e-CFR Data is current as of January 18, 2008 

Title 40: Protection of Environment

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Subpart W—Enhanced Treatment for Cryptosporidium

Source:   71 FR 769, Jan. 5, 2006, unless otherwise noted. 

General Requirements

§ 141.700   General requirements.

(a) The requirements of this subpart W are national primary drinking
water regulations. The regulations in this subpart establish or extend
treatment technique requirements in lieu of maximum contaminant levels
for Cryptosporidium. These requirements are in addition to requirements
for filtration and disinfection in subparts H, P, and T of this part.

(b) Applicability. The requirements of this subpart apply to all subpart
H systems, which are public water systems supplied by a surface water
source and public water systems supplied by a ground water source under
the direct influence of surface water.

(1) Wholesale systems, as defined in §141.2, must comply with the
requirements of this subpart based on the population of the largest
system in the combined distribution system.

(2) The requirements of this subpart for filtered systems apply to
systems required by National Primary Drinking Water Regulations to
provide filtration treatment, whether or not the system is currently
operating a filtration system.

(3) The requirements of this subpart for unfiltered systems apply only
to unfiltered systems that timely met and continue to meet the
filtration avoidance criteria in subparts H, P, and T of this part, as
applicable.

(c) Requirements. Systems subject to this subpart must comply with the
following requirements:

(1) Systems must conduct an initial and a second round of source water
monitoring for each plant that treats a surface water or GWUDI source.
This monitoring may include sampling for Cryptosporidium, E. coli, and
turbidity as described in §§141.701 through 141.706, to determine what
level, if any, of additional Cryptosporidium treatment they must
provide.

(2) Systems that plan to make a significant change to their disinfection
practice must develop disinfection profiles and calculate disinfection
benchmarks, as described in §§141.708 through 141.709.

(3) Filtered systems must determine their Cryptosporidium treatment bin
classification as described in §141.710 and provide additional
treatment for Cryptosporidium, if required, as described in §141.711.
All unfiltered systems must provide treatment for Cryptosporidium as
described in §141.712. Filtered and unfiltered systems must implement
Cryptosporidium treatment according to the schedule in §141.713.

(4) Systems with uncovered finished water storage facilities must comply
with the requirements to cover the facility or treat the discharge from
the facility as described in §141.714.

(5) Systems required to provide additional treatment for Cryptosporidium
must implement microbial toolbox options that are designed and operated
as described in §§141.715 through 141.720.

(6) Systems must comply with the applicable recordkeeping and reporting
requirements described in §§141.721 through 141.722.

(7) Systems must address significant deficiencies identified in sanitary
surveys performed by EPA as described in §141.723.

Source Water Monitoring Requirements

§ 141.701   Source water monitoring.

(a) Initial round of source water monitoring. Systems must conduct the
following monitoring on the schedule in paragraph (c) of this section
unless they meet the monitoring exemption criteria in paragraph (d) of
this section.

(1) Filtered systems serving at least 10,000 people must sample their
source water for Cryptosporidium, E. coli, and turbidity at least
monthly for 24 months.

(2) Unfiltered systems serving at least 10,000 people must sample their
source water for Cryptosporidium at least monthly for 24 months.

(3)(i) Filtered systems serving fewer than 10,000 people must sample
their source water for E. coli at least once every two weeks for 12
months.

(ii) A filtered system serving fewer than 10,000 people may avoid E.
coli monitoring if the system notifies the State that it will monitor
for Cryptosporidium as described in paragraph (a)(4) of this section.
The system must notify the State no later than 3 months prior to the
date the system is otherwise required to start E. coli monitoring under
§141.701(c).

(4) Filtered systems serving fewer than 10,000 people must sample their
source water for Cryptosporidium at least twice per month for 12 months
or at least monthly for 24 months if they meet one of the following,
based on monitoring conducted under paragraph (a)(3) of this section:

(i) For systems using lake/reservoir sources, the annual mean E. coli
concentration is greater than 10 E. coli /100 mL.

(ii) For systems using flowing stream sources, the annual mean E. coli
concentration is greater than 50 E. coli /100 mL.

(iii) The system does not conduct E. coli monitoring as described in
paragraph (a)(3) of this section.

(iv) Systems using ground water under the direct influence of surface
water (GWUDI) must comply with the requirements of paragraph (a)(4) of
this section based on the E. coli level that applies to the nearest
surface water body. If no surface water body is nearby, the system must
comply based on the requirements that apply to systems using
lake/reservoir sources.

