease
mistakes,
frustration,
phone
calls,
appeals,
and
distrust
of
government.
EPA
made
every
effort
to
write
this
preamble
to
the
final
rule
in
as
clear,

concise,
and
unambiguous
manner
as
possible.

M.
Analysis
of
the
Likely
Effect
of
Compliance
with
the
Stage
2
DBPR
on
the
Technical,
259
Managerial,
and
Financial
Capacity
of
Public
Water
Systems
Section
1420(
d)(
3)
of
SDWA,
as
amended,
requires
that,
in
promulgating
a
National
Primary
Drinking
Water
Regulation
(
NPDWR),
the
Administrator
shall
include
an
analysis
of
the
likely
effect
of
compliance
with
the
regulation
on
the
technical,
managerial,
and
financial
(
TMF)

capacity
of
PWSs.
This
analysis
is
described
in
more
detail
and
can
be
found
in
the
Economic
Analysis
(
USEPA
2005a).
Analyses
reflect
only
the
impact
of
new
or
revised
requirements,
as
established
by
the
LT2ESWTR;
the
impacts
of
previously
established
requirements
on
system
capacity
are
not
considered.

EPA
has
defined
overall
water
system
capacity
as
the
ability
to
plan
for,
achieve,
and
maintain
compliance
with
applicable
drinking
water
standards.
Capacity
encompasses
three
components:
technical,
managerial,
and
financial.
Technical
capacity
is
the
physical
and
operational
ability
of
a
water
system
to
meet
SDWA
requirements.
This
refers
to
the
physical
infrastructure
of
the
water
system,
including
the
adequacy
of
source
water
and
the
adequacy
of
treatment,
storage,
and
distribution
infrastructure.
It
also
refers
to
the
ability
of
system
personnel
to
adequately
operate
and
maintain
the
system
and
to
otherwise
implement
requisite
technical
knowledge.
Managerial
capacity
is
the
ability
of
a
water
system
to
conduct
its
affairs
to
achieve
and
maintain
compliance
with
SDWA
requirements.
Managerial
capacity
refers
to
the
system's
institutional
and
administrative
capabilities.
Financial
capacity
is
a
water
system's
ability
to
acquire
and
manage
sufficient
financial
resources
to
allow
the
system
to
achieve
and
maintain
compliance
with
SDWA
requirements.

EPA
estimated
the
impact
of
the
Stage
2
DBPR
on
small
and
large
system
capacity
as
a
result
of
the
measures
that
systems
are
expected
to
adopt
to
meet
the
requirements
of
the
rule
(
e.
g.,
selecting
monitoring
sites
for
the
IDSE,
installing/
upgrading
treatment,
operator
training,

communication
with
regulators
and
the
service
community,
etc.).
The
Stage
2
DBPR
may
have
a
260
substantial
impact
on
the
capacity
of
the
1,743
plants
in
small
systems
and
518
plants
in
large
systems
that
must
make
changes
to
their
treatment
process
to
meet
the
Stage
2
DBPR
requirements.
However,
while
the
impact
to
these
systems
is
potentially
significant,
only
3.8
percent
of
all
plants
regulated
under
the
Stage
2
DBPR
(
2,261
of
60,220)
will
be
affected
by
this
requirement.
Since
individual
systems
may
employ
more
than
one
plant,
it
is
likely
that
fewer
than
1,620
systems
(
3.4
percent
of
48,293
systems)
will
be
affected
by
this
requirement.
The
new
IDSE
and
monitoring
requirements
are
expected
to
have
a
small
impact
on
the
technical
and
managerial
capacity
of
small
systems,
a
moderate
impact
on
the
financial
capacity
of
some
small
systems,
and
a
much
smaller
impact
on
large
systems.
The
capacity
of
systems
that
must
conduct
an
operational
evaluation
will
only
be
impacted
in
a
minor
way,
while
those
systems
that
must
only
familiarize
themselves
with
the
rule
(
the
large
majority
of
systems)
will
not
face
any
capacity
impact
as
a
result
of
the
Stage
2
DBPR.

MN.
Congressional
Review
Act
The
Congressional
Review
Act,
5
U.
S.
C.
801
et
seq.,
as
added
by
the
Small
Business
Regulatory
Enforcement
Fairness
Act
of
1996,
generally
provides
that
before
a
rule
may
take
effect,
the
agency
promulgating
the
rule
must
submit
a
rule
report,
which
includes
a
copy
of
the
rule,
to
each
House
of
the
Congress
and
to
the
Comptroller
General
of
the
United
States.
EPA
will
submit
a
report
containing
this
rule
and
other
required
information
to
the
U.
S.
Senate,
the
U.
S.
House
of
Representatives,
and
the
Comptroller
General
of
the
United
States
prior
to
publication
of
the
rule
in
the
Federal
Register.
A
Major
rule
cannot
take
effect
until
60
days
after
it
is
published
in
the
Federal
Register.
This
action
is
a
"
major
rule"
as
defined
by
5
U.
S.
C.

804(
2).
This
rule
will
be
effective
[
INSERT
DATE
60
DAYS
AFTER
DATE
OF
PUBLICATION
IN
THE
FEDERAL
REGISTER].
261
VIII.
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1998.
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DC
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Aschengrau,
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1989.
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Cantor,
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R.
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A.
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D.
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1987.
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Bromate
Analysis.
Revision
1.0.
EPA
815­
R­

03­
007.
(
Available
at
http://
www.
epa.
gov/
safewater/
methods/
sourcalt.
html.)

USEPA.
2003a.
National
Primary
Drinking
Water
Regulations:
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule;
National
Primary
and
Secondary
Drinking
Water
Regulations:
Approval
of
Analytical
Methods
for
Chemical
Contaminants;
Proposed
Rule.

68
FR
49548,
August
18,
2003.

USEPA.
2003b.
Integrated
Risk
Information
System
(
IRIS).
Toxicologcal
Review
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278
Dichloroacetic
Acid:
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Review
Draft.
EPA
635/
R­
03/
007.

http://
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epa.
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iris/
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0654.
htm
USEPA.
2003c.
Stage
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EPA
68­
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99­
206.

USEPA.
2003d.
Technologies
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USEPA.
2003e.
Draft
Significant
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Washington,
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EPA
815 
D 
03 
004.

USEPA.
2003f.
Method
552.3.
Determination
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Haloacetic
Acids
and
Dalapon
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Drinking
Water
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Liquid­
liquid
Extraction,
Derivatization,
and
Gas
Chromatography
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Revision
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EPA­
815­
B­
03­
002.
(
Available
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epa.
gov/
safewater/
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html.)

USEPA.
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Guidelines
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National
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National
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Analysis
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Proposed
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696
FR
18166,
April
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2004.

USEPA.
2005a.
Economic
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DBPRDisinfectants
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Washington,
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EPA
XXX­
X­
XX­
XXX815­
R­
05­
010.

USEPA.
2005b.
Drinking
Water
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Document
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Washington,
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EPA
###­#­##­###
822­
R­
05­
011.

USEPA.
2005c.
Drinking
Water
Criteria
Document
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Washington,
DC.
EPA
###­#­##­###
822­
R­
05­
007.

USEPA.
2005d.
Drinking
Water
Addendum
to
the
Criteria
Document
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MCAAMonochloroacetic
Acid.
Washington,
DC.
EPA
###­#­##­###
822­
R­
05­
008.
279
USEPA.
2005e.
Drinking
Water
Addendum
to
the
Criteria
Document
for
TCAATrichloroacetic
Acid.
Washington,
DC.
EPA
###­#­##­###
822­
R­
05­
010.

USEPA.
2005f.
Stage
2
Occurrence
Assessment
for
the
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule.
Washington,
DC.
EPA
###­#­##­###
815­
R­
05­
011.

USEPA.
2005g.
Initial
Distribution
System
Evaluation
Guidance
Manual.
Washington,
DC.
EPA
### # ## ###.

USEPA.
2005h.
Guidelines
Establishing
Test
Procedures
for
the
Analysis
of
Pollutants
Under
the
Clean
Water
Act;
National
Primary
Drinking
Water
Regulations;
and
National
Secondary
Drinking
Water
Regulations;
Analysis
and
Sampling
Procedures;
Final
Rule.

FR
XX:
XX:
XXXXX­
XXXXX.
(
Date).

USEPA.
2005i.
Technologies
and
Costs
for
the
Control
of
Microbial
ContaminantsFinal
Long
Term
2
Enhanced
Surface
Water
Treatment
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Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule.
Washington,
DC.
EPA
###­#­##­###.

USEPA.
2005j815­
R­
05­
012.

USEPA.
2005h.
Method
327.0.
Determination
of
Chlorine
Dioxide
and
Chlorite
Ion
in
Drinking
Water
Using
Lissamine
Green
B
and
Horseradish
Peroxidase
with
Detection
by
Visible
Spectrophotometry.
Revision
1.1.
EPA
815­
R­
05­
008.
(
Available
at
http://
www.
epa.
gov/
safewater/
methods/
sourcalt.
html.)

USEPA.
2005i.
Guidelines
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carcinogen
risk
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Office
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Research
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Development,
Washington,
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EPA/
630/
P­
03/
001F.
Available
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at
http://
cfpub.
epa.
gov/
ncea/.

USEPA.
2005kj.
Supplemental
guidance
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assessing
susceptibility
from
early­
life
exposure
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Office
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Research
and
Development,
Washington,
DC.

EPA/
630/
R­
03/
003F.
Available
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http://
cfpub.
epa.
gov/
ncea/.
280
USEPA.
2005lk.
Office
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Water
Occurrence
and
Health
Advisory
Values
Addendum
forto
the
IRIS
Toxicological
Review
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Dichloroacetic
Acid.
Washington,
DC.
EPA
###­#­##­###.
822­
R­
05­
009.

USEPA.
2005l.
Method
415.3.
Determination
of
Total
Organic
Carbon
and
Specific
UV
Absorbance
at
254
nm
in
Source
Water
and
Drinking
Water.
Revision
1.1.
EPA/
600/
R­

05/
055.
(
Available
at
http://
www.
epa.
gov/
nerlcwww/
ordmeth.
htm.)

USEPA.
2005m.
Unregulated
Contaminant
Monitoring
Regulation
(
UCMR)
for
Public
Water
Systems
Revions;
Proposed
Rule.
70
FR
49094,
August
22,
2005.

USEPA.
2005n.
Information
Collection
Request
for
National
Primary
Drinking
Water
Regulations:
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule.
Washington,

DC.
EPA
815­
Z­
05­
002.

USEPA.
2006.
Initial
Distribution
System
Evaluation
Guidance
Manual
for
the
Final
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule.
Washington,
DC.
EPA
815­
B­
06­
002.

USFDA
(
Food
and
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1994.
Sanitizing
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21
Code
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http://
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gpoaccess.
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cgi/
t/
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text­
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c=
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Medicina
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27­
35.
[(
Spanish]).

Villanueva,
C.
M.,
Fernandez,
F.,
Malats,
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J.
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Metaanalysis
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57:
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173.

Villanueva,
C.
M.,
K.
P.
Cantor,
S.
Cordier,
J.
J.
K.
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W.
D.
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C.
F.
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S.
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Kogevinas.
2004.
Disinfection
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281
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367.

Vinceti,
M.,
G.
Fantuzzi,
L.
Monici,
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2004.
A
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cohort
study
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trihalomethane
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drinking
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and
cancer
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northern
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Science
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Total
Environment.
330(
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3):
47­
53.

Vineis,
P.
2004.
A
self­
fulfilling
prophecy:
are
we
underestimating
the
role
of
the
environment
in
gene 
environment
interaction
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International
Journal
of
Epidemiology.
33:
945­

946.

Waller,
K.,
S.
H.
Swan,
G.
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B.
Hopkins.
1998.
Trihalomethanes
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and
spontaneous
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Epidemiology.
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Waller,
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H.
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G.
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2001.
Influence
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abortion.
Journal
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Analysis
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Environmental
Epidemiology.

11(
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531.

Weinberg,
H.
S.,
S.
W.
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S.
D.
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A.
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2002.
The
Occurrence
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Disinfection
By­
Products
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DBPs)
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Water:
Results
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Study,
U.
S.
Environmental
Protection
Agency,
National
Exposure
Research
Laboratory,
Athens,
GA.
EPA/
600/
R­
02/
068.

http://
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epa.
gov/
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pdf.

WHO.
2000.
World
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International
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Chemical
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IPCS).

Environmental
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Windham,
GC,
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1992.
Tap
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Chlorination
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Environ
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282
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1992.

Spontaneous
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[
National
Primary
Drinking
Water
Regulations:
Stage
2
Disinfectants
and
Disinfection
Byproducts
Rule,
Page
264
of
314.]

283
List
of
Subjects
40
CFR
Part
9
Reporting
and
recordkeeping
requirements.

40
CFR
Part
141
Environmental
protection,
Chemicals,
Indians­
lands,
Incorporation
by
reference,

Intergovernmental
relations,
Radiation
protection,
Reporting
and
recordkeeping
requirements,

Water
supply.

40
CFR
Part
142
Environmental
protection,
Administrative
practice
and
procedure,
Chemicals,

Indianslands
Radiation
protection,
Reporting
and
recordkeeping
requirements,
Water
supply.

Dated:

________________________________________
Stephen
L.
Johnson,
Administrator
For
the
reasons
set
forth
in
the
preamble,
title
40
chapter
I
of
the
Code
of
Federal
Regulations
is
amended
as
follows:

PART
9
­
OMB
Approvals
under
the
Paperwork
Reduction
Act
1.
The
authority
citation
for
part
9
continues
to
read
as
follows:

Authority:
7
U.
S.
C.
135
et
seq.,
136­
136y;
15
U.
S.
C.
2001,
2003,
2005,
2006,
2601­
2671;
21
284
U.
S.
C.
331j,
346a,
348;
31
U.
S.
C.
9701;
33
U.
S.
C.
1251
et
seq.,
1311,
1313d,
1314,
1318,
1321,
1326,

1330,
1342,
1344,
1345
(
d)
and
(
e),
1361;
Executive
Order
11735,
38
FR
21243,
3
CFR,
1971­
1975
Comp.
p.
973;
42
U.
S.
C.
241,
242b,
243,
246,
300f,
300g,
300g­
1,
300g­
2,
300g­
3,
300g­
4,
300g­
5,

300g­
6,
300j­
1,
300j­
2,
300j­
3,
300j­
4,
300j­
9,
1857
et
seq.,
6901­
6992k,
7401­
7671q,
7542,
9601­
9657,

11023,
11048.

2.
In
§
9.1
the
table
is
amended
by
addingas
follows:

a.
under
the
indicated
heading
and"
National
Primary
Drinking
Water
Regulations
Implementation"
by
adding
entries
in
numerical
order:

a.
Entries
§
141
for
"
§
141.600
­
141.605,
141.620
­
141.626,
and
141.630,

b.
By
revising
the
entry
§
142.14(
a)
to
read
as
follows,
and
c.
By
adding
a
new
entry
§
142.16(
m).
629".

b.
under
the
heading
"
National
Primary
Drinking
Water
Regulations
Implementation"
by
removing
entries
"
§
142.14(
a),
142.14(
a)
­
(
d)(
3)"
and
adding
entries
in
numerical
order
for
"
142.14(
a)
(
1)
­
(
7),

142.14(
a)(
8),
142.14(
b)
­
(
d)
and
142.16(
m)
"
as
follows:

§
9.1
OMB
approvals
under
the
Paperwork
Reduction
Act.