(5) For filtered systems serving fewer than 10,000 people, the State may
approve monitoring for an indicator other than E. coli under paragraph
(a)(3) of this section. The State also may approve an alternative to the
E. coli concentration in paragraph (a)(4)(i), (ii) or (iv) of this
section to trigger Cryptosporidium monitoring. This approval by the
State must be provided to the system in writing and must include the
basis for the State's determination that the alternative indicator
and/or trigger level will provide a more accurate identification of
whether a system will exceed the Bin 1 Cryptosporidium level in
§141.710.

(6) Unfiltered systems serving fewer than 10,000 people must sample
their source water for Cryptosporidium at least twice per month for 12
months or at least monthly for 24 months.

(7) Systems may sample more frequently than required under this section
if the sampling frequency is evenly spaced throughout the monitoring
period.

(b) Second round of source water monitoring. Systems must conduct a
second round of source water monitoring that meets the requirements for
monitoring parameters, frequency, and duration described in paragraph
(a) of this section, unless they meet the monitoring exemption criteria
in paragraph (d) of this section. Systems must conduct this monitoring
on the schedule in paragraph (c) of this section.

(c) Monitoring schedule. Systems must begin the monitoring required in
paragraphs (a) and (b) of this section no later than the month beginning
with the date listed in this table:

Source Water Monitoring Starting Dates Table

Systems that serve . . .

Must begin the first round of source water monitoring no later than the
month

beginning . . .

And must begin the second round of source water monitoring no later than
the month beginning . . .

(1) At least 100,000 people

(i) October 1, 2006

(ii) April 1, 2015.

(2) From 50,000 to 99,999 people

(i) April 1, 2007

(ii) October 1, 2015.

(3) From 10,000 to 49,999 people

(i) April 1, 2008

(ii) October 1, 2016.

(4) Fewer than 10,000 and monitor for E. coli a

(i) October 1, 2008

(ii) October 1, 2017.

(5) Fewer than 10,000 and monitor for Cryptosporidium b

(i) April 1, 2010

(ii) April 1, 2019.

aApplies only to filtered systems.

bApplies to filtered systems that meet the conditions of paragraph
(a)(4) of this section and unfiltered systems.

(d) Monitoring avoidance. (1) Filtered systems are not required to
conduct source water monitoring under this subpart if the system will
provide a total of at least 5.5-log of treatment for Cryptosporidium,
equivalent to meeting the treatment requirements of Bin 4 in §141.711.

(2) Unfiltered systems are not required to conduct source water
monitoring under this subpart if the system will provide a total of at
least 3-log Cryptosporidium inactivation, equivalent to meeting the
treatment requirements for unfiltered systems with a mean
Cryptosporidium concentration of greater than 0.01 oocysts/L in
§141.712.

(3) If a system chooses to provide the level of treatment in paragraph
(d)(1) or (2) of this section, as applicable, rather than start source
water monitoring, the system must notify the State in writing no later
than the date the system is otherwise required to submit a sampling
schedule for monitoring under §141.702. Alternatively, a system may
choose to stop sampling at any point after it has initiated monitoring
if it notifies the State in writing that it will provide this level of
treatment. Systems must install and operate technologies to provide this
level of treatment by the applicable treatment compliance date in
§141.713.

(e) Plants operating only part of the year. Systems with subpart H
plants that operate for only part of the year must conduct source water
monitoring in accordance with this subpart, but with the following
modifications:

(1) Systems must sample their source water only during the months that
the plant operates unless the State specifies another monitoring period
based on plant operating practices.

(2) Systems with plants that operate less than six months per year and
that monitor for Cryptosporidium must collect at least six
Cryptosporidium samples per year during each of two years of monitoring.
Samples must be evenly spaced throughout the period the plant operates.

(f)(1) New sources. A system that begins using a new source of surface
water or GWUDI after the system is required to begin monitoring under
paragraph (c) of this section must monitor the new source on a schedule
the State approves. Source water monitoring must meet the requirements
of this subpart. The system must also meet the bin classification and
Cryptosporidium treatment requirements of §§141.710 and 141.711 or
§141.712, as applicable, for the new source on a schedule the State
approves.

(2) The requirements of §141.701(f) apply to subpart H systems that
begin operation after the monitoring start date applicable to the
system's size under paragraph (c) of this section.

(3) The system must begin a second round of source water monitoring no
later than 6 years following initial bin classification under §141.710
or determination of the mean Cryptosporidium level under §141.712, as
applicable.

(g) Failure to collect any source water sample required under this
section in accordance with the sampling schedule, sampling location,
analytical method, approved laboratory, and reporting requirements of
§§141.702 through 141.706 is a monitoring violation.

(h) Grandfathering monitoring data. Systems may use (grandfather)
monitoring data collected prior to the applicable monitoring start date
in paragraph (c) of this section to meet the initial source water
monitoring requirements in paragraph (a) of this section. Grandfathered
data may substitute for an equivalent number of months at the end of the
monitoring period. All data submitted under this paragraph must meet the
requirements in §141.707.

§ 141.702   Sampling schedules.

(a) Systems required to conduct source water monitoring under §141.701
must submit a sampling schedule that specifies the calendar dates when
the system will collect each required sample.

(1) Systems must submit sampling schedules no later than 3 months prior
to the applicable date listed in §141.701(c) for each round of required
monitoring.

(2)(i) Systems serving at least 10,000 people must submit their sampling
schedule for the initial round of source water monitoring under
§141.701(a) to EPA electronically at https://intranet.epa.gov/lt2/. 

(ii) If a system is unable to submit the sampling schedule
electronically, the system may use an alternative approach for
submitting the sampling schedule that EPA approves.

(3) Systems serving fewer than 10,000 people must submit their sampling
schedules for the initial round of source water monitoring §141.701(a)
to the State.

(4) Systems must submit sampling schedules for the second round of
source water monitoring §141.701(b) to the State.

(5) If EPA or the State does not respond to a system regarding its
sampling schedule, the system must sample at the reported schedule.

(b) Systems must collect samples within two days before or two days
after the dates indicated in their sampling schedule (i.e., within a
five-day period around the schedule date) unless one of the conditions
of paragraph (b)(1) or (2) of this section applies.

(1) If an extreme condition or situation exists that may pose danger to
the sample collector, or that cannot be avoided and causes the system to
be unable to sample in the scheduled five-day period, the system must
sample as close to the scheduled date as is feasible unless the State
approves an alternative sampling date. The system must submit an
explanation for the delayed sampling date to the State concurrent with
the shipment of the sample to the laboratory.

(2)(i) If a system is unable to report a valid analytical result for a
scheduled sampling date due to equipment failure, loss of or damage to
the sample, failure to comply with the analytical method requirements,
including the quality control requirements in §141.704, or the failure
of an approved laboratory to analyze the sample, then the system must
collect a replacement sample.

(ii) The system must collect the replacement sample not later than 21
days after receiving information that an analytical result cannot be
reported for the scheduled date unless the system demonstrates that
collecting a replacement sample within this time frame is not feasible
or the State approves an alternative resampling date. The system must
submit an explanation for the delayed sampling date to the State
concurrent with the shipment of the sample to the laboratory.

(c) Systems that fail to meet the criteria of paragraph (b) of this
section for any source water sample required under §141.701 must revise
their sampling schedules to add dates for collecting all missed samples.
Systems must submit the revised schedule to the State for approval prior
to when the system begins collecting the missed samples.

§ 141.703   Sampling locations.

(a) Systems required to conduct source water monitoring under §141.701
must collect samples for each plant that treats a surface water or GWUDI
source. Where multiple plants draw water from the same influent, such as
the same pipe or intake, the State may approve one set of monitoring
results to be used to satisfy the requirements of §141.701 for all
plants.

(b)(1) Systems must collect source water samples prior to chemical
treatment, such as coagulants, oxidants and disinfectants, unless the
system meets the condition of paragraph (b)(2) of this section.

(2) The State may approve a system to collect a source water sample
after chemical treatment. To grant this approval, the State must
determine that collecting a sample prior to chemical treatment is not
feasible for the system and that the chemical treatment is unlikely to
have a significant adverse effect on the analysis of the sample.

(c) Systems that recycle filter backwash water must collect source water
samples prior to the point of filter backwash water addition.

(d) Bank filtration. (1) Systems that receive Cryptosporidium treatment
credit for bank filtration under §141.173(b) or §141.552(a), as
applicable, must collect source water samples in the surface water prior
to bank filtration.