*
*
*
*
*

40
CFR
citation
OMB
control
No.

*
*
*
*
*
*
*
*

*
*

National
Primary
Drinking
Water
Regulations
*
*
*
*
*
*
*
*

*
*

141.600
­
141.605
2040­
XXXX2040­
0265
141.620
­
141.626
2040­
XXXX2040­
0265
285
141.629
2040­
XXXX2040­
0265
National
Primary
Drinking
Water
Regulations
Implementation
*
*
*
*

*
1
4
2
.
1
4
(
a
)
2
0
4
0
­
0
2
2
9
,

2
0
4
0
­
0
0
9
0
,

2
0
4
0
­
L
T
2
'
s
#

2040­
XXXX
*
*
**
*
*
*
*
*
*
*

142.14(
a)(
1)
­
(
7)
142.14(
a)(
8)
142.14
(
b)
­
(
d)
2040­
0205
2040­
0265
2040­
0090
*
*
*
*
*
*
*

142.16(
m)
2040­
XXXX2040­
0265
*
*
*
*
*

PART
141
­
National
Primary
Drinking
Water
Regulations
3.
The
authority
citation
for
part
141
continues
to
read
as
follows:

Authority:
42
U.
S.
C.
300f,
300g­
1,
300g­
2,
300g­
3,
300g­
4,
300g­
5,
300g­
6,
300j­
4,
300j­
9,
and
300j­
11.

4.
Section
141.2
is
amended
by
adding,
in
alphabetical
order,
definitions
for
"
Combined
distribution
system",
"
Consecutive
system",
"
Dual
sample
sets",
"
Finished
water",
"
GAC20",
"
Locational
running
annual
average",
and
"
Wholesale
system"
and
modifyingrevising
the
definition
of
"
GAC10"
to
read
as
follows:

§
141.2
Definitions.

*
*
*
*
*

Combined
distribution
system
is
the
interconnected
distribution
system
consisting
of
the
distribution
systems
of
wholesale
systems
and
of
the
consecutive
systems
that
receive
finished
water.
286
*
*
*
*
*

Consecutive
system
is
a
public
water
system
that
receives
some
or
all
of
its
finished
water
from
one
or
more
wholesale
systems.
Delivery
may
be
through
a
direct
connection
or
through
the
distribution
system
of
one
or
more
consecutive
systems.

*
*
*
*
*

Dual
sample
set
is
a
set
of
two
samples
collected
at
the
same
time
and
same
location,
with
one
sample
analyzed
for
TTHM
and
the
other
sample
analyzed
for
HAA5.
Dual
sample
sets
are
collected
for
the
purposes
of
conducting
an
IDSE
under
subpart
U
of
this
part
and
determining
compliance
with
the
TTHM
and
HAA5
MCLs
under
subpart
V
of
this
part.

*
*
*
*
*

Finished
water
is
water
that
is
introduced
into
the
distribution
system
of
a
public
water
system
and
is
intended
for
distribution
and
consumption
without
further
treatment,
except
as
treatment
necessary
to
maintain
water
quality
in
the
distribution
system
(
e.
g.,
booster
disinfection,
addition
of
corrosion
control
chemicals).

*
*
*
*
*

GAC10
means
granular
activated
carbon
filter
beds
with
an
empty­
bed
contact
time
of
10
minutes
based
on
average
daily
flow
and
a
carbon
reactivation
frequency
of
every
180
days,
except
that
the
reactivation
frequency
for
GAC10
used
as
a
best
available
technology
for
compliance
with
subpart
V
MCLs
under
§
141.64(
b)(
2)
shall
be
120
days.

GAC20
means
granular
activated
carbon
filter
beds
with
an
empty­
bed
contact
time
of
20
minutes
based
on
average
daily
flow
and
a
carbon
reactivation
frequency
of
every
240
days.

*
*
*
*
*

Locational
running
annual
average
(
LRAA)
is
the
average
of
sample
analytical
results
for
samples
taken
at
a
particular
monitoring
location
during
the
previous
four
calendar
quarters.

*
*
*
*
*
287
Wholesale
system
is
a
public
water
system
that
treats
source
water
as
necessary
to
produce
finished
water
and
then
delivers
some
or
all
of
that
finished
water
to
another
public
water
system.
Delivery
may
be
through
a
direct
connection
or
through
the
distribution
system
of
one
or
more
consecutive
systems.

5.
Section
141.12
is
amended
by
deleting
all
text
to
read
as
follows:

§
141.12
[
Reserved]
removed
and
reserved.

6.
Section
141.30
is
amended
by
deleting
all
text
to
read
as
follows:

§
141.30
[
Reserved]
removed.

7.
Section
141.32
is
amended
by
deleting
all
text
to
read
as
follows:

§
141.32
[
Reserved]
removed
and
reserved.

8.
Section
141.33
is
amended
by
revising
the
first
sentence
of
paragraph
(
a)
introductory
text
and
adding
paragraph
(
f)
to
read
as
follows:

§
141.33
Record
maintenance.

*
*
*
*
*

(
a)
Records
of
microbiological
analyses
and
turbidity
analyses
made
pursuant
to
this
part
shall
be
kept
for
not
less
than
5
years.
*
*
*

*
*
*
*
*

(
f)
Copies
of
monitoring
plans
developed
pursuant
to
this
part
shall
be
kept
for
the
same
period
of
time
as
the
records
of
analyses
taken
under
the
plan
are
required
to
be
kept
under
paragraph
(
a)
or
ofor
three
years
after
modification,
whichever
is
longer
this
section,
except
as
specified
elsewhere
in
this
part.
288
9.
Section
141.53
is
amended
by
removingrevising
the
table
and
adding
in
its
place
the
following
tableto
read
as
follows:

§
141.53
Maximum
contaminant
level
goals
for
disinfection
byproducts.

*
*
*
*
*

Disinfection
byproduct
MCLG
(
mg/
L)

Bromodichloromethane
Bromoform
Bromate
Chlorite
Chloroform
Dibromochloromethane
Dichloroacetic
acid
Monochloroacetic
acid
Trichloroacetic
acid
zero
zero
zero
0.8
0.07
0.06
zero
0.07
0.02
10.
Section
141.64
is
revised
to
read
as
follows:

§
141.64
Maximum
contaminant
levels
for
disinfection
byproducts.

(
a)
Bromate
and
chlorite.
The
maximum
contaminant
levels
(
MCLs)
for
bromate
and
chlorite
are
as
follows:

Disinfection
byproduct
MCL
(
mg/
L)

Bromate
Chlorite
0.010
1.0
(
1)
Compliance
dates
for
CWSs
and
NTNCWSs.
Subpart
H
systems
serving
10,000
or
more
persons
289
must
comply
with
this
paragraph
(
a)
beginning
January
1,
2002.
Subpart
H
systems
serving
fewer
than
10,000
persons
and
systems
using
only
ground
water
not
under
the
direct
influence
of
surface
water
must
comply
with
this
paragraph
(
a)
beginning
January
1,
2004.

(
2)
The
Administrator,
pursuant
to
section
1412
of
the
Act,
hereby
identifies
the
following
as
the
best
technology,
treatment
techniques,
or
other
means
available
for
achieving
compliance
with
the
maximum
contaminant
levels
for
bromate
and
chlorite
identified
in
this
paragraph
(
a):

Disinfection
byproduct
Best
available
technology
Bromate
Chlorite
Control
of
ozone
treatment
process
to
reduce
production
of
bromate
Control
of
treatment
processes
to
reduce
disinfectant
demand
and
control
of
disinfection
treatment
processes
to
reduce
disinfectant
levels
(
b)
TTHM
and
HAA5.

(
1)
Subpart
L
­
RAA
compliance.
(
i)
Compliance
dates.
Subpart
H
systems
serving
10,000
or
more
persons
must
comply
with
this
paragraph
(
b)(
1)
beginning
January
1,
2002.
Subpart
H
systems
serving
fewer
than
10,000
persons
and
systems
using
only
ground
water
not
under
the
direct
influence
of
surface
water
must
comply
with
this
paragraph
(
b)(
1)
beginning
January
1,
2004.
All
systems
must
comply
with
these
MCLs
until
the
date
specified
for
subpart
V
compliance
in
§
141.620(
c).

Disinfection
byproduct
MCL
(
mg/
L)

Total
trihalomethanes
(
TTHM)
Haloacetic
acids
(
five)
(
HAA5)
0.080
0.060
(
ii)
The
Administrator,
pursuant
to
section
1412
of
the
Act,
hereby
identifies
the
following
as
the
best
technology,
treatment
techniques,
or
other
means
available
for
achieving
compliance
with
the
maximum
contaminant
levels
for
TTHM
and
HAA5
identified
in
this
paragraph
(
b)(
1):

Disinfection
byproduct
Best
available
technology
Total
trihalomethanes
(
TTHM)
and
Haloacetic
acids
(
five)
(
HAA5)
Enhanced
coagulation
or
enhanced
softening
or
GAC10,
with
chlorine
as
the
primary
and
residual
disinfectant
(
2)
Subpart
V
­
LRAA
compliance.
(
i)
Compliance
dates.
The
subpart
V
MCLs
for
TTHM
and
HAA5
must
be
complied
with
as
a
locational
running
annual
average
at
each
monitoring
location
beginning
the
290
date
specified
for
subpart
V
compliance
in
§
141.620(
c).

Disinfection
byproduct
MCL
(
mg/
L)

Total
trihalomethanes
(
TTHM)
Haloacetic
acids
(
five)
(
HAA5)
0.080
0.060
(
ii)
The
Administrator,
pursuant
to
section
1412
of
the
Act,
hereby
identifies
the
following
as
the
best
technology,
treatment
techniques,
or
other
means
available
for
achieving
compliance
with
the
maximum
contaminant
levels
for
TTHM
and
HAA5
identified
in
this
paragraph
(
b)(
2)
for
all
systems
that
disinfect
their
source
water:

Disinfection
byproduct
Best
available
technology
Total
trihalomethanes
(
TTHM)
and
Haloacetic
acids
(
five)
(
HAA5)
Enhanced
coagulation
or
enhanced
softening,
plus
GAC10;
or
nanofiltration
with
a
molecular
weight
cutoff
#
1000
Daltons;
or
GAC20
(
iii)
The
Administrator,
pursuant
to
section
1412
of
the
Act,
hereby
identifies
the
following
as
the
best
technology,
treatment
techniques,
or
other
means
available
for
achieving
compliance
with
the
maximum
contaminant
levels
for
TTHM
and
HAA5
identified
in
this
paragraph
(
b)(
2)
for
consecutive
systems
and
applies
only
to
the
disinfected
water
that
consecutive
systems
buy
or
otherwise
receive:

Disinfection
byproduct
Best
available
technology
Total
trihalomethanes
(
TTHM)
and
Haloacetic
acids
(
five)
(
HAA5)
Systems
serving
$
10,000:
Improved
distribution
system
and
storage
tank
management
to
reduce
detentionresidence
time,
plus
the
use
of
chloramines
for
disinfectant
residual
maintenance
Systems
serving
<
10,000:
Improved
distribution
system
and
storage
tank
management
to
reduce
detentionresidence
time
11.
Section
141.131
is
amended
as
follows:

a.
by
revising
paragraph
(
a),

b.
by
revising
paragraphs
(
b)(
1)
and
(
b)(
2),

c.
by
revising
the
first
sentencetable
in
paragraph
(
a)(
1)
and
replacing
paragraph
(
b)(
2)
to
read
as
follows:
c)(
1),

d.
by
revising
paragraphs
(
d)(
2),
(
d)(
3),
(
d)(
4)(
i),
and
(
d)(
4)(
ii),
291
e.
by
adding
paragraph
(
d)(
6).

§
141.131
Analytical
requirements.

(
a)
General.
(
1)
Systems
must
use
only
the
analytical
methods
specified
in
this
section,
or
their
equivalent
as
approved
by
EPA,
to
demonstrate
compliance
with
the
requirements
of
this
subpart
and
with
the
requirements
of
subparts
U
and
V.
*
*
*

*
*
*
*
*
of
this
part.
These
methods
are
effective
for
compliance
monitoring
February
16,
1999,
unless
a
different
effective
date
is
specified
in
this
section
or
by
the
State.

(
2)
The
following
documents
are
incorporated
by
reference.
The
Director
of
the
Federal
Register
approves
this
incorporation
by
reference
in
accordance
with
5
U.
S.
C.
552(
a)
and
1
CFR
part
51.
Copies
may
be
inspected
at
EPA's
Drinking
Water
Docket,
1301
Constitution
Avenue,
NW.,
EPA
West,
Room
B102,

Washington,
DC
20460,
or
at
the
National
Archives
and
Records
Administration
(
NARA).
For
information
on
the
availability
of
this
material
at
NARA,
call
202­
741­
6030,
or
go
to:

http://
www.
archives.
gov/
federal_
register/
code_
of_
federal_
regulations/
ibr_
locations.
html.
EPA
Method
552.1
is
in
Methods
for
the
Determination
of
Organic
Compounds
in
Drinking
Water­
Supplement
II,

USEPA,
August
1992,
EPA/
600/
R­
92/
129
(
available
through
National
Information
Technical
Service
(
NTIS),
PB92­
207703).
EPA
Methods
502.2,
524.2,
551.1,
and
552.2
are
in
Methods
for
the
Determination
of
Organic
Compounds
in
Drinking
Water­
Supplement
III,
USEPA,
August
1995,

EPA/
600/
R­
95/
131
(
available
through
NTIS,
PB95­
261616).
EPA
Method
300.0
is
in
Methods
for
the
Determination
of
Inorganic
Substances
in
Environmental
Samples,
USEPA,
August
1993,
EPA/
600/
R­

93/
100
(
available
through
NTIS,
PB94­
121811).
EPA
Methods
300.1
and
321.8
are
in
Methods
for
the
Determination
of
Organic
and
Inorganic
Compounds
in
Drinking
Water,
Volume
1,
USEPA,
August
2000,
EPA
815­
R­
00­
014
(
available
through
NTIS,
PB2000­
106981).
EPA
Method
317.0,
Revision
2.0,

"
Determination
of
Inorganic
Oxyhalide
Disinfection
By­
Products
in
Drinking
Water
Using
Ion
292
Chromatography
with
the
Addition
of
a
Postcolumn
Reagent
for
Trace
Bromate
Analysis,"
USEPA,
July
2001,
EPA
815­
B­
01­
001,
EPA
Method
326.0,
Revision
1.0,
"
Determination
of
Inorganic
Oxyhalide
Disinfection
By­
Products
in
Drinking
Water
Using
Ion
Chromatography
Incorporating
the
Addition
of
a
Suppressor
Acidified
Postcolumn
Reagent
for
Trace
Bromate
Analysis,"
USEPA,
June
2002,
EPA
815­
R­

03­
007,
EPA
Method
327.0,
Revision
1.1,
"
Determination
of
Chlorine
Dioxide
and
Chlorite
Ion
in
Drinking
Water
Using
Lissamine
Green
B
and
Horseradish
Peroxidase
with
Detection
by
Visible
Spectrophotometry,"
USEPA,
May
2005,
EPA
815­
R­
05­
008
and
EPA
Method
552.3,
Revision
1.0,

"
Determination
of
Haloacetic
Acids
and
Dalapon
in
Drinking
Water
by
Liquid­
liquid
Microextraction,

Derivatization,
and
Gas
Chromatography
with
Electron
Capture
Detection,"
USEPA,
July
2003,
EPA­
815­

B­
03­
002
can
be
accessed
and
downloaded
directly
on­
line
at
www.
epa.
gov/
safewater/
methods/
sourcalt.
html.
EPA
Method
415.3,
Revision
1.1,
"
Determination
of
Total
Organic
Carbon
and
Specific
UV
Absorbance
at
254
nm
in
Source
Water
and
Drinking
Water,"

USEPA,
February
2005,
EPA/
600/
R­
05/
055
can
be
accessed
and
downloaded
directly
on­
line
at
www.
epa.
gov/
nerlcwww/
ordmeth.
htm.
Standard
Methods
4500­
Cl
D,
4500­
Cl
E,
4500­
Cl
F,
4500­
Cl
G,

4500­
Cl
H,
4500­
Cl
I,
4500­
ClO2
D,
4500­
ClO2
E,
6251
B,
and
5910
B
shall
be
followed
in
accordance
with
Standard
Methods
for
the
Examination
of
Water
and
Wastewater,
19thor
20th
Editions,
American
Public
Health
Association,
1995
and
1998,
respectively.
The
cited
methods
published
in
either
edition
may
be
used.
Standard
Methods
5310
B,
5310
C,
and
5310
D
shall
be
followed
in
accordance
with
the
Supplement
to
the
19th
Edition
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater,
or
the
Standard
Methods
for
the
Examination
of
Water
and
Wastewater,
20th
Edition,
American
Public
Health
Association,
1996
and
1998,
respectively.
The
cited
methods
published
in
either
edition
may
be
used.