(2) Systems that use bank filtration as pretreatment to a filtration
plant must collect source water samples from the well (i.e., after bank
filtration). Use of bank filtration during monitoring must be consistent
with routine operational practice. Systems collecting samples after a
bank filtration process may not receive treatment credit for the bank
filtration under §141.717(c).

(e) Multiple sources. Systems with plants that use multiple water
sources, including multiple surface water sources and blended surface
water and ground water sources, must collect samples as specified in
paragraph (e)(1) or (2) of this section. The use of multiple sources
during monitoring must be consistent with routine operational practice.

(1) If a sampling tap is available where the sources are combined prior
to treatment, systems must collect samples from the tap.

(2) If a sampling tap where the sources are combined prior to treatment
is not available, systems must collect samples at each source near the
intake on the same day and must follow either paragraph (e)(2)(i) or
(ii) of this section for sample analysis.

(i) Systems may composite samples from each source into one sample prior
to analysis. The volume of sample from each source must be weighted
according to the proportion of the source in the total plant flow at the
time the sample is collected.

(ii) Systems may analyze samples from each source separately and
calculate a weighted average of the analysis results for each sampling
date. The weighted average must be calculated by multiplying the
analysis result for each source by the fraction the source contributed
to total plant flow at the time the sample was collected and then
summing these values.

(f) Additional Requirements. Systems must submit a description of their
sampling location(s) to the State at the same time as the sampling
schedule required under §141.702. This description must address the
position of the sampling location in relation to the system's water
source(s) and treatment processes, including pretreatment, points of
chemical treatment, and filter backwash recycle. If the State does not
respond to a system regarding sampling location(s), the system must
sample at the reported location(s).

§ 141.704   Analytical methods.

(a) Cryptosporidium. Systems must analyze for Cryptosporidium using
Method 1623: Cryptosporidium and Giardia in Water by Filtration/IMS/FA,
2005, United States Environmental Protection Agency,
EPA–815-R–05–002 or Method 1622: Cryptosporidium in Water by
Filtration/IMS/FA, 2005, United States Environmental Protection Agency,
EPA–815–R–05–001, which 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. You may
obtain a copy of these methods online from
http://www.epa.gov/safewater/disinfection/lt2 or from the United States
Environmental Protection Agency, Office of Ground Water and Drinking
Water, 1201 Constitution Ave., NW, Washington, DC 20460 (Telephone:
800–426–4791). You may inspect a copy at the Water Docket in the EPA
Docket Center, 1301 Constitution Ave., NW, Washington, DC, (Telephone:
202–566–2426) 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: h
ttp://www.archives.gov/federal_register/code_of_federal_regulations/ibr_
locations.html. 

(1) Systems must analyze at least a 10 L sample or a packed pellet
volume of at least 2 mL as generated by the methods listed in paragraph
(a) of this section. Systems unable to process a 10 L sample must
analyze as much sample volume as can be filtered by two filters approved
by EPA for the methods listed in paragraph (a) of this section, up to a
packed pellet volume of at least 2 mL.

(2)(i) Matrix spike (MS) samples, as required by the methods in
paragraph (a) of this section, must be spiked and filtered by a
laboratory approved for Cryptosporidium analysis under §141.705.

(ii) If the volume of the MS sample is greater than 10 L, the system may
filter all but 10 L of the MS sample in the field, and ship the filtered
sample and the remaining 10 L of source water to the laboratory. In this
case, the laboratory must spike the remaining 10 L of water and filter
it through the filter used to collect the balance of the sample in the
field.

(3) Flow cytometer-counted spiking suspensions must be used for MS
samples and ongoing precision and recovery (OPR) samples.

(b) E. coli. Systems must use methods for enumeration of E. coli in
source water approved in §136.3(a) of this title.

(1) The time from sample collection to initiation of analysis may not
exceed 30 hours unless the system meets the condition of paragraph
(b)(2) of this section.

(2) The State may approve on a case-by-case basis the holding of an E.
coli sample for up to 48 hours between sample collection and initiation
of analysis if the State determines that analyzing an E. coli sample
within 30 hours is not feasible. E. coli samples held between 30 to 48
hours must be analyzed by the Colilert reagent version of Standard
Method 9223B as listed in §136.3(a) of this title.

(3) Systems must maintain samples between 0 °C and 10 °C during
storage and transit to the laboratory.

(c) Turbidity. Systems must use methods for turbidity measurement
approved in §141.74(a)(1).

§ 141.705   Approved laboratories.

(a) Cryptosporidium. Systems must have Cryptosporidium samples analyzed
by a laboratory that is approved under EPA's Laboratory Quality
Assurance Evaluation Program for Analysis of Cryptosporidium in Water or
a laboratory that has been certified for Cryptosporidium analysis by an
equivalent State laboratory certification program.

(b) E. coli. Any laboratory certified by the EPA, the National
Environmental Laboratory Accreditation Conference or the State for total
coliform or fecal coliform analysis under §141.74 is approved for E.
coli analysis under this subpart when the laboratory uses the same
technique for E. coli that the laboratory uses for §141.74.

(c) Turbidity. Measurements of turbidity must be made by a party
approved by the State.

§ 141.706   Reporting source water monitoring results.

(a) Systems must report results from the source water monitoring
required under §141.701 no later than 10 days after the end of the
first month following the month when the sample is collected.

(b)(1) All systems serving at least 10,000 people must report the
results from the initial source water monitoring required under
§141.701(a) to EPA electronically at https://intranet.epa.gov/lt2/. 

(2) If a system is unable to report monitoring results electronically,
the system may use an alternative approach for reporting monitoring
results that EPA approves.

(c) Systems serving fewer than 10,000 people must report results from
the initial source water monitoring required under §141.701(a) to the
State.

(d) All systems must report results from the second round of source
water monitoring required under §141.701(b) to the State.

(e) Systems must report the applicable information in paragraphs (e)(1)
and (2) of this section for the source water monitoring required under
§141.701.

(1) Systems must report the following data elements for each
Cryptosporidium analysis:

Data element.

1. PWS ID.

2. Facility ID.

3. Sample collection date.

4. Sample type (field or matrix spike).

5. Sample volume filtered (L), to nearest 1/4 L.

6. Was 100% of filtered volume examined.

7. Number of oocysts counted.

(i) For matrix spike samples, systems must also report the sample volume
spiked and estimated number of oocysts spiked. These data are not
required for field samples.

(ii) For samples in which less than 10 L is filtered or less than 100%
of the sample volume is examined, systems must also report the number of
filters used and the packed pellet volume.

(iii) For samples in which less than 100% of sample volume is examined,
systems must also report the volume of resuspended concentrate and
volume of this resuspension processed through immunomagnetic separation.

(2) Systems must report the following data elements for each E. coli
analysis:

Data element.

1. PWS ID.

2. Facility ID.

3. Sample collection date.

4. Analytical method number.

5. Method type.

6. Source type (flowing stream, lake/reservoir, GWUDI).

7. E. coli /100 mL.

8. Turbidity.1

1Systems serving fewer than 10,000 people that are not required to
monitor for turbidity under §141.701 are not required to report
turbidity with their E. coli results.

§ 141.707   Grandfathering previously collected data.

(a)(1) Systems may comply with the initial source water monitoring
requirements of §141.701(a) by grandfathering sample results collected
before the system is required to begin monitoring (i.e., previously
collected data). To be grandfathered, the sample results and analysis
must meet the criteria in this section and the State must approve.

(2) A filtered system may grandfather Cryptosporidium samples to meet
the requirements of §141.701(a) when the system does not have
corresponding E. coli and turbidity samples. A system that grandfathers
Cryptosporidium samples without E. coli and turbidity samples is not
required to collect E. coli and turbidity samples when the system
completes the requirements for Cryptosporidium monitoring under
§141.701(a).

(b) E. coli sample analysis. The analysis of E. coli samples must meet
the analytical method and approved laboratory requirements of
§§141.704 through 141.705.

(c) Cryptosporidium sample analysis. The analysis of Cryptosporidium
samples must meet the criteria in this paragraph.

(1) Laboratories analyzed Cryptosporidium samples using one of the
analytical methods in paragraphs (c)(1)(i) through (vi) of this section,
which 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. You may obtain a copy of these methods
on-line from the United States Environmental Protection Agency, Office
of Ground Water and Drinking Water, 1201 Constitution Ave, NW,
Washington, DC 20460 (Telephone: 800–426–4791). You may inspect a
copy at the Water Docket in the EPA Docket Center, 1301 Constitution
Ave., NW, Washington, DC, (Telephone: 202–566–2426) 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. 

(i) Method 1623: Cryptosporidium and Giardia in Water by
Filtration/IMS/FA, 2005, United States Environmental Protection Agency,
EPA–815–R–05–002.