Copies
may
be
obtained
from
the
American
Public
Health
Association,
1015
Fifteenth
Street,
NW,

Washington,
DC
20005.
Standard
Methods
4500­
Cl
D­
00,
4500­
Cl
E­
00,
4500­
Cl
F­
00,
4500­
Cl
G­
00,

4500­
Cl
H­
00,
4500­
Cl
I­
00,
4500­
ClO2
E­
00,
6251
B­
94,
5310
B­
00,
5310
C­
00,
5310
D­
00
and
5910
B­
00
are
available
at
http://
www.
standardmethods.
org
or
at
EPA's
Water
Docket.
The
year
in
which
each
293
method
was
approved
by
the
Standard
Methods
Committee
is
designated
by
the
last
two
digits
in
the
method
number.
The
methods
listed
are
the
only
Online
versions
that
are
IBR­
approved.
ASTM
Methods
D
1253­
86
and
D
1253­
86
(
Reapproved
1996)
shall
be
followed
in
accordance
with
the
Annual
Book
of
ASTM
Standards,
Volume
11.01,
American
Society
for
Testing
and
Materials
International,
1996
or
any
ASTM
edition
containing
the
IBR­
approved
version
of
the
method
may
be
used.
ASTM
Method
D1253­

03
shall
be
followed
in
accordance
with
the
Annual
Book
of
ASTM
Standards,
Volume
11.01,
American
Society
for
Testing
and
Materials
International,
2004
or
any
ASTM
edition
containing
the
IBR­
approved
version
of
the
method
may
be
used.
ASTM
Method
D
6581­
00
shall
be
followed
in
accordance
with
the
Annual
Book
of
ASTM
Standards,
Volume
11.01,
American
Society
for
Testing
and
Materials
International,
2001
or
any
ASTM
edition
containing
the
IBR­
approved
version
of
the
method
may
be
used;

copies
may
be
obtained
from
the
American
Society
for
Testing
and
Materials
International,
100
Barr
Harbor
Drive,
West
Conshohocken,
PA
19428­
2959.

(
b)
Disinfection
byproducts.
(
1)
*
*
*

Systems
must
measure
disinfection
byproducts
by
the
methods
(
as
modified
by
the
footnotes)
listed
in
the
following
table:
294
APPROVED
METHODS
FOR
DISINFECTION
BYPRODUCT
COMPLIANCE
MONITORING
Contaminant
and
methodology1
EPA
Method
Standard
Method2
SM
Online9
ASTM
Method3
TTHM
P&
T/
GC/
ElCD
&
PID
502.24
P&
T/
GC/
MS
524.2
LLE/
GC/
ECD
551.1
HAA5
LLE
(
diazomethane)/
GC/
ECD
....................
6251
B5
6251
B­
94
SPE
(
acidic
methanol)/
GC/
ECD
552.15
LLE
(
acidic
methanol)/
GC/
ECD
552.2,
552.3
Bromate
Ion
chromatography
300.1
....................
................
D
6581­
00
Ion
chromatography
&
post
column
reaction
317.0
Rev
2.06,
326.06
IC/
ICP­
MS
321.86,7
Chlorite
Amperometric
titration
.....................
4500­
ClO2
E8
4500­
ClO2
E­
008
................

Spectrophotometry
327.0
Rev
1.18
....................
................
................

Ion
chromatography
300.0,
300.1,
317.0
Rev
2.0,
326.0
....................
................
D
6581­
00
1P&
T
=
purge
and
trap;
GC
=
gas
chromatography;
ElCD
=
electrolytic
conductivity
detector;
PID
=
photoionization
detector;
MS
=
mass
spectrometer;
LLE
=
liquid/
liquid
extraction;
ECD
=
electron
capture
detector;
SPE
=
solid
phase
extraction;
IC
=
ion
chromatography;
ICP­
MS
=
inductively
coupled
plasma/
mass
spectrometer.
219th
and
20th
editions
of
Standard
Methods
for
the
Examination
of
Water
and
Wastewater,
1995
and
1998,
respectively,
American
Public
Health
Association;
either
of
these
editions
may
be
used.
3Annual
Book
of
ASTM
Standards,
2001
or
any
year
containing
the
cited
version
of
the
method,
Vol
11.01.
4If
TTHMs
are
the
only
analytes
being
measured
in
the
sample,
then
a
PID
is
not
required.
5The
samples
must
be
extracted
within
14
days
of
sample
collection.
6
Ion
chromatography
&
post
column
reaction
or
IC/
ICP­
MS
must
be
used
for
monitoring
of
bromate
for
purposes
of
demonstrating
eligibility
of
reduced
monitoring,
as
prescribed
in
§
141.132(
b)(
3)(
ii).
7Samples
must
be
preserved
at
the
time
of
sampling
with
50
mg
ethylenediamine
(
EDA)/
L
of
sample
and
must
be
analyzed
within
28
days.
8Amperometric
titration
or
spectrophotometry
may
be
used
for
routine
daily
monitoring
of
chlorite
at
the
entrance
to
the
distribution
system,
as
prescribed
in
§
141.132(
b)(
2)(
i)(
A).
Ion
chromatography
must
be
used
for
routine
monthly
monitoring
of
chlorite
and
additional
monitoring
of
chlorite
in
the
distribution
system,
as
prescribed
in
§
141.132(
b)(
2)(
i)(
B)
and
(
b)(
2)(
ii).
295
9The
Standard
Methods
Online
version
that
is
approved
is
indicated
by
the
last
two
digits
in
the
method
number
which
is
the
year
of
approval
by
the
Standard
Method
Committee.
Standard
Methods
Online
are
available
at
http://
www.
standardmethods.
org.

(
2)
Analyses
under
this
section
for
disinfection
byproducts
must
be
conducted
by
laboratories
that
have
received
certification
by
EPA
or
the
State,
except
as
specified
under
paragraph
(
b)(
3)
of
this
section.
To
receive
certification
to
conduct
analyses
for
the
DBP
contaminants
in
§
§
141.64,
141.135,
and
subparts
U
and
V
of
this
part,
the
laboratory
must:

(
i)
Analyze
Performance
Evaluation
(
PE)
samples
that
are
acceptable
to
EPA
or
the
State
at
least
once
during
each
consecutive
12
month
period
by
each
method
for
which
the
laboratory
desires
certification.

(
ii)
Until
[
date
one
year
after
date
of
final
rule
publication]
March
31,
2007,
in
these
analyses
of
PE
samples,
the
laboratory
must
achieve
quantitative
results
within
the
acceptance
limit
on
a
minimum
of
80%

of
the
analytes
included
in
each
PE
sample.
The
acceptance
limit
is
defined
as
the
95%
confidence
interval
calculated
around
the
mean
of
the
PE
study
between
a
maximum
and
minimum
acceptance
limit
of
+/­
50%

and
+/­
15%
of
the
study
mean.

(
iii)
Beginning
[
date
one
year
after
date
of
final
rule
publication],
April
1,
2007,
the
laboratory
must
achieve
quantitative
results
on
the
PE
sample
analyses
that
are
within
the
following
acceptance
limits:

DBP
Acceptance
Limits
(
percent
of
true
value)
Comments
TTHM
Chloroform
Bromodichloromethane
Dibromochloromethane
Bromoform
±
20
±
20
±
20
±
20
Laboratory
must
meet
all
4
individual
THM
acceptance
limits
in
order
to
successfully
pass
a
PE
sample
for
TTHM
HAA5
Monochloroacetic
Acid
Dichloroacetic
Acid
Trichloroacetic
Acid
Monobromoacetic
Acid
Dibromoacetic
Acid
±
40
±
40
±
40
±
40
±
40
Laboratory
must
meet
the
acceptance
limits
for
4
out
of
5
of
the
HAA5
compounds
in
order
to
successfully
pass
a
PE
sample
for
HAA5
Chlorite
±
30
Bromate
±
30
(
iv)
Beginning
[
date
one
year
after
date
of
final
rule
publication]
April
1,
2007,
report
quantitative
data
for
296
concentrations
at
least
as
low
as
the
ones
listed
in
the
following
table
for
all
DBP
samples
analyzed
for
compliance
with
§
§
141.64,
141.135,
and
subparts
U
and
V
of
this
part:

DBP
Minimum
reporting
level
(
mg/
L)
1
Comments
TTHM
2
Chloroform
Bromodichloromethane
Dibromochloromethane
Bromoform
0.0010
0.0010
0.0010
0.0010
HAA5
2
Monochloroacetic
Acid
Dichloroacetic
Acid
Trichloroacetic
Acid
Monobromoacetic
Acid
Dibromoacetic
Acid
0.0020
0.0010
0.0010
0.0010
0.0010
Chlorite
0.020
Applicable
to
monitoring
as
prescribed
in
§
141.132(
b)(
2)(
i1)(
B)
and
(
b)(
2)(
ii).

Bromate
0.0050
or
0.0010
Laboratories
that
use
EPA
Methods
317.0
Revision
2.0,
326.0
or
321.8
must
meet
a
0.0010
mg/
L
MRL
for
bromate.

1
The
calibration
curve
must
encompass
the
regulatory
minimum
reporting
level
(
MRL)
concentration.
Data
may
be
reported
for
concentrations
lower
than
the
regulatory
MRL
as
long
as
the
precision
and
accuracy
criteria
are
met
by
analyzing
an
MRL
check
standard
at
the
lowest
reporting
limit
chosen
by
the
laboratory.
The
laboratory
must
verify
the
accuracy
of
the
calibration
curve
at
the
MRL
concentration
by
analyzing
an
MRL
check
standard
with
a
concentration
less
than
or
equal
to
110%
of
the
MRL
with
each
batch
of
samples.
The
measured
concentration
for
the
MRL
check
standard
must
be
±
50%
of
the
expected
value,
if
any
field
sample
in
the
batch
has
a
concentration
less
than
5
times
the
regulatory
MRL.
Method
requirements
to
analyze
higher
concentration
check
standards
and
meet
tighter
acceptance
criteria
for
them
must
be
met
in
addition
to
the
MRL
check
standard
requirement.
2
When
adding
the
individual
trihalomethane
or
haloacetic
acid
concentrations
to
calculate
the
TTHM
or
HAA5
concentrations,
respectively,
a
zero
is
used
for
any
analytical
result
that
is
less
than
the
MRL
concentration
for
that
DBP,
unless
otherwise
specified
by
the
State.

(
3)
*
*
*

*
*
*
*
*

*
*
*
*
*

(
c)
***
297
(
1)
***

Methodology
SM
(
19th
or
20th
ed)
SM
Online2
ASTM
method
EPA
method
Residual
Measured1
Free
Cl2
Combined
Cl2
Total
Cl2
ClO2
Amperometric
Titration
4500­
Cl
D
4500­
Cl
D­
00
D
1253­
86
(
96),
03
X
X
X
Low
Level
Amperometric
Titration
4500­
Cl
E
4500­
Cl
E­
00
X
DPD
Ferrous
Titrimetric
4500­
Cl
F
4500­
Cl
F­
00
X
X
X
DPD
Colorimetric
4500­
Cl
G
4500­
Cl
G­
00
X
X
X
Syringaldazine
(
FACTS)
4500­
Cl
H
4500­
Cl
H­
00
X
Iodometric
Electrode
4500­
Cl
I
4500­
Cl
I­
00
X
DPD
4500­
ClO2
D
X
Amperometric
Method
II
4500­
ClO2
E
4500­
ClO2
E­
00
X
Lissamine
Green
Spectrophotometric
327.0
Rev
1.1
X
1
X
indicates
method
is
approved
for
measuring
specified
disinfectant
residual.
Free
chlorine
or
total
chlorine
may
be
measured
for
demonstrating
compliance
with
the
chlorine
MRDL
and
combined
chlorine
or
total
chlorine
may
be
measured
for
demonstrating
compliance
with
the
chloramine
MRDL.
2The
Standard
Methods
Online
version
that
is
approved
is
indicated
by
the
last
two
digits
in
the
method
number
which
is
the
year
of
approval
by
the
Standard
Method
Committee.
Standard
Methods
Online
are
available
at
http://
www.
standardmethods.
org.

*
*
*
*
*

(
d)
***

(
2)
Bromide.
EPA
Methods
300.0,
300.1,
317.0
Revision
2.0,
326.0,
or
ASTM
D
6581­
00.

(
3)
Total
Organic
Carbon
(
TOC).
Standard
Method
5310
B
or
5310
B­
00
(
High­
Temperature
Combustion
Method)
or
Standard
Method
5310
C
or
5310
C­
00
(
Persulfate­
Ultraviolet
or
298
Heated­
Persulfate
Oxidation
Method)
or
Standard
Method
5310
D
or
5310
D­
00
(
Wet­
Oxidation
Method)

or
EPA
Method
415.3
Revision
1.1.
Inorganic
carbon
must
be
removed
from
the
samples
prior
to
analysis.

TOC
samples
may
not
be
filtered
prior
to
analysis.
TOC
samples
must
be
acidified
at
the
time
of
sample
collection
to
achieve
pH
less
than
or
equal
to
2
with
minimal
addition
of
the
acid
specified
in
the
method
or
by
the
instrument
manufacturer.
Acidified
TOC
samples
must
be
analyzed
within
28
days.

(
4)
***

(
i)
Dissolved
Organic
Carbon
(
DOC).
Standard
Method
5310
B
or
5310
B­
00
(
High­
Temperature
Combustion
Method)
or
Standard
Method
5310
C
or
5310
C­
00
(
Persulfate­
Ultraviolet
or
Heated­
Persulfate
Oxidation
Method)
or
Standard
Method
5310
D
or
5310
D­
00
(
Wet­
Oxidation
Method)

or
EPA
Method
415.3
Revision
1.1.
DOC
samples
must
be
filtered
through
the
0.45
µ
m
pore­
diameter
filter
as
soon
as
practical
after
sampling,
not
to
exceed
48
hours.
After
filtration,
DOC
samples
must
be
acidified
to
achieve
pH
less
than
or
equal
to
2
with
minimal
addition
of
the
acid
specified
in
the
method
or
by
the
instrument
manufacturer.
Acidified
DOC
samples
must
be
analyzed
within
28
days
of
sample
collection.
Inorganic
carbon
must
be
removed
from
the
samples
prior
to
analysis.
Water
passed
through
the
filter
prior
to
filtration
of
the
sample
must
serve
as
the
filtered
blank.
This
filtered
blank
must
be
analyzed
using
procedures
identical
to
those
used
for
analysis
of
the
samples
and
must
meet
the
following
criteria:
DOC
<
0.5
mg/
L.

(
ii)
Ultraviolet
Absorption
at
254
nm
(
UV254).
Standard
Method
5910
B
or
5910
B­
00
(
Ultraviolet
Absorption
Method)
or
EPA
Method
415.3
Revision
1.1.
UV
absorption
must
be
measured
at
253.7
nm
(
may
be
rounded
off
to
254
nm).
Prior
to
analysis,
UV254
samples
must
be
filtered
through
a
0.45
µ
m
pore­
diameter
filter.
The
pH
of
UV254
samples
may
not
be
adjusted.
Samples
must
be
analyzed
as
soon
as
practical
after
sampling,
not
to
exceed
48
hours.