(ii) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 2005,
United States Environmental Protection Agency, EPA–815–R–05–001.

(iii) Method 1623: Cryptosporidium and Giardia in Water by
Filtration/IMS/FA, 2001, United States Environmental Protection Agency,
EPA–821–R–01–025.

(iv) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 2001,
United States Environmental Protection Agency,
EPA–821–-R–01–026.

(v) Method 1623: Cryptosporidium and Giardia in Water by
Filtration/IMS/FA, 1999, United States Environmental Protection Agency,
EPA–821–R–99–006.

(vi) Method 1622: Cryptosporidium in Water by Filtration/IMS/FA, 1999,
United States Environmental Protection Agency, EPA–821–R–99–001.

(2) For each Cryptosporidium sample, the laboratory analyzed at least 10
L of sample or at least 2 mL of packed pellet or as much volume as could
be filtered by 2 filters that EPA approved for the methods listed in
paragraph (c)(1) of this section.

(d) Sampling location. The sampling location must meet the conditions in
§141.703.

(e) Sampling frequency. Cryptosporidium samples were collected no less
frequently than each calendar month on a regular schedule, beginning no
earlier than January 1999. Sample collection intervals may vary for the
conditions specified in §141.702(b)(1) and (2) if the system provides
documentation of the condition when reporting monitoring results.

(1) The State may approve grandfathering of previously collected data
where there are time gaps in the sampling frequency if the system
conducts additional monitoring the State specifies to ensure that the
data used to comply with the initial source water monitoring
requirements of §141.701(a) are seasonally representative and unbiased.

(2) Systems may grandfather previously collected data where the sampling
frequency within each month varied. If the Cryptosporidium sampling
frequency varied, systems must follow the monthly averaging procedure in
§141.710(b)(5) or §141.712(a)(3), as applicable, when calculating the
bin classification for filtered systems or the mean Cryptosporidium
concentration for unfiltered systems.

(f) Reporting monitoring results for grandfathering. Systems that
request to grandfather previously collected monitoring results must
report the following information by the applicable dates listed in this
paragraph. Systems serving at least 10,000 people must report this
information to EPA unless the State approves reporting to the State
rather than EPA. Systems serving fewer than 10,000 people must report
this information to the State.

(1) Systems must report that they intend to submit previously collected
monitoring results for grandfathering. This report must specify the
number of previously collected results the system will submit, the dates
of the first and last sample, and whether a system will conduct
additional source water monitoring to meet the requirements of
§141.701(a). Systems must report this information no later than the
date the sampling schedule under §141.702 is required.

(2) Systems must report previously collected monitoring results for
grandfathering, along with the associated documentation listed in
paragraphs (f)(2)(i) through (iv) of this section, no later than two
months after the applicable date listed in §141.701(c).

(i) For each sample result, systems must report the applicable data
elements in §141.706.

(ii) Systems must certify that the reported monitoring results include
all results the system generated during the time period beginning with
the first reported result and ending with the final reported result.
This applies to samples that were collected from the sampling location
specified for source water monitoring under this subpart, not spiked,
and analyzed using the laboratory's routine process for the analytical
methods listed in this section.

(iii) Systems must certify that the samples were representative of a
plant's source water(s) and the source water(s) have not changed.
Systems must report a description of the sampling location(s), which
must address the position of the sampling location in relation to the
system's water source(s) and treatment processes, including points of
chemical addition and filter backwash recycle.

(iv) For Cryptosporidium samples, the laboratory or laboratories that
analyzed the samples must provide a letter certifying that the quality
control criteria specified in the methods listed in paragraph (c)(1) of
this section were met for each sample batch associated with the reported
results. Alternatively, the laboratory may provide bench sheets and
sample examination report forms for each field, matrix spike, IPR, OPR,
and method blank sample associated with the reported results.

(g) If the State determines that a previously collected data set
submitted for grandfathering was generated during source water
conditions that were not normal for the system, such as a drought, the
State may disapprove the data. Alternatively, the State may approve the
previously collected data if the system reports additional source water
monitoring data, as determined by the State, to ensure that the data set
used under §141.710 or §141.712 represents average source water
conditions for the system.