*
*
*
*
*

(
6)
Magnesium.
All
methods
allowed
in
§
141.23(
k)(
1)
for
measuring
magnesium.
299
12.
Section
141.132
is
amended
by:

a.
redesignating
paragraphs
(
b)(
1)(
iii)
through
(
b)(
1)(
v)
as
paragraphs
(
b)(
1)(
iv)
through
(
b)(
1)(
vi),

b.
adding
a
new
paragraph
(
b)(
1)(
iii),
and
ac.
adding
the
following
sentence
as
the
first
sentence
to
the
currentnewly
redesignated
paragraph
(
b)(
1)(
iii),

b.
redesignating
paragraphs
(
b)(
1)(
iii)
through
(
b)(
1)(
v)
as
paragraphs
(
b)(
1)(
iv)
through
(
b)(
1)(
vi)
and
adding
a
new
paragraph
(
b)(
1)(
iii),
and
c.
removing
paragraph
(
b)(
3)(
ii)
and
adding
in
its
place
the
following
paragraph:

iv)
to
read
as
follows:

§
141.132
Monitoring
requirements.

*
*
*
*
*

(
b)
*
*
*

(
1)
*
*
*

(
i)
*
*
*

(
ii)
*
*
*

(
iii)
Monitoring
requirements
for
source
water
TOC.
In
order
to
qualify
for
reduced
monitoring
for
TTHM
and
HAA5
under
paragraph
(
b)(
1)(
ii)
of
this
section,
subpart
H
systems
not
monitoring
under
the
provisions
of
paragraph
(
d)
of
this
section
must
take
monthly
TOC
samples
every
30
days
at
a
location
prior
to
any
treatment,
beginning
April
1,
2008
or
earlier,
if
specified
by
the
State.
In
addition
to
meeting
other
criteria
for
reduced
monitoring
in
paragraph
(
b)(
1)(
ii)
of
this
section,
the
source
water
TOC
running
annual
average
must
be
#
4.0
mg/
L
(
based
on
the
most
recent
four
quarters
of
monitoring)
on
a
continuing
basis
at
each
treatment
plant
to
reduce
or
remain
on
reduced
monitoring
for
TTHM
and
HAA5.
Once
qualified
for
reduced
monitoring
for
TTHM
and
HAA5
under
paragraph
(
b)(
1)(
ii)
of
this
section,
a
system
may
reduce
source
water
TOC
monitoring
to
quarterly
TOC
samples
taken
every
90
days
at
a
location
300
prior
to
any
treatment.

(
iv)
Systems
on
a
reduced
monitoring
schedule
may
remain
on
that
reduced
schedule
as
long
as
the
average
of
all
samples
taken
in
the
year
(
for
systems
which
must
monitor
quarterly)
or
the
result
of
the
sample
(
for
systems
which
must
monitor
no
more
than
frequently
than
annually)
is
no
more
than
0.060
mg/
L
and
0.045
mg/
L
for
TTHMs
and
HAA5,
respectively.
Systems
that
do
not
meet
these
levels
must
resume
monitoring
at
the
frequency
identified
in
paragraph
(
b)(
1)(
i)
of
this
section
(
minimum
monitoring
frequency
column)
in
the
quarter
immediately
following
the
monitoring
period
in
which
the
system
exceeds
0.060
mg/
L
or
0.045
mg/
L
for
TTHMs
and
HAA5,
respectively.
For
systems
using
only
ground
water
not
under
the
direct
influence
of
surface
water
and
serving
fewer
than
10,000
persons,
if
either
the
TTHM
annual
average
is
>
0.080
mg/
L
or
the
HAA5
annual
average
is
>
0.060
mg/
L,
the
system
must
go
to
the
increased
monitoring
identified
in
paragraph
(
b)(
1)(
i)
of
this
section
(
sample
location
column)
in
the
quarter
immediately
following
the
monitoring
period
in
which
the
system
exceeds
0.80080
mg/
L
or
0.060
mg/
L
for
TTHMs
or
HAA5
respectively.

(
v)
Systems
on
increased
monitoring
may
return
to
routine
monitoring
if,
after
at
least
one
year
of
monitoring
their
TTHM
annual
average
is
<
0.060
mg/
L
and
their
HAA5
annual
average
is
<
0.045mg/
L.

(
vi)
The
State
may
return
a
system
to
routine
monitoring
at
the
State's
discretion.

*
*
*
*
*

(
3)
***

(
i)
***

(
ii)
Reduced
monitoring.

(
A)
Until
[
date
three
years
from
final
rule
publication]
March
31,
2009,
systems
required
to
analyze
for
bromate
may
reduce
monitoring
from
monthly
to
quarterly,
if
the
system's
average
source
water
bromide
concentration
is
less
than
0.05
mg/
L
based
on
representative
monthly
bromide
measurements
for
one
year.

The
system
may
remain
on
reduced
bromate
monitoring
until
the
running
annual
average
source
water
bromide
concentration,
computed
quarterly,
is
equal
to
or
greater
than
0.05
mg/
L
based
on
representative
301
monthly
measurements.
If
the
running
annual
average
source
water
bromide
concentration
is
$
0.05
mg/
L,

the
system
must
resume
routine
monitoring
required
by
paragraph
(
b)(
3)(
i)
of
this
section
in
the
following
month.

(
B)
Beginning
[
date
three
years
from
final
rule
publication]
April
1,
2009,
systems
may
no
longer
use
the
provisions
of
paragraph
(
b)(
3)(
ii)(
A)
of
this
section
to
qualify
for
reduced
monitoring.
A
system
required
to
analyze
for
bromate
may
reduce
monitoring
from
monthly
to
quarterly,
if
the
system's
running
annual
average
bromate
concentration
is
#
0.0025
mg/
L
based
on
monthly
bromate
measurements
under
paragraph
(
b)(
3)(
i)
of
this
section
for
the
most
recent
four
quarters,
with
samples
analyzed
using
Method
317.0
Revision
2.0,
326.0
or
321.8.
If
a
system
has
qualified
for
reduced
bromate
monitoring
under
paragraph
(
b)(
3)(
ii)(
A)
of
this
section,
that
system
may
remain
on
reduced
monitoring
as
long
as
the
running
annual
average
of
quarterly
bromate
samples
#
0.0025
mg/
L
based
on
samples
analyzed
using
Method
317.0
Revision
2.0,
326.0,
or
321.8.
If
the
running
annual
average
bromate
concentration
is
>
0.0025
mg/
L,
the
system
must
resume
routine
monitoring
required
by
paragraph
(
b)(
3)(
i)
of
this
section.

*
*
*
*
*

§
141.133
­
[
AMENDED]

13.
Section
141.133(
d)
is
amended
by
revisingin
the
last
sentence
by
replacing
"
§
141.32"
and
add
in
its
place
"
subpart
Q".

§
141.135
[
AMENDED]
of
paragraph
(
d)
by
revising
the
reference
"
§
141.32"
to
read
"
subpart
Q
of
this
part".

14.
Section
141.135
is
amended
by
revising
paragraph
(
a)(
3)(
ii)
by
adding
the
phrase
"
according
to
§
141.131(
d)(
6)"
to
read
as
follows:
302
§
141.135
Treatment
technique
for
control
of
disinfection
byproduct
(
DBP)
precursors.

(
a)
*
*
*

(
3)
*
*
*

(
ii)
Softening
that
results
in
removing
at
least
10
mg/
L
of
magnesium
hardness
(
as
CaCO3),
measured
monthly
according
to
§
141.131(
d)(
6)
and
calculated
quarterly
as
a
running
annual
average.

*
*
*
*
*

Subpart
O
­
[
amended]

15.
Section
141.151
is
amended
by
revising
paragraph
(
d)
to
read
as
follows:

§
141.151
Purpose
and
applicability
of
this
subpart.

*
*
*
*
*

(
d)
For
the
purpose
of
this
subpart,
detected
means:
at
or
above
the
levels
prescribed
by
§
141.23(
a)(
4)
for
inorganic
contaminants,
at
or
above
the
levels
prescribed
by
§
141.24(
f)(
7)
for
the
contaminants
listed
in
§
141.61(
a),
at
or
above
the
levels
prescribed
by
§
141.24(
h)(
18)
for
the
contaminants
listed
in
§
141.61(
c),

at
or
above
the
levels
prescribed
by
§
141.131(
b)(
2)(
iv)
for
the
contaminants
or
contaminant
groups
listed
in
§
141.64,
and
at
or
above
the
levels
prescribed
by
§
141.25(
c)
for
radioactive
contaminants.

*
*
*
*
*

16.
Section
141.153
is
amended
by
removingrevising
paragraphs
(
d)(
4)(
iv)(
B)
and
(
d)(
4)(
iv)(
C)
and
adding
two
paragraphs
in
their
place
to
read
as
follows:

§
141.153
Content
of
the
reports.

*
*
*
*
*

(
d)
*
*
*

(
4)
*
*
*

(
iv)
*
*
*
303
(
A)
*
*
*

(
B)
When
compliance
with
the
MCL
is
determined
by
calculating
a
running
annual
average
of
all
samples
taken
at
a
monitoring
location:
the
highest
average
of
any
of
the
monitoring
locations
and
the
range
of
all
monitoring
locations
expressed
in
the
same
units
as
the
MCL.
For
the
MCLs
for
TTHM
and
HAA5
in
§
141.64(
b)(
2),
systems
must
include
the
highest
locational
running
annual
average
for
TTHM
and
HAA5
and
the
range
of
individual
sample
results
for
all
monitoring
locations
expressed
in
the
same
units
as
the
MCL.
If
more
than
one
location
exceeds
the
TTHM
or
HAA5
MCL,
the
system
must
include
the
locational
running
annual
averages
for
all
locations
that
exceed
the
MCL.

(
C)
When
compliance
with
the
MCL
is
determined
on
a
system­
wide
basis
by
calculating
a
running
annual
average
of
all
samples
at
all
monitoring
locations:
the
average
and
range
of
detection
expressed
in
the
same
units
as
the
MCL.
The
system
is
required
to
include
the
range
of
individual
sample
results
for
the
IDSE
conducted
under
subpart
U
asof
this
part
ofwhen
determining
the
range
of
TTHM
and
HAA5
results
to
be
reported
in
the
annual
consumer
confidence
report
for
the
calendar
year
that
the
IDSE
samples
were
taken.
***

*
*
*
*
*

17.
In
Subpart
Q,
Appendix
A
is
amended
as
follows:

a.
a.
In
entry
I.
B.
2.
in
the
fifth
column,
remove
the
endnote
citation
"
9"
and
add
in
its
place
"
11";

b.
In
entry
I.
B.
11.
in
the
fourth
column,
remove
the
endnote
citation
"
10"
and
add
in
its
place
"
12";

c.
In
entry
I.
B.
12.
in
the
fourth
column,
remove
the
endnote
citation
"
10"
and
add
in
its
place
"
12";

d.
In
entry
I.
G.
in
the
first
column,
remove
the
endnote
citation
"
11"
and
add
in
its
place
"
13";
304
e.
In
entry
I.
G.
1.
in
the
third
column,
remove
the
endnote
citation
"
12"
and
add
in
its
place
"
14"
and
remove
the
citation
in
the
third
column
"
141.12,141.64(
a)"
and
in
its
place
add
"
141.64(
b)"
(
keeping
the
endnote
citation
to
endnote
14)
and
in
the
fifth
column
remove
the
citation
"
141.30"
and
add
in
numerical
order
the
citations
"
141.600­
141.605,
141.620­
141.629",

and;

b
f.
In
entry
I.
G.
2.
revise
the
entry
"
141.64(
a)"
to
read
"
141.64(
b)"
and
in
the
fifth
column
add
in
numerical
order
the
citations
"
141.600­
141.605,
141.620­
141.629".

g.
In
entry
I.
G.
7.
in
the
fourth
column,
remove
the
endnote
citation
"
13"
and
add
in
its
place
"
15";

h.
In
entry
I.
G.
8.
in
the
second
column,
remove
the
endnote
citation
"
14"
and
add
in
its
place
"
16";

i.
In
entry
II.
in
the
first
column,
remove
the
endnote
citation
"
15"
and
add
in
its
place
"
17";

j.
In
entry
III.
A.
in
the
third
column,
remove
the
endnote
citation
"
16"
and
add
in
its
place
"
18";

k.
In
entry
III.
B
in
the
third
column,
remove
the
endnote
citation
"
17"
and
add
in
its
place
"
19";

l.
In
entry
IV.
E.
in
the
first
column,
remove
the
endnote
citation
"
18"
and
add
in
its
place
20";
and
m.
In
entry
III.
F
in
the
second
column,
remove
the
endnote
citation
"
19"
and
add
in
its
place
"
21".

18.
In
Subpart
Q,
Appendix
A,
remove
endnote14
and
add
in
its
place,
to
read
as
follows:
"
14.

§
§
141.64(
b)(
1)
and
141.132(
a)­(
b)
apply
until
§
§
141.620­
141.630
take
effect
under
the
schedule
305
in
§
141.620(
c).

19.
In
Subpart
Q,
Appendix
B
is
amended
in
entry
H.
80,
as
follows:

a.
In
entry
G.
77.
in
the
third
column,
remove
the
endnote
citation
"
16"
and
add
in
its
place
"
17";

b.
In
entry
H.
(
the
title)
in
the
first
column,
remove
the
endnote
citation
"
17"
and
add
in
its
place
"
18";

c.
In
entry
H.
80.
in
the
third
column,
remove
the
endnote
citations
"
17,
18"
and
add
in
its
place
"
19,
20"
and
remove
the
number
"
0.10/";

d.
In
entry
H.
81.
in
the
third
column,
remove
the
endnote
citation
"
20"
and
add
in
its
place
"
21";
and
e.
In
entry
H.
84.
in
the
second
column,
remove
the
endnote
citation
"
21"
and
add
in
its
place
"
22"
and
in
the
third
column
by
removingremove
the
number
"
0.10/"
endnote
citation
"
22"

and
add
in
its
place
"
23".

20.
In
Subpart
Q,
Appendix
B,
remove
endnotes
18
and
19
and
add
in
their
place,
to
read
as
follows:
"
18.

Surface
water
systems
and
ground
water
systems
under
the
direct
influence
of
surface
water
are
regulated
under
subpart
H
of
40
CFR
141.
Subpart
H
community
and
non­
transient
non­
community
systems
serving
$
10,000
must
comply
with
subpart
L
DBP
MCLs
and
disinfectant
maximum
residual
disinfectant
levels
(
MRDLs)
beginning
January
1,
2002.
All
other
community
and
non­
transient
non­
community
systems
must
comply
with
subpart
L
DBP
MCLs
and
disinfectant
MRDLs
beginning
January
1,
2004.
Subpart
H
transient
non­
community
systems
serving
$
10,000
that
use
chlorine
dioxide
as
a
disinfectant
or
oxidant
must
comply
with
the
chlorine
dioxide
MRDL
beginning
January
1,
2002.
All
other
transient
noncommunity
systems
that
use
chlorine
dioxide
as
a
disinfectant
or
oxidant
must
comply
with
the
chlorine
306
dioxide
MRDL
beginning
January
1,
2004.

19.
Community
and
non­
transient
non­
community
systems
must
comply
with
subpart
V
TTHM
and
HAA5
MCLs
of
0.080
mg/
L
and
0.060
mg/
L,
respectively
(
with
compliance
calculated
as
a
locational
running
annual
average)
on
the
schedule
in
§
141.620."

21.
Part
141
is
amended
by
adding
new
subpart
U
to
read
as
follows:

Subpart
U­
Initial
Distribution
System
Evaluations
Sec.

141.600
General
requirements.

141.601
Standard
monitoring.

141.602
System
specific
studies.

141.603
40/
30
certification.

141.604
Very
small
system
waivers.

141.605
Subpart
V
monitoring
location
recommendations.

Subpart
U­
Initial
Distribution
System
Evaluations
§
141.600
General
requirements.

(
a)
The
requirements
of
subpart
U
of
this
part
constitute
national
primary
drinking
water
regulations.
The
regulations
in
this
subpart
establish
monitoring
and
other
requirements
for
identifying
subpart
V
compliance
monitoring
locations
for
determining
compliance
with
maximum
contaminant
levels
for
total
trihalomethanes
(
TTHM)
and
haloacetic
acids
(
five)(
HAA5).
You
willmust
use
an
Initial
Distribution
System
Evaluation
(
IDSE)
to
determine
locations
with
representative
high
TTHM
and
HAA5
concentrations
throughout
your
distribution
system.
IDSEs
are
used
in
conjunction
with,
but
separate
from,
subpart
L
compliance
monitoring,
to
identify
and
select
subpart
V
compliance
monitoring
locations.

(
b)
Applicability.
You
are
subject
to
these
requirements
if
your
system
is
a
community
water
system
that
uses
a
primary
or
residual
disinfectant
other
than
ultraviolet
light
or
delivers
water
that
has
been
treated
307
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
light;
or
if
your
system
is
a
nontransient
noncommunity
water
system
that
serves
at
least
10,000
people
and
uses
a
primary
or
residual
disinfectant
other
than
ultraviolet
light
or
delivers
water
that
has
been
treated
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
light.

(
c)
Schedule.
(
1)
You
must
comply
with
the
requirements
of
this
subpart
on
the
schedule
in
the
table
in
this
paragraph
(
c)(
1).
308
IF
YOU
SERVE
THIS
POPULATION
YOU
MUST
SUBMIT
YOUR
STANDARD
MONITORING
PLAN/
SYSTEMPLAN
OR
SYSTEM
SPECIFIC
STUDY
PLAN
1
OR
40/
30
CERTIFICATION2
TO
THE
STATE
BY
OR
RECEIVE
VERY
SMALL
SYSTEM
WAIVER
FROM
STATE
YOU
MUST
COMPLETE
YOUR
STANDARD
MONITORING
OR
SYSTEM
SPECIFIC
STUDY
BY
YOU
MUST
SUBMIT
YOUR
IDSE
REPORT
TO
THE
STATE
BY
3
Systems
that
are
not
part
of
a
combined
distribution
system
and
systems
that
serve
the
largest
population
in
the
combined
distribution
system
(
i)
$
100,000
[
date
six
mos
following
publication
of
final
rule][
date
30
mos
following
publication
of
final
rule][
date
33
mos
following
publication
of
final
rule]
October
1,
2006
September
30,
2008
January
1,
2009
(
ii)
50,000­

99,999
[
date
12
mos
following
publication
of
final
rule][
date
36
mos
following
publication
of
final
rule][
date
39
mos
following
publication
of
final
rule]
April
1,
2007
March
31,
2009
July
1,
2009
(
iii)
10,000­

49,999
[
date
18
mos
following
publication
of
final
rule][
date
42
mos
following
publication
of
final
rule][
date
45
mos
following
publication
of
final
rule]
October
1,
2007
September
30,
2009
January
1,
2010
(
iv)
<
10,000
(
CWS
Only)
[
date
24
mos
following
publication
of
final
rule]
[
date
48
mos
following
publication
of
final
rule]
[
date
51
mos
following
publication
of
final
rule]
April
1,
2008
March
31,
2010
July
1,
2010
Other
systems
that
are
part
of
a
combined
distribution
system
(
v)
Wholesale
system
or
consecutive
­
at
the
same
time
as
the
system
with
the
earliest
compliance
date
in
the
combined
distribution
system
­
at
the
same
time
as
the
system
with
the
earliest
compliance
date
in
the
combined
distribution
system
­
at
the
same
time
as
the
system
with
the
earliest
compliance
date
in
the
combined
distribution
system
309
1
If
the
State
does
not
approve
or
modify
your
plan,
within
12
months
after
the
date
identified
in
this
column,
the
State
does
not
approve
your
plan
or
notify
you
that
it
has
not
yet
completed
its
review,
you
may
consider
the
plan
that
you
submitted
as
approved
and.
You
must
implement
that
plan
so
thatand
you
must
complete
standard
monitoring
or
a
system
specific
study
no
later
than
the
date
identified
in
the
third
column.

2
You
must
submit
your
40/
30
certification
under
§
141.603
by
the
date
indicated.
If
you
fail
to
submit
your
certification
by
the
date
indicated,
even
if
you
otherwise
qualify
for
40/
30
certification,
you
must
conduct
either
standard
monitoring
or
a
system
specific
study.

3
If
the
State
does
not
approve
or
modify
your
IDSE
report,
within
three
months
after
the
date
identified
in
this
column
(
nine
months
after
the
date
identified
in
this
column
if
you
must
comply
on
the
schedule
in
paragraph
(
c)(
1)(
iii)
of
this
section),
the
State
does
not
approve
your
IDSE
report
or
notify
you
that
it
has
not
yet
completed
its
review,
you
may
consider
the
report
that
you
submitted
as
approved
and
you
must
implement
the
recommended
subpart
V
monitoring
as
required.
310
(
2)
For
the
purpose
of
the
schedule
in
paragraph
(
c)(
1)
of
this
section,
the
State
may
determine
that
the
combined
distribution
system
does
not
include
certain
consecutive
systems
based
on
factors
such
as
receiving
water
from
a
wholesale
system
only
on
an
emergency
basis
or
receiving
only
a
small
percentage
and
small
volume
of
water
from
a
wholesale
system.
The
State
may
also
determine
that
the
combined
distribution
system
does
not
include
certain
wholesale
systems
based
on
factors
such
as
delivering
water
to
a
consecutive
system
only
on
an
emergency
basis
or
delivering
only
a
small
percentage
and
small
volume
of
water
to
a
consecutive
system.

(
d)
You
must
conduct
standard
monitoring
that
meets
the
requirements
in
§
141.601,
or
a
system
specific
study
that
meets
the
requirements
in
§
141.602,
or
certify
to
the
State
that
you
meet
40/
30
certification
criteria
under
§
141.603,
or
qualify
for
a
very
small
system
waiver
under
§
141.604.

(
1)
You
must
have
taken
the
full
complement
of
routine
TTHM
and
HAA5
compliance
samples
required
of
a
system
with
your
population
and
source
water
under
subpart
L
of
this
part
(
or
you
must
have
taken
the
full
complement
of
reduced
TTHM
and
HAA5
compliance
samples
required
of
a
system
with
your
population
and
source
water
under
subpart
L
if
you
meet
reduced
monitoring
criteria
under
subpart
L
of
this
part)
during
the
two
year
period
specified
in
§
141.603(
a)
to
meet
the
40/
30
certification
criteria
in
§
141.603.
You
must
have
taken
TTHM
and
HAA5
samples
under
§
§
141.131
and
141.132
to
be
eligible
for
the
very
small
system
waiver
in
§
141.604.

(
2)
If
you
have
not
taken
the
required
samples,
you
must
conduct
standard
monitoring
that
meets
the
requirements
in
§
141.601,
or
a
system
specific
study
that
meets
the
requirements
in
§
141.602.

(
e)
You
must
use
only
the
analytical
methods
specified
in
§
141.131,
or
otherwise
approved
by
EPA
for
monitoring
under
this
subpart,
to
demonstrate
compliance
with
the
requirements
of
this
subpart.

(
f)
IDSE
results
will
not
be
used
for
the
purpose
of
determining
compliance
with
MCLs
in
§
141.64.

§
141.601
Standard
monitoring.

(
a)
Standard
monitoring
plan.
Your
standard
monitoring
plan
must
comply
with
paragraphs
(
a)(
1)
311
through
(
a)(
4)
of
this
section.
You
must
prepare
and
submit
your
standard
monitoring
plan
to
the
State
according
to
the
schedule
in
§
141.600(
c).

(
1)
Your
standard
monitoring
plan
must
include
a
schematic
of
your
distribution
system
(
including
distribution
system
entry
points
and
their
sources,
and
storage
facilities),
with
notes
indicating
locations
and
dates
of
all
projected
standard
monitoring,
and
all
projected
subpart
L
compliance
monitoring
noted.

(
2)
Your
standard
monitoring
plan
must
include
justification
of
standard
monitoring
location
selection
and
all
additional
summary
of
data
you
relied
on
to
justify
standard
monitoring
location
selection.

(
3)
Your
standard
monitoring
plan
must
specify
the
population
served
and
system
type
(
subpart
H
or
ground
water).

(
4)
You
must
retain
a
complete
copy
of
your
standard
monitoring
plan
submitted
under
this
paragraph
(
a),

including
any
State
modification
of
your
standard
monitoring
plan,
for
as
long
as
you
are
required
to
retain
your
IDSE
report
under
paragraph
(
c)(
4)
of
this
section.

(
b)
Standard
monitoring.
(
1)
You
must
monitor
as
indicated
in
the
table
in
this
paragraph
(
b)(
1).
You
must
collect
dual
sample
sets
at
each
monitoring
location.
One
sample
in
the
dual
sample
set
must
be
analyzed
for
TTHM.
The
other
sample
in
the
dual
sample
set
must
be
analyzed
for
HAA5.
You
must
conduct
one
monitoring
period
during
the
peak
historical
month
for
TTHM
levels
or
HAA5
levels
or
the
month
of
warmest
water
temperature.
You
must
review
available
compliance,
study,
or
operational
data
to
determine
the
peak
historical
month
for
TTHM
or
HAA5
levels
or
warmest
water
temperature.
312
Source
Water
Type
Population
Size
Category
Monitoring
Periods
and
Frequency
of
Sampling
Distribution
System
Monitoring
Locations1
Total
per
monitoring
period
Near
Entry
Points
Average
Residence
Time
High
TTHM
Locations
High
HAA5
Locations
Subpart
H
<
500
consecutive
systems
one
(
during
peak
historical
month)
2213
2
1
!
1
!

<
500
nonconsecutive
systems
2
!
!
1
1
500­
3,300
consecutive
systems
four
(
every
90
days)
2
1
!
1
!

500­
3,300
nonconsecutive
systems
2
!
!
1
141
3,301­
9,999
4
!
1
2
1
10,000­
49,999
six
(
every
60
days)
8
1
2
3
2
50,000­
249,999
16
3
4
5
4
250,000­
999,999
24
4
6
8
6
1,000,000­
4,999,999
32
6
8
10
8
$
5,000,000
40
8
10
12
10
Ground
Water
<
500
consecutive
systems
one
(
during
peak
historical
month)
2
2
13
1
!
1
!

<
500
nonconsecutive
systems
2
!
!
1
1
500­
9,999
four
(
every
90
days)
2
!
!
1
141
10,000­
99,999
6
1
1
2
2
100,000­
499,999
8
1
1
3
3
$
500,000
12
2
2
4
4
1
A
dual
sample
set
(
i.
e.,
a
TTHM
and
an
HAA5
sample)
must
be
taken
at
each
monitoring
location
during
each
monitoring
period.
2
The
peak
historical
month
is
the
month
with
the
highest
TTHM
or
HAA5
levels
or
the
warmest
water
temperature.
3
You
must
monitor
at
or
near
the
entry
point
if
you
are
a
consecutive
system.
If
you
are
not
a
consecutive
system,
you
must
monitor
at
a
high
HAA5
location.
4
You
must
monitor
at
or
near
the
entry
point
if
you
are
a
consecutive
system.

(
2)
You
must
take
samples
at
locations
other
than
the
existing
subpart
L
monitoring
locations.

Monitoring
locations
must
be
distributed
throughout
the
distribution
system.

(
3)
If
the
number
of
entry
points
to
the
distribution
system
is
fewer
than
the
specified
number
of
entry
313
point
monitoring
locations,
excess
entry
point
samples
must
be
replaced
equally
at
high
TTHM
and
HAA5
locations.
If
there
is
an
odd
extra
location
number,
you
must
take
a
sample
at
a
high
TTHM
location.
If
the
number
of
entry
points
to
the
distribution
system
is
more
than
the
specified
number
of
entry
point
monitoring
locations,
you
must
take
samples
at
entry
points
to
the
distribution
system
having
the
highest
annual
water
flows.

(
4)
Your
monitoring
under
this
paragraph
(
b)
may
not
be
reduced
under
the
provisions
of
§
141.29
and
the
State
may
not
reduce
your
monitoring
using
the
provisions
of
§
142.16(
m).

(
c)
IDSE
report.
Your
IDSE
report
must
include
the
elements
required
in
paragraphs
(
c)(
1)
through
(
c)(
4)
of
this
section.
You
must
submit
your
IDSE
report
to
the
State
according
to
the
schedule
in
§
141.600(
c).

(
1)
Your
IDSE
report
must
include
all
TTHM
and
HAA5
analytical
results
and
LRAAs
from
subpart
L
compliance
monitoring
and
all
standard
monitoring
conducted
during
the
period
of
the
IDSE
as
individual
analytical
results
and
LRAAs
presented
in
a
tabular
or
spreadsheet
format
acceptable
to
the
State.
If
changed
from
your
standard
monitoring
plan
submitted
under
paragraph
(
a)
of
this
section,
your
report
must
also
include
a
schematic
of
your
distribution
system,
the
population
served,
and
system
type
(
subpart
H
or
ground
water).

(
2)
Your
IDSE
report
must
include
an
explanation
of
any
deviations
from
your
approved
standard
monitoring
plan.

(
3)
You
must
recommend
and
justify
subpart
V
compliance
monitoring
locations
and
timing
based
on
the
protocol
in
§
141.605.

(
4)
You
must
retain
a
complete
copy
of
your
IDSE
report
submitted
under
this
section
for
10
years
after
the
date
that
you
submitted
your
report.
If
the
State
modifies
the
subpart
V
monitoring
requirements
that
you
recommended
in
your
IDSE
report
or
if
the
State
approves
alternative
monitoring
locations,
you
must
keep
a
copy
of
the
State's
notification
on
file
for
10
years
after
the
date
of
the
State's
notification.
You
must
make
the
IDSE
report
and
any
State
notification
available
for
review
by
the
State
or
the
public.
314
§
141.602
System
specific
studies.

(
a)
System
specific
study
plan.
Your
system
specific
study
plan
must
be
based
on
either
existing
monitoring
results
as
required
under
paragraph
(
a)(
1)
of
this
section
or
modeling
as
required
under
paragraph
(
a)(
2)
of
this
section.
You
must
prepare
and
submit
your
system
specific
study
plan
to
the
State
according
to
the
schedule
in
§
141.600(
c).

(
1)
Existing
monitoring
results.
You
may
comply
by
submitting
monitoring
results
collected
before
you
are
required
to
begin
monitoring
under
§
141.600(
c).
The
monitoring
results
and
analysis
must
meet
the
criteria
in
paragraphs
(
a)(
1)(
i)
and
(
a)(
1)(
ii)
of
this
section.

(
i)
Minimum
requirements.
(
A)
TTHM
and
HAA5
results
must
be
based
on
samples
collected
and
analyzed
in
accordance
with
§
141.131.
Samples
must
be
collected
no
earlier
than
five
years
prior
to
the
study
plan
submission
date.