(h) If a system submits previously collected data that fully meet the
number of samples required for initial source water monitoring under
§141.701(a) and some of the data are rejected due to not meeting the
requirements of this section, systems must conduct additional monitoring
to replace rejected data on a schedule the State approves. Systems are
not required to begin this additional monitoring until two months after
notification that data have been rejected and additional monitoring is
necessary.

Disinfection Profiling and Benchmarking Requirements

§ 141.708   Requirements when making a significant change in
disinfection practice.

(a) Following the completion of initial source water monitoring under
§141.701(a), a system that plans to make a significant change to its
disinfection practice, as defined in paragraph (b) of this section, must
develop disinfection profiles and calculate disinfection benchmarks for
Giardia lamblia and viruses as described in §141.709. Prior to changing
the disinfection practice, the system must notify the State and must
include in this notice the information in paragraphs (a)(1) through (3)
of this section.

(1) A completed disinfection profile and disinfection benchmark for
Giardia lamblia and viruses as described in §141.709.

(2) A description of the proposed change in disinfection practice.

(3) An analysis of how the proposed change will affect the current level
of disinfection.

(b) Significant changes to disinfection practice are defined as follows:

(1) Changes to the point of disinfection;

(2) Changes to the disinfectant(s) used in the treatment plant;

(3) Changes to the disinfection process; or

(4) Any other modification identified by the State as a significant
change to disinfection practice.

§ 141.709   Developing the disinfection profile and benchmark.

(a) Systems required to develop disinfection profiles under §141.708
must follow the requirements of this section. Systems must monitor at
least weekly for a period of 12 consecutive months to determine the
total log inactivation for Giardia lamblia and viruses. If systems
monitor more frequently, the monitoring frequency must be evenly spaced.
Systems that operate for fewer than 12 months per year must monitor
weekly during the period of operation. Systems must determine log
inactivation for Giardia lamblia through the entire plant, based on
CT99.9values in Tables 1.1 through 1.6, 2.1 and 3.1 of §141.74(b) as
applicable. Systems must determine log inactivation for viruses through
the entire treatment plant based on a protocol approved by the State.

(b) Systems with a single point of disinfectant application prior to the
entrance to the distribution system must conduct the monitoring in
paragraphs (b)(1) through (4) of this section. Systems with more than
one point of disinfectant application must conduct the monitoring in
paragraphs (b)(1) through (4) of this section for each disinfection
segment. Systems must monitor the parameters necessary to determine the
total inactivation ratio, using analytical methods in §141.74(a).

(1) For systems using a disinfectant other than UV, the temperature of
the disinfected water must be measured at each residual disinfectant
concentration sampling point during peak hourly flow or at an
alternative location approved by the State.

(2) For systems using chlorine, the pH of the disinfected water must be
measured at each chlorine residual disinfectant concentration sampling
point during peak hourly flow or at an alternative location approved by
the State.

(3) The disinfectant contact time(s) (t) must be determined during peak
hourly flow.

(4) The residual disinfectant concentration(s) (C) of the water before
or at the first customer and prior to each additional point of
disinfectant application must be measured during peak hourly flow.

(c) In lieu of conducting new monitoring under paragraph (b) of this
section, systems may elect to meet the requirements of paragraphs (c)(1)
or (2) of this section.

(1) Systems that have at least one year of existing data that are
substantially equivalent to data collected under the provisions of
paragraph (b) of this section may use these data to develop disinfection
profiles as specified in this section if the system has neither made a
significant change to its treatment practice nor changed sources since
the data were collected. Systems may develop disinfection profiles using
up to three years of existing data.

(2) Systems may use disinfection profile(s) developed under §141.172 or
§§141.530 through 141.536 in lieu of developing a new profile if the
system has neither made a significant change to its treatment practice
nor changed sources since the profile was developed. Systems that have
not developed a virus profile under §141.172 or §§141.530 through
141.536 must develop a virus profile using the same monitoring data on
which the Giardia lamblia profile is based.

(d) Systems must calculate the total inactivation ratio for Giardia
lamblia as specified in paragraphs (d)(1) through (3) of this section.

(1) Systems using only one point of disinfectant application may
determine the total inactivation ratio for the disinfection segment
based on either of the methods in paragraph (d)(1)(i) or (ii) of this
section.

(i) Determine one inactivation ratio (CTcalc/CT99.9) before or at the
first customer during peak hourly flow.