(
B)
The
monitoring
locations
and
frequency
must
meet
the
conditions
identified
in
this
paragraph
(
a)(
1)(
i)(
B).
Each
location
must
be
sampled
once
during
the
month
of
highest
TTHM
or
highestpeak
historical
month
for
TTHM
levels
or
HAA5
levels
or
the
month
of
warmest
water
temperature
for
every
12
months
of
data
submitted
for
that
location.
Monitoring
results
must
include
all
subpart
L
compliance
monitoring
results
plus
additional
monitoring
results
as
necessary
to
meet
minimum
sample
requirements.
315
System
Type
Population
Size
Category
Number
of
Monitoring
Locations
Number
of
Samples
Subpart
H
TTHM
HAA5
Surface
Water
<
500
3
3
3
500­
3,300
3
9
9
3,301­
9,999
6
36
36
10,000­
49,999
12
72
72
50,000­
249,999
24
144
144
250,000­
999,999
36
216
216
1,000,000­
4,999,999
48
288
288
$
5,000,000
60
360
360
Ground
Water
<
500
3
3
3
500­
9,999
3
9
9
10,000­
99,999
12
48
48
100,000­
499,999
18
72
72
$
500,000
24
96
96
(
ii)
Reporting
monitoring
results.
You
must
report
the
information
in
this
paragraph
(
a)(
1)(
ii).

(
A)
You
must
report
previously
collected
monitoring
results
and
certify
that
the
reported
monitoring
results
include
all
compliance
and
non­
compliance
results
generated
during
the
time
period
beginning
with
the
first
reported
result
and
ending
with
the
most
recent
subpart
L
results.

(
B)
You
must
certify
that
the
samples
were
representative
of
the
entire
distribution
system
and
that
treatment,
and
distribution
system
have
not
changed
significantly
since
the
samples
were
collected.

(
C)
Your
system
specific
study
monitoring
plan
must
include
a
schematic
of
your
distribution
system
(
including
distribution
system
entry
points
and
their
sources,
and
storage
facilities),
with
notes
indicating
316
the
locations
and
dates
of
all
completed
or
planned
system
specific
study
monitoring.

(
D)
Your
system
specific
study
plan
must
specify
the
population
served
and
system
type
(
subpart
H
or
ground
water).

(
E)
You
must
retain
a
complete
copy
of
your
system
specific
study
plan
submitted
under
this
paragraph
(
a)(
1),
including
any
State
modification
of
your
system
specific
study
plan,
for
as
long
as
you
are
required
to
retain
your
IDSE
report
under
paragraph
(
b)(
5)
of
this
section.

(
F)
If
a
you
submit
previously
collected
data
that
fully
meet
the
number
of
samples
required
under
paragraph
(
a)(
1)(
i)(
B)
of
this
section
and
the
State
rejects
some
of
the
data,
you
must
either
conduct
additional
monitoring
to
replace
rejected
data
on
a
schedule
the
State
approves
or
conduct
standard
monitoring
under
§
141.601.

(
2)
Modeling.
You
may
comply
through
analysis
of
an
extended
period
simulation
hydraulic
model.
The
extended
period
simulation
hydraulic
model
and
analysis
must
meet
the
criteria
in
this
paragraph
(
a)(
2).

(
i)
Minimum
requirements.
(
A)
The
model
must
simulate
24
hour
variation
in
demand
and
show
a
consistently
repeating
24
hour
pattern
of
residence
time.

(
B)
The
model
must
represent
the
criteria
listed
in
paragraphs
(
a)(
2)(
i)(
B)(
1)
through
(
9)
of
this
section.

(
1)
75%
of
pipe
volume;

(
2)
50%
of
pipe
length;

(
3)
aAll
pressure
zones;

(
4)
aAll
12­
inch
diameter
and
larger
pipes;

(
5)
aAll
8­
inch
and
larger
pipes
that
connect
pressure
zones,
influence
zones
from
different
sources,

storage
facilities,
major
demand
areas,
pumps,
and
control
valves,
or
are
known
or
expected
to
be
significant
conveyors
of
water;

(
6)
aAll
6­
inch
and
larger
pipes
that
connect
remote
areas
of
a
distribution
system
to
the
main
portion
of
the
system;

(
7)
aAll
storage
facilities
with
standard
operations
represented
in
the
model;
and
317
(
8)
aAll
active
pump
stations
with
controls
represented
in
the
model;
and
(
9)
aAll
active
control
valves.

(
C)
The
model
must
be
calibrated,
or
have
calibration
plans,
for
the
current
configuration
of
the
distribution
system
during
the
period
of
high
TTHM
formation
potential.
All
storage
facilities
must
be
evaluated
as
part
of
the
calibration
process.
All
required
calibration
must
be
completed
no
later
than
12
months
after
plan
submission.

(
ii)
Reporting
modeling.
Your
system
specific
study
plan
must
include
the
information
in
this
paragraph
(
a)(
2)(
ii).

(
A)
Tabular
or
spreadsheet
data
demonstrating
that
the
model
meets
requirements
in
paragraph
(
a)(
2)(
i)(
B)
of
this
section.

(
B)
A
description
of
all
calibration
activities
undertaken,
includingand
if
calibration
is
complete,
a
graph
of
predicted
tank
levels
versus
measured
tank
levels
for
the
storage
facility
with
the
highest
residence
time
in
each
pressure
zone
(
if
calibration
is
complete),
and
a
time
series
graph
of
the
residence
time
at
the
longest
residence
time
storage
facility
in
the
distribution
system
showing
the
predictions
for
the
entire
EPS
simulation
period
(
i.
e.,
from
time
zero
until
the
time
it
takes
to
for
the
model
to
reach
a
consistently
repeating
pattern
of
residence
time).

(
C)
Model
output
showing
preliminary
24
hour
average
residence
time
predictions
throughout
the
distribution
system.

(
D)
Timing
and
number
of
samples
representative
of
the
distribution
system
planned
for
at
least
one
roundmonitoring
period
of
TTHM
and
HAA5
dual
sample
monitoring
at
a
number
of
locations
no
less
than
would
be
required
for
the
system
under
standard
monitoring
in
§
141.601
during
the
historical
month
of
high
TTHM.
These
samples
must
be
taken
at
locations
other
than
existing
subpart
L
compliance
monitoring
locations.

(
E)
Description
of
how
all
requirements
will
be
completed
no
later
than
12
months
after
you
submit
your
system
specific
study
plan.
318
(
F)
Schematic
of
theyour
distribution
system
(
including
distribution
system
entry
points
and
their
sources,

and
storage
facilities),
with
notes
indicating
the
locations
and
dates
of
all
completed
system
specific
study
monitoring
(
if
calibration
is
complete)
and
all
subpart
L
compliance
monitoring.

(
G)
Population
served
and
system
type
(
subpart
H
or
ground
water).

(
H)
You
must
retain
a
complete
copy
of
your
system
specific
study
plan
submitted
under
this
paragraph
(
a)(
2),
including
any
State
modification
of
your
system
specific
study
plan,
for
as
long
as
you
are
required
to
retain
your
IDSE
report
under
paragraph
(
b)(
57)
of
this
section.

(
iii)
If
you
submit
a
model
that
does
not
fully
meet
the
requirements
under
paragraph
(
a)(
2)
of
this
section,

you
must
addresscorrect
the
deficiencies
and
respond
to
State
inquiries
concerning
the
model.
If
you
fail
to
addresscorrect
deficiencies
or
respond
to
inquiries
to
the
State's
satisfaction,
you
must
conduct
standard
monitoring
under
§
141.601.

(
b)
IDSE
report.
Your
IDSE
report
must
include
the
elements
required
in
paragraphs
(
b)(
1)
through
(
b)(
56)
of
this
section.
You
must
submit
your
IDSE
report
according
to
the
schedule
in
§
141.600(
c).

(
1)
Your
IDSE
report
must
include
all
TTHM
and
HAA5
analytical
results
from
subpart
L
compliance
monitoring
and
all
system
specific
study
monitoring
conducted
during
the
period
of
the
system
specific
study
presented
in
a
tabular
or
spreadsheet
format
acceptable
to
the
State.
If
changed
from
your
system
specific
study
plan
submitted
under
paragraph
(
a)
of
this
section,
your
IDSE
report
must
also
include
a
schematic
of
your
distribution
system,
the
population
served;
and
system
type
(
subpart
H
or
ground
water).

(
2)
If
you
used
the
modeling
provision
under
paragraph
(
a)(
2)
of
this
section,
you
must
include
final
calibration
information
for
the
elements
described
in
paragraph
(
a)(
2)(
ii)(
B)
of
this
section,
and
a
24­
hour
time
series
graph
of
residence
time
for
each
subpart
V
compliance
monitoring
location
selected.

(
3)
You
must
recommend
and
justify
subpart
V
compliance
monitoring
locations
and
timing
based
on
the
protocol
in
§
141.605.

(
4)
Your
IDSE
report
must
include
an
explanation
of
any
deviations
from
your
approved
system
specific
319
study
plan.

(
45)
Your
IDSE
report
must
include
the
basis
(
analytical
results
and
modeling
results)
and
justification
you
used
to
select
the
recommended
subpart
V
monitoring
locations.

(
56)
You
may
submit
your
IDSE
report
in
lieu
of
your
system
specific
study
plan
on
the
schedule
identified
in
§
141.600(
c)
for
submission
of
the
system
specific
study
plan
if
you
believe
that
you
have
the
necessary
information
by
the
time
that
the
system
specific
study
plan
is
due.
If
you
elect
this
approach,

your
IDSE
report
must
also
include
all
information
required
under
paragraph
(
a)
of
this
section.

(
67)
You
must
retain
a
complete
copy
of
your
IDSE
report
submitted
under
this
section
for
10
years
after
the
date
that
you
submitted
your
IDSE
report.
If
the
State
modifies
the
subpart
V
monitoring
requirements
that
you
recommended
in
your
IDSE
report
or
if
the
State
approves
alternative
monitoring
locations,
you
must
keep
a
copy
of
the
State's
notification
on
file
for
10
years
after
the
date
of
the
State's
notification.

You
must
make
the
IDSE
report
and
any
State
notification
available
for
review
by
the
State
or
the
public.

§
141.603
40/
30
certification.

(
a)
Eligibility.
You
are
eligible
for
40/
30
certification
if
you
have
taken
all
requiredhad
no
TTHM
or
HAA5
monitoring
violations
under
subpart
L
compliance
samplesof
this
part
and
no
individual
sample
exceeded
0.040
mg/
L
for
TTHM
or
0.030
mg/
L
for
HAA5
during
the
periodan
eight
consecutive
calendar
quarter
period
beginning
no
earlier
than
the
date
specified
in
this
paragraph
(
a).
320
If
your
40/
30
Certification
Is
Due
Then
your
eligibility
for
40/
30
certification
is
based
on
eight
consecutive
calendar
quarters
of
subpart
L
compliance
monitoring
results
during
this
periodbeginning
no
earlier
than
1
(
1)
[
date
six
mos
following
publication
of
final
rule]
April
2004­
March
2006(
2)
[
date
12
mos
following
publication
of
final
rule]
October
2004­
September1,
2006
January
2004
(
32)
[
date
18
mos
following
publication
of
final
rule]
April
2005­
March1,
2007
January
2004
(
43)
[
date
24
mos
following
publication
of
final
rule]
October
2005­
September1,
2007
January
2005
(
4)
April
1,
2008
January
2005
1
Unless
you
are
on
reduced
monitoring
under
subpart
L
of
this
part
and
were
not
required
to
monitor
during
the
specified
period.
If
you
did
not
monitor
during
the
specified
period,
you
must
base
your
eligibility
on
compliance
samples
taken
during
the
12
months
preceding
the
specified
period.

(
b)
40/
30
certification.
(
1)
You
must
certify
to
your
State
that
every
individual
compliance
sample
taken
under
subpart
L
of
this
part
during
the
periods
specified
in
paragraph
(
a)
of
this
section
were
#
0.040
mg/
L
for
TTHM
and
#
0.030
mg/
L
for
HAA5.
In
addition,,
and
that
you
musthave
not
have
had
any
TTHM
or
HAA5
monitoring
violations
during
the
period
specified
in
paragraph
(
a)
of
this
section.

(
2)
The
State
may
require
you
to
submit
compliance
monitoring
results,
distribution
system
schematics,

orand/
or
recommended
subpart
V
compliance
monitoring
locations
in
addition
to
your
certification.
If
you
fail
to
submit
the
requested
information,
the
State
may
require
standard
monitoring
under
§
141.601
or
a
system
specific
study
under
§
141.602.

(
3)
The
State
may
still
require
standard
monitoring
under
§
141.601
or
a
system
specific
study
under
§
141.602
even
if
you
meet
the
criteria
in
paragraph
(
a)
of
this
section.

(
4)
You
must
retain
a
complete
copy
of
your
certification
submitted
under
this
section
for
10
years
after
the
date
that
you
submitted
your
certification.
You
must
make
the
certification,
all
data
upon
which
the
certification
is
based,
and
any
State
notification
available
for
review
by
the
State
or
the
public.

§
141.604
Very
small
system
waivers.
321
(
a)
If
you
serve
fewer
than
500
people
and
you
have
taken
TTHM
and
HAA5
samples
under
subpart
L
of
this
part,
you
are
not
required
to
comply
with
this
subpart
unless
the
State
notifies
you
that
you
must
conduct
standard
monitoring
under
§
141.601
or
a
system
specific
study
under
§
141.602.

(
b)
If
you
have
not
taken
TTHM
and
HAA5
samples
under
subpart
L
of
this
part
or
if
the
State
notifies
you
that
you
must
comply
with
this
subpart,
you
must
conduct
standard
monitoring
under
§
141.601
or
a
system
specific
study
under
§
141.602.

§
141.605
Subpart
V
compliance
monitoring
location
recommendations.

(
a)
Your
IDSE
report
must
include
your
recommendations
and
justification
for
where
and
during
what
month(
s)
TTHM
and
HAA5
monitoring
for
subpart
V
of
this
part
should
be
conducted.
You
must
base
your
recommendations
on
the
criteria
in
paragraphs
(
b)
through
(
e)
of
this
section.

(
b)
You
must
select
the
number
of
monitoring
locations
specified
in
the
table
in
this
paragraph
(
b).
You
will
use
these
recommended
locations
as
subpart
V
routine
compliance
monitoring
locations,
unless
State
requires
different
or
additional
locations.
You
should
distribute
locations
throughout
the
distribution
system
to
the
extent
possible.
322
Source
Water
Type
Population
Size
Category
Monitoring
Frequency
1
Distribution
System
Monitoring
Location
Total
per
monitoring
period
2
Highest
TTHM
Locations
Highest
HAA5
Locations
Existing
Subpart
L
Compliance
Locations
Subpart
H
<
500
per
year
2
2
1
1
!

500­
3,300
per
quarter
2
2
1
1
!

3,301­
9,999
per
quarter
2
1
1
!

10,000­
49,999
per
quarter
4
2
1
1
50,000­
249,999
per
quarter
8
3
3
2
250,000­
999,999
per
quarter
12
5
4
3
1,000,000­
4,999,999
per
quarter
16
6
6
4
$
5,000,000
per
quarter
20
8
7
5
Ground
Water
<
500
per
year
2
2
1
1
!

500­
9,999
per
year
2
1
1
!

10,000­
99,999
per
quarter
4
2
1
1
100,000­
499,999
per
quarter
6
3
2
1
$
500,000
per
quarter
8
3
3
2
1
All
systems
must
take
at
least
one
dual
sample
setmonitor
during
month
of
highest
DBP
concentrations.
2
Systems
on
quarterly
monitoring
must
take
dual
sample
sets
every
90
days
at
each
monitoring
location,
except
for
subpart
H
systems
serving
500­
3,300.
2
System
iss
on
annual
monitoring
and
subpart
H
systems
serving
500­
3,300
are
required
to
take
individual
TTHM
and
HAA5
samples
(
instead
of
a
dual
sample
set)
at
the
locations
with
the
highest
TTHM
and
HAA5
concentrations,
respectively.
Only
one
location
with
a
dual
sample
set
per
monitoring
period
is
needed
if
highest
TTHM
and
HAA5
concentrations
occur
at
the
same
location,
and
month,
if
monitored
annually).

(
c)
You
must
recommend
subpart
V
compliance
monitoring
locations
based
on
standard
monitoring
results,
system
specific
study
results,
and
subpart
L
compliance
monitoring
results.
You
must
follow
the
protocol
in
paragraphs
(
c)(
1)
through
(
4c)(
8)
of
this
section.
If
required
to
monitor
at
more
than
foureight
locations,
you
must
repeat
the
protocol
as
necessary,
alternating
between
locations
with
the
highest
HAA5
LRAA
and
the
highest
TTHM
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location
for
choosing
locations
under
paragraphs
(
c)(
3)
and
(
c)(
4).
If
you
do
not
have
existing
subpart
L
compliance
323
monitoring
results
or
if
you
do
not
have
enough
existing
subpart
L
compliance
monitoring
results,
you
must
repeat
the
protocol
as
necessary
using,
skipping
the
provisions
of
paragraphs
(
c)(
13),
(
c)(
2),
and
(
c)(
47)
of
this
section
as
necessary,
until
you
have
identified
the
required
total
number
of
monitoring
locations.

(
1)
Location
with
the
highest
TTHM
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location.

(
2)
Location
with
the
highest
HAA5
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location.

(
3)
Existing
subpart
L
average
residence
time
compliance
monitoring
location
(
maximum
residence
time
compliance
monitoring
location
for
ground
water
systems)
with
the
highest
HAA5
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location.

(
4)
Location
with
the
highest
TTHM
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location.

(
5)
Location
with
the
highest
TTHM
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location.

(
6)
Location
with
the
highest
HAA5
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location.

(
7)
Existing
subpart
L
average
residence
time
compliance
monitoring
location
(
maximum
residence
time
compliance
monitoring
location
for
ground
water
systems)
with
the
highest
TTHM
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location.

(
8)
Location
with
the
highest
HAA5
LRAA
not
previously
selected
as
a
subpart
V
monitoring
location.

(
d)
You
may
recommend
locations
other
than
those
specified
in
paragraph
(
c)
of
this
section
if
you
include
a
rationale
for
selecting
other
locations.
If
the
State
approves
the
alternate
locations,
you
must
monitor
at
these
locations
to
determine
compliance
under
subpart
V
of
this
part.

(
e)
Your
recommended
schedule
must
include
subpart
V
monitoring
during
the
peak
historical
month
for
TTHM
and
HAA5
concentration,
unless
the
State
approves
another
month.
Once
you
have
identified
the
peak
historical
month,
and
if
you
are
required
to
conduct
routine
monitoring
at
least
quarterly,
you
must
schedule
subpart
V
compliance
monitoring
at
a
regular
frequency
of
every
90
days
or
fewer.

20.
Part
141
is
amended
by
adding
new
subpart
V
to
read
as
follows:
324
Subpart
V­
Stage
2
Disinfection
Byproducts
Requirements
Sec.

141.620
General
requirements.

141.621
Routine
monitoring.

141.622
Subpart
V
monitoring
plan.

141.623
Reduced
monitoring.

141.624
Additional
requirements
for
consecutive
systems.

141.625
Conditions
requiring
increased
monitoring.

141.626
Operational
evaluation
levels.

141.627
Requirements
for
remaining
on
reduced
TTHM
and
HAA5
monitoring
based
on
subpart
L
results.

141.628
Requirements
for
remaining
on
increased
TTHM
and
HAA5
monitoring
based
on
subpart
L
results.

141.629
Reporting
and
recordkeeping
requirements.

Subpart
V­
Stage
2
Disinfection
Byproducts
Requirements
§
141.620
General
requirements.

(
a)
The
requirements
of
subpart
V
of
this
part
constitute
national
primary
drinking
water
regulations.

The
regulations
in
this
subpart
establish
monitoring
and
other
requirements
for
achieving
compliance
with
maximum
contaminant
levels
based
on
locational
running
annual
averages
(
LRAA)
for
total
trihalomethanes
(
TTHM)
and
haloacetic
acids
(
five)(
HAA5),
and
for
achieving
compliance
with
maximum
residual
disinfectant
residuals
for
chlorine
and
chloramine
for
certain
consecutive
systems.

(
b)
Applicability.
You
are
subject
to
these
requirements
if
your
system
is
a
community
water
system
or
a
nontransient
noncommunity
water
system
that
uses
a
primary
or
residual
disinfectant
other
than
ultraviolet
light
or
delivers
water
that
has
been
treated
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
325
light.

(
c)
Schedule.
You
must
comply
with
the
requirements
in
this
subpart
on
the
schedule
in
the
following
table
based
on
your
system
type.

IF
YOU
ARE
THIS
TYPE
OF
SYSTEM
YOU
MUST
COMPLY
WITH
SUBPART
V
MONITORING
BY:
1
Systems
that
are
not
part
of
a
combined
distribution
system
and
systems
that
serve
the
largest
population
in
the
combined
distribution
system
(
1)
System
serving
$
100,000
[
date
72
mos
following
publication
of
final
rule]
April
1,
2012
(
2)
System
serving
50,000­
99,999
[
date
78
mos
following
publication
of
final
rule]
October
1,
2012
(
3)
System
serving
10,000­
49,999
[
date
90
mos
following
publication
of
final
rule]
October
1,
2013
(
4)
System
serving
<
10,000
[
date
90
mos
following
publication
of
final
rule]
October
1,
2013
if
no
Cryptosporidium
monitoring
is
required
under
§
141.701(
a)(
4)
OR
October
1,
2014
if
Cryptosporidium
monitoring
is
required
under
§
141.701(
a)(
4)
OR
[
date
102
mos
following
publication
of
final
rule]
if
Cryptosporidium
monitoring
is
required
under
§
141.701or
(
a)(
6)

Other
systems
that
are
part
of
a
combined
distribution
system
(
5)
Consecutive
system
or
wholesale
system
­
at
the
same
time
as
the
system
with
the
earliest
compliance
date
in
the
combined
distribution
system
1
The
State
may
grant
up
to
an
additional
24
months
for
compliance
with
MCLs
and
operational
evaluation
levels
if
you
require
capital
improvements
to
comply
with
an
MCL.

(
6)
Your
monitoring
frequency
is
specified
in
§
141.621(
a)(
2).

(
i)
If
you
are
required
to
conduct
quarterly
monitoring,
you
must
begin
monitoring
in
the
first
full
calendar
quarter
that
followsincludes
the
compliance
date
in
the
table
in
this
paragraph
(
c).

(
ii)
If
you
are
required
to
conduct
monitoring
at
a
frequency
that
is
less
than
quarterly,
you
must
begin
monitoring
in
the
calendar
month
recommended
in
the
IDSE
report
prepared
under
§
141.601
or
§
141.602
or
the
calendar
month
identified
in
the
subpart
V
monitoring
plan
developed
under
§
141.622
no
later
than
326
12
months
after
the
compliance
date
in
this
table.

(
7)
If
you
are
required
to
conduct
quarterly
monitoring,
you
must
make
compliance
calculations
at
the
end
of
the
fourth
calendar
quarter
that
follows
the
compliance
date
and
at
the
end
of
each
subsequent
quarter
(
or
earlier
if
the
LRAA
calculated
based
on
fewer
than
four
quarters
of
data
would
cause
the
MCL
to
be
exceeded
regardless
of
the
monitoring
results
of
subsequent
quarters).
If
you
are
required
to
conduct
monitoring
at
a
frequency
that
is
less
than
quarterly,
you
must
make
compliance
calculations
beginning
with
the
first
compliance
sample
taken
after
the
compliance
date.

(
8)
For
the
purpose
of
the
schedule
in
this
paragraph
(
c),
the
State
may
determine
that
the
combined
distribution
system
does
not
include
certain
consecutive
systems
based
on
factors
such
as
receiving
water
from
a
wholesale
system
only
on
an
emergency
basis
or
receiving
only
a
small
percentage
and
small
volume
of
water
from
a
wholesale
system.
The
State
may
also
determine
that
the
combined
distribution
system
does
not
include
certain
wholesale
systems
based
on
factors
such
as
delivering
water
to
a
consecutive
system
only
on
an
emergency
basis
or
delivering
only
a
small
percentage
and
small
volume
of
water
to
a
consecutive
system.

(
d)
Monitoring
and
compliance.

(
1)
Systems
required
to
monitor
quarterly.
To
comply
with
subpart
V
MCLs
in
§
141.64(
b)(
2),
you
must
calculate
LRAAs
for
TTHM
and
HAA5
using
monitoring
results
collected
under
this
subpart
and
determine
that
each
LRAA
does
not
exceed
the
MCL.
If
you
fail
to
complete
four
consecutive
quarters
of
monitoring,
you
must
calculate
compliance
with
the
MCL
based
on
the
average
of
the
available
data
from
the
most
recent
four
quarters.
If
you
take
more
than
one
sample
per
quarter
at
a
monitoring
location,
you
must
average
all
samples
taken
in
the
quarter
at
that
location
to
determine
a
quarterly
average
to
be
used
in
the
LRAA
calculation.

(
2)
Systems
required
to
monitor
yearly
or
less
frequently.
To
determine
compliance
with
subpart
V
MCLs
in
§
141.64(
b)(
2),
you
must
determine
that
each
sample
taken
is
less
than
the
MCL.
If
any
sample
327
exceeds
the
MCL,
you
must
comply
with
the
requirements
of
§
141.625.
If
no
sample
exceeds
the
MCL,

the
sample
result
for
each
monitoring
location
is
considered
the
LRAA
for
that
monitoring
location.

(
e)
Failure
to
monitor
will
be
treated
as
a
monitoring
violation
for
the
entire
period
covered
by
a
locational
running
annual
average
compliance
calculation
for
the
subpart
V
MCLs
in
§
141.64(
b)(
2).
You
are
in
violation
of
the
monitoring
requirements
for
each
quarter
that
a
monitoring
result
would
be
used
in
calculating
an
LRAA
if
you
fail
to
monitor.

§
141.621
Routine
monitoring.

(
a)
Monitoring.
(
1)
If
you
submitted
an
IDSE
report,
you
must
begin
monitoring
at
the
locations
and
months
you
have
recommended
in
your
IDSE
report
submitted
under
§
141.605
following
the
schedule
in
§
141.620(
c),
unless
the
State
requires
other
locations
or
additional
locations
after
its
review.
If
you
submitted
a
40/
30
certification
under
§
141.603
or
you
qualified
for
a
very
small
system
waiver
under
§
141.604
or
you
are
a
nontransient
noncommunity
water
system
serving
<
10,000,
you
must
monitor
at
the
location(
s)
and
dates
identified
in
your
monitoring
plan
in
§
141.132(
f),
updated
as
required
by
§
141.622.

(
2)
You
must
monitor
at
no
fewer
than
the
number
of
locations
identified
in
this
paragraph
(
a)(
2).
328
Source
Water
Type
Population
Size
Category
Monitoring
Frequency
1
Distribution
System
Monitoring
Location
Total
per
Monitoring
Period
2
Subpart
H
<
500
per
year
2
2
500­
3,300
per
quarter
2
2
3,301­
9,999
per
quarter
2
10,000­
49,999
per
quarter
4
50,000­
249,999
per
quarter
8
250,000­
999,999
per
quarter
12
1,000,000­
4,999,999
per
quarter
16
$
5,000,000
per
quarter
20
Ground
Water
<
500
per
year
2
2
500­
9,999
per
year
2
10,000­
99,999
per
quarter
4
100,000­
499,999
per
quarter
6
$
500,000
per
quarter
8
1
All
systems
must
take
at
least
one
dual
sample
setmonitor
during
month
of
highest
DBP
concentrations.
2
Systems
on
quarterly
monitoring
must
take
dual
sample
sets
every
90
days
at
each
monitoring
location,
except
for
subpart
H
systems
serving
500­
3,300.
2
System
iss
on
annual
monitoring
and
subpart
H
systems
serving
500­
3,300
are
required
to
take
individual
TTHM
and
HAA5
samples
(
instead
of
a
dual
sample
set)
at
the
locations
with
the
highest
TTHM
and
HAA5
concentrations,
respectively.
Only
one
location
with
a
dual
sample
set
per
monitoring
period
is
needed
if
highest
TTHM
and
HAA5
concentrations
occur
at
the
same
location
(
and
month,
if
monitored
annually).

(
3)
If
you
are
an
undisinfected
system
that
begins
using
a
disinfectant
other
than
UV
light
after
the
dates
in
subpart
U
of
this
part
for
complying
with
the
Initial
Distribution
System
Evaluation
requirements,
you
must
consult
with
the
State
to
identify
compliance
monitoring
locations
for
this
subpart.
You
must
then
develop
a
monitoring
plan
under
§
141.622
that
includes
those
monitoring
locations.

(
b)
Analytical
methods.
You
must
use
an
approved
method
listed
in
§
141.131
for
TTHM
and
HAA5
analyses
in
this
subpart.
Analyses
must
be
conducted
by
laboratories
that
have
received
certification
by
EPA
or
the
State
as
specified
in
§
141.131.
329
§
141.622
Subpart
V
monitoring
plan.

(
a)
Subpart
V
monitoring
plan.
(
1)
You
must
develop
and
implement
a
monitoring
plan
to
be
kept
on
file
for
State
and
public
review.
The
monitoring
plan
must
contain
the
elements
in
paragraphs
(
a)(
1)(
i)
through
(
a)(
1)(
iv)
of
this
section
and
be
complete
no
later
than
the
date
you
conduct
your
initial
monitoring
under
this
subpart.

(
i)
mMonitoring
locations;

(
ii)
mMonitoring
dates;

(
iii)
cCompliance
calculation
procedures;
and
(
iv)
mMonitoring
plans
for
any
other
systems
in
the
combined
distribution
system
if
the
State
has
reduced
monitoring
requirements
under
the
State
authority
in
§
142.16(
m).

(
2)
If
you
were
not
required
to
submit
an
IDSE
report
under
either
§
141.601
or
§
141.602,
and
you
do
not
have
sufficient
subpart
L
monitoring
locations
to
identify
the
required
number
of
subpart
V
compliance
monitoring
locations
indicated
in
§
141.605(
b),
you
must
identify
additional
locations
by
alternating
selection
of
locations
representing
high
TTHM
levels
and
high
HAA5
levels
until
the
required
number
of
compliance
monitoring
locations
have
been
identified.
You
must
also
provide
the
rationale
for
identifying
the
locations
as
having
high
levels
of
TTHM
or
HAA5.
If
you
have
more
subpart
L
monitoring
locations
than
required
for
subpart
V
compliance
monitoring
in
§
141.605(
b),
you
must
identify
which
locations
you
will
use
for
subpart
V
compliance
monitoring
by
alternating
selection
of
locations
representing
high
TTHM
levels
and
high
HAA5
levels
until
the
required
number
of
subpart
V
compliance
monitoring
locations
have
been
identified.

(
b)
If
you
are
a
subpart
H
system
serving
>
3,300
people,
you
must
submit
a
copy
of
your
monitoring
plan
to
the
State
prior
to
the
date
you
conduct
your
initial
monitoring
under
this
subpart,
unless
your
IDSE
report
submitted
under
subpart
U
of
this
part
contains
all
the
information
required
by
this
section.

(
c)
You
may
revise
your
monitoring
plan
to
reflect
changes
in
treatment,
distribution
system
operations
330
and
layout
(
including
new
service
areas),
or
other
factors
that
may
affect
TTHM
or
HAA5
formation,
or
for
State­
approved
reasons,
after
consultation
with
the
State
regarding
the
need
for
changes
and
the
appropriateness
of
changes.
If
you
change
monitoring
locations,
you
must
replace
existing
compliance
monitoring
locations
with
the
lowest
LRAA
with
new
locations
that
reflect
the
current
distribution
system
locations
with
expected
high
TTHM
or
HAA5
levels.
The
State
may
also
require
modifications
in
your
monitoring
plan.
If
you
are
a
subpart
H
system
serving
>
3,300
people,
you
must
submit
a
copy
of
your
modified
monitoring
plan
to
the
State
prior
to
the
date
you
are
required
to
comply
with
the
revised
monitoring
plan.

§
141.623
Reduced
monitoring.

(
a)
You
may
reduce
monitoring
to
the
level
specified
in
the
table
in
this
paragraph
(
a)
any
time
the
LRAA
is
#
0.040
mg/
L
for
TTHM
and
#
0.030
mg/
L
for
HAA5
at
all
monitoring
locations.
You
may
only
use
data
collected
under
the
provisions
of
this
subpart
or
subpart
L
of
this
part
to
qualify
for
reduced
monitoring.
In
addition,
the
source
water
annual
average
TOC
level,
before
any
treatment,
must
be
#
4.0
mg/
L
at
each
treatment
plant
treating
surface
water
or
ground
water
under
the
direct
influence
of
surface
water,
based
on
monitoring
conducted
under
either
§
141.132(
b)(
1)(
iii)
or
§
141.132(
d).
331
Source
Water
Type
Population
Size
Category
Monitoring
Frequency
1
Distribution
System
Monitoring
Location
per
Monitoring
Period
Subpart
H
<
500
­
monitoring
may
not
be
reduced
500­
3,300
per
year
1
TTHM
and
1
HAA5
sample:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement;
1
dual
sample
set
per
year
if
the
highest
TTHM
and
HAA5
measurements
occurred
at
the
same
location
and
quarter.

3,301­
9,999
per
year
2
dual
sample
sets:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement
10,000­
49,999
per
quarter
2
dual
sample
sets
at
the
locations
with
the
highest
TTHM
and
highest
HAA5
LRAAs
50,000­
249,999
per
quarter
4
dual
sample
sets
­
at
the
locations
with
the
two
highest
TTHM
and
two
highest
HAA5
LRAAs
250,000­
999,999
per
quarter
6
dual
sample
sets
­
at
the
locations
with
the
three
highest
TTHM
and
three
highest
HAA5
LRAAs
1,000,000­
4,999,999
per
quarter
8
dual
sample
sets
­
at
the
locations
with
the
four
highest
TTHM
and
four
highest
HAA5
LRAAs
$
5,000,000
per
quarter
10
dual
sample
sets
­
at
the
locations
with
the
five
highest
TTHM
and
five
highest
HAA5
LRAAs
Ground
Water
<
500
every
third
year
1
TTHM
and
1
HAA5
sample:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement;
1
dual
sample
set
per
year
if
the
highest
TTHM
and
HAA5
measurements
occurred
at
the
same
location
and
quarter.

500­
9,999
per
year
1
TTHM
and
1
HAA5
sample:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement;
1
dual
sample
set
per
year
if
the
highest
TTHM
and
HAA5
measurements
occurred
at
the
same
location
and
quarter.

10,000­
99,999
per
year
2
dual
sample
sets:
one
at
the
location
and
during
the
quarter
with
the
highest
TTHM
single
measurement,
one
at
the
location
and
during
the
quarter
with
the
highest
HAA5
single
measurement
100,000­
499,999
per
quarter
2
dual
sample
sets;
at
the
locations
with
the
highest
TTHM
and
highest
HAA5
LRAAs
$
500,000
per
quarter
4
dual
sample
sets
at
the
locations
with
the
two
highest
TTHM
332
1
Systems
on
quarterly
monitoring
must
take
dual
sample
sets
every
90
days.

(
b)
You
may
remain
on
reduced
monitoring
as
long
as
the
TTHM
LRAA
#
0.040
mg/
L
and
the
HAA5
LRAA
#
0.030
mg/
L
at
each
monitoring
location
(
for
systems
with
quarterly
reduced
monitoring)
or
each
TTHM
sample
#
0.060
mg/
L
and
each
HAA5
sample
#
0.045
mg/
L
(
for
systems
with
annual
or
less
frequent
monitoring).
In
addition,
the
source
water
annual
average
TOC
level,
before
any
treatment,
must
be
#
4.0
mg/
L
at
each
treatment
plant
treating
surface
water
or
ground
water
under
the
direct
influence
of
surface
water,
based
on
monitoring
conducted
under
either
§
141.132(
b)(
1)(
iii)
or
§
141.132(
d).

(
c)
If
the
LRAA
based
on
quarterly
monitoring
at
any
monitoring
location
exceeds
either
0.040
mg/
L
for
TTHM
or
0.030
mg/
L
for
HAA5
or
if
the
annual
(
or
less
frequent)
sample
at
any
location
exceeds
either
0.060
mg/
L
for
TTHM
or
0.045
mg/
L
for
HAA5,
or
if
the
source
water
annual
average
TOC
level,
before
any
treatment,
>
4.0
mg/
L
at
any
treatment
plant
treating
surface
water
or
ground
water
under
the
direct
influence
of
surface
water,
you
must
resume
routine
monitoring
under
§
141.621
or
begin
increased
monitoring
if
§
141.625
applies.

(
c)
The
State
may
return
your
system
to
routine
monitoring
at
the
State's
discretion.

§
141.624
Additional
requirements
for
consecutive
systems.

If
you
are
a
consecutive
system
that
does
not
add
a
disinfectant
but
delivers
water
that
has
been
disinfected
with
treatmenttreated
with
a
primary
or
residual
disinfectant
other
than
ultraviolet
light,
you
must
comply
with
analytical
and
monitoring
requirements
for
chlorine
and
chloramines
in
§
§
141
§
141.131
(
c)
and
141
§
141.132(
c)(
1)
and
the
compliance
requirements
in
§
141.133(
c)(
1)
beginning
[
DATE
THREE
YEARS
AFTER
PUBLICATION
OF
FINAL
RULE]
April
1,
2009,
unless
required
earlier
by
the
State,
and
report
monitoring
results
under
§
141.134(
c).

§
141.625
Conditions
requiring
increased
monitoring.
333
(
a)
If
you
are
required
to
monitor
at
a
particular
location
annually
or
less
frequently
than
annually
under
§
§
141
§
141.621
or
141
§
141.623,
you
must
increase
monitoring
to
dual
sample
sets
once
per
quarter
(
taken
every
90
days)
at
all
locations
if
a
TTHM
sample
is
>
0.080
mg/
L
or
a
HAA5
sample
is
>
0.060
mg/
L
at
any
location.

(
b)
You
are
in
violation
of
the
MCL
when
the
LRAA
exceeds
the
subpart
V
MCLs
in
§
141.64(
b)(
2),

calculated
based
on
four
consecutive
quarters
of
monitoring
(
or
the
LRAA
calculated
based
on
fewer
than
four
quarters
of
data
if
the
MCL
would
be
exceeded
regardless
of
the
monitoring
results
of
subsequent
quarters).
You
are
in
violation
of
the
monitoring
requirements
for
each
quarter
that
a
monitoring
result
would
be
used
in
calculating
an
LRAA
if
you
fail
to
monitor.

(
c)
You
may
return
to
routine
monitoring
once
you
have
conducted
increased
monitoring
for
at
least
four
consecutive
quarters
and
the
LRAA
for
every
monitoring
location
is
#
0.060
mg/
L
for
TTHM
and
#
0.045
mg/
L
for
HAA5.

§
141.626
Operational
evaluation
levels.

(
a)
You
have
exceeded
the
operational
evaluation
level
at
any
monitoring
location
where
the
sum
of
the
two
previous
quarters'
TTHM
results
plus
twice
the
current
quarter's
TTHM
result
,
divided
by
4
to
determine
an
average,
exceeds
0.080
mg/
L,
or
where
the
sum
of
the
two
previous
quarters'
HAA5
results
plus
twice
the
current
quarter's
HAA5
result,
divided
by
4
to
determine
an
average,
exceeds
0.060
mg/
L.

(
b)
Operational
evaluation.

(
1)
If
you
exceed
the
operational
evaluation
level,
you
must
conduct
an
operational
evaluation
and
submit
a
written
report
of
the
evaluation
to
the
State
no
later
than
90
days
after
being
notified
of
the
analytical
result
that
causes
you
to
exceed
the
operational
evaluation
level.
The
written
report
must
be
made
available
to
the
public
upon
request.

(
2)
Your
operational
evaluation
must
include
an
examination
of
system
treatment
and
distribution
334
operational
practices,
including
storage
tank
operations,
excess
storage
capacity,
distribution
system
flushing,
changes
in
sources
or
source
water
quality,
and
treatment
changes
or
problems
that
may
contribute
to
TTHM
and
HAA5
formation
and
what
steps
could
be
considered
to
minimize
future
exceedences.

(
i)
You
may
request
and
the
State
may
allow
you
to
limit
the
scope
of
your
evaluation
if
you
are
able
to
identify
the
cause
of
the
operational
evaluation
level
exceedance.

(
ii)
Your
request
to
limit
the
scope
of
the
evaluation
does
not
extend
the
schedule
in
paragraph
(
b)(
1)
of
this
section
for
submitting
the
written
report.
The
State
must
approve
this
limited
scope
of
evaluation
in
writing
and
you
must
keep
that
approval
with
the
completed
report.

§
141.627
Requirements
for
remaining
on
reduced
TTHM
and
HAA5
monitoring
based
on
subpart
L
results.

You
may
remain
on
reduced
monitoring
after
the
dates
identified
in
§
141.620(
c)
for
compliance
with
this
subpart
only
if
you
qualify
for
a
40/
30
certification
under
§
141.603
or
have
received
a
very
small
system
waiver
under
§
141.604,
plus
you
meet
the
reduced
monitoring
criteria
in
§
141.623(
a),
and
you
do
not
change
or
add
monitoring
locations
from
those
used
for
compliance
monitoring
under
subpart
L
of
this
part.
If
your
monitoring
locations
under
this
subpart
differ
from
your
monitoring
locations
under
subpart
L
of
this
part,
you
may
not
remain
on
reduced
monitoring
after
the
dates
identified
in
§
141.620(
c)
for
compliance
with
this
subpart.

§
141.628
Requirements
for
remaining
on
increased
TTHM
and
HAA5
monitoring
based
on
subpart
L
results.

If
you
were
on
increased
monitoring
under
§
141.132(
b)(
1),
you
must
remain
on
increased
monitoring
until
you
qualify
for
a
return
to
routine
monitoring
under
§
141.625(
c).
You
must
conduct
increased
monitoring
335
under
§
141.625
at
the
monitoring
locations
in
the
monitoring
plan
developed
under
§
141.622
beginning
at
the
date
identified
in
§
141.620(
c)
for
compliance
with
this
subpart
and
remain
on
increased
monitoring
until
you
qualify
for
a
return
to
routine
monitoring
under
§
141.625(
c).

§
141.629
Reporting
and
recordkeeping
requirements.

(
a)
Reporting.
(
1)
You
must
report
the
following
information
for
each
monitoring
location
to
the
State
within
10
days
of
the
end
of
any
quarter
in
which
monitoring
is
required:

(
i)
Number
of
samples
taken
during
the
last
quarter.

(
ii)
Date
and
results
of
each
sample
taken
during
the
last
quarter.

(
iii)
Arithmetic
average
of
quarterly
results
for
the
last
four
quarters
for
each
monitoring
location
(
LRAA),
beginning
at
the
end
of
the
fourth
calendar
quarter
that
follows
the
compliance
date
and
at
the
end
of
each
subsequent
quarter.
If
the
LRAA
calculated
based
on
fewer
than
four
quarters
of
data
would
cause
the
MCL
to
be
exceeded
regardless
of
the
monitoring
results
of
subsequent
quarters,
you
must
report
this
information
to
the
State
as
part
of
the
first
report
due
following
the
compliance
date
or
anytime
thereafter
that
this
determination
is
made.
If
you
are
required
to
conduct
monitoring
at
a
frequency
that
is
less
than
quarterly,
you
must
make
compliance
calculations
beginning
with
the
first
compliance
sample
taken
after
the
compliance
date,
unless
you
are
required
to
conduct
increased
monitoring
under
§
141.625.

(
iv)
Whether,
based
on
§
141.64(
b)(
2)
and
this
subpart,
the
MCL
was
violated
at
any
monitoring
location.

(
v)
Any
operational
evaluation
levels
that
were
exceeded
during
the
quarter
and,
if
so,
the
location
and
date,
and
the
calculated
TTHM
and
HAA5
levels.

(
2)
If
you
are
a
subpart
H
system
seeking
to
qualify
for
or
remain
on
reduced
TTHM/
HAA5
monitoring,

you
must
report
the
following
source
water
TOC
information
for
each
treatment
plant
that
treats
surface
water
or
ground
water
under
the
direct
influence
of
surface
water
to
the
State
within
10
days
of
the
end
of
any
quarter
in
which
monitoring
is
required:
336
(
i)
The
number
of
source
water
TOC
samples
taken
each
month
during
last
quarter.

(
ii)
The
date
and
result
of
each
sample
taken
during
last
quarter.

(
iii)
The
quarterly
average
of
monthly
samples
taken
during
last
quarter
or
the
result
of
the
quarterly
sample.

(
iv)
The
running
annual
average
(
RAA)
of
quarterly
averages
from
the
past
four
quarters.

(
v)
Whether
the
RAA
exceeded
4.0
mg/
L.

(
3)
The
State
may
choose
to
perform
calculations
and
determine
whether
the
MCL
was
exceeded
or
the
system
is
eligible
for
reduced
monitoring
in
lieu
of
having
the
system
report
that
information
(
b)
Recordkeeping.
You
must
retain
any
subpart
V
monitoring
plans
and
your
subpart
V
monitoring
results
as
required
by
§
141.33.

PART
142
­
National
Primary
Drinking
Water
Regulations
Implementation
21.
The
authority
citation
for
part
142
continues
to
read
as
follows:

Authority:
42
U.
S.
C.
300f,
300g­
1,
300g­
2,
300g­
3,
300g­
4,
300g­
5,
300g­
6,
300j­
4,
300j­
9,
and
300j­
11.

22.
Section
142.14
is
amended
by
adding
paragraph
(
a)(
8)
to
read
as
follows:

§
142.14
Records
kept
by
States.

(
a)
***

(
8)
Any
decisions
made
pursuant
to
the
provisions
of
40
CFR
part
141,
subparts
U
and
V
of
this
part.

(
i)
IDSE
monitoring
plans,
plus
any
modifications
required
by
the
State,
must
be
kept
until
replaced
by
approved
IDSE
reports.

(
ii)
IDSE
reports
and
40/
30
certifications,
plus
any
modifications
required
by
the
State,
must
be
kept
337
until
replaced
or
revised
in
their
entirety.

(
iii)
Operational
evaluations
submitted
by
a
system
must
be
kept
for
10
years
following
submission.

*
*
*
*
*

23.
Section
142.16
is
amended
by
adding
paragraph
(
m)
to
read
as
follows:

§
142.16
Special
primacy
conditions.

*
*
*
*
*

(
m)
Requirements
for
States
to
adopt
40
CFR
part
141,
subparts
U
and
V.
In
addition
to
the
general
primacy
requirements
elsewhere
in
this
part,
including
the
requirements
that
State
regulations
be
at
least
as
stringent
as
federal
requirements,
an
application
for
approval
of
a
State
program
revision
that
adopts
40
CFR
part
141,
subparts
U
and
V,
must
contain
a
description
of
how
the
State
will
implement
a
procedure
for
addressing
modification
of
wholesale
system
and
consecutive
system
monitoring
on
a
case­
by­
case
basis
for
part
141
subpart
V
outside
the
provisions
of
§
141.29
of
this
chapter,
if
the
State
elects
to
use
such
an
authority.
The
procedure
must
ensure
that
all
systems
have
at
least
one
compliance
monitoring
location.

*
*
*
*
*