(ii) Determine successive CTcalc/CT99.9values, representing sequential
inactivation ratios, between the point of disinfectant application and a
point before or at the first customer during peak hourly flow. The
system must calculate the total inactivation ratio by determining
(CTcalc/CT99.9) for each sequence and then adding the (CTcalc/CT99.9)
values together to determine (Σ (CTcalc/CT99.9)).

(2) Systems using more than one point of disinfectant application before
the first customer must determine the CT value of each disinfection
segment immediately prior to the next point of disinfectant application,
or for the final segment, before or at the first customer, during peak
hourly flow. The (CTcalc/CT99.9) value of each segment and (Σ
(CTcalc/CT99.9)) must be calculated using the method in paragraph
(d)(1)(ii) of this section.

(3) The system must determine the total logs of inactivation by
multiplying the value calculated in paragraph (d)(1) or (d)(2) of this
section by 3.0.

(4) Systems must calculate the log of inactivation for viruses using a
protocol approved by the State.

(e) Systems must use the procedures specified in paragraphs (e)(1) and
(2) of this section to calculate a disinfection benchmark.

(1) For each year of profiling data collected and calculated under
paragraphs (a) through (d) of this section, systems must determine the
lowest mean monthly level of both Giardia lamblia and virus
inactivation. Systems must determine the mean Giardia lamblia and virus
inactivation for each calendar month for each year of profiling data by
dividing the sum of daily or weekly Giardia lamblia and virus log
inactivation by the number of values calculated for that month.

(2) The disinfection benchmark is the lowest monthly mean value (for
systems with one year of profiling data) or the mean of the lowest
monthly mean values (for systems with more than one year of profiling
data) of Giardia lamblia and virus log inactivation in each year of
profiling data.

Treatment Technique Requirements

§ 141.710   Bin classification for filtered systems.

(a) Following completion of the initial round of source water monitoring
required under §141.701(a), filtered systems must calculate an initial
Cryptosporidium bin concentration for each plant for which monitoring
was required. Calculation of the bin concentration must use the
Cryptosporidium results reported under §141.701(a) and must follow the
procedures in paragraphs (b)(1) through (5) of this section.

(b)(1) For systems that collect a total of at least 48 samples, the bin
concentration is equal to the arithmetic mean of all sample
concentrations.

(2) For systems that collect a total of at least 24 samples, but not
more than 47 samples, the bin concentration is equal to the highest
arithmetic mean of all sample concentrations in any 12 consecutive
months during which Cryptosporidium samples were collected.

(3) For systems that serve fewer than 10,000 people and monitor for
Cryptosporidium for only one year (i.e., collect 24 samples in 12
months), the bin concentration is equal to the arithmetic mean of all
sample concentrations.

(4) For systems with plants operating only part of the year that monitor
fewer than 12 months per year under §141.701(e), the bin concentration
is equal to the highest arithmetic mean of all sample concentrations
during any year of Cryptosporidium monitoring.

(5) If the monthly Cryptosporidium sampling frequency varies, systems
must first calculate a monthly average for each month of monitoring.
Systems must then use these monthly average concentrations, rather than
individual sample concentrations, in the applicable calculation for bin
classification in paragraphs (b)(1) through (4) of this section.

(c) Filtered systems must determine their initial bin classification
from the following table and using the Cryptosporidium bin concentration
calculated under paragraphs (a)–(b) of this section:

Bin Classification Table for Filtered Systems

For systems that are:

With a Cryptosporidium bin concentration of . . .1

The bin classification is . . .

. . . required to monitor for Cryptosporidium under §141.701

Cryptosporidium <0.075 oocyst/L

Bin 1.

  

  0.075 oocysts/L ≤Cryptosporidium <1.0 oocysts/L

Bin 2.

  

  1.0 oocysts/L ≤Cryptosporidium <3.0 oocysts/L

Bin 3.

  

   Cryptosporidium ≥3.0 oocysts/L

Bin 4.

. . . serving fewer than 10,000 people and NOT required to monitor for
Cryptosporidium under §141.701(a)(4)

NA

Bin 1.

1Based on calculations in paragraph (a) or (d) of this section, as
applicable.

(d) Following completion of the second round of source water monitoring
required under §141.701(b), filtered systems must recalculate their
Cryptosporidium bin concentration using the Cryptosporidium results
reported under §141.701(b) and following the procedures in paragraphs
(b)(1) through (4) of this section. Systems must then redetermine their
bin classification using this bin concentration and the table in
paragraph (c) of this section.

(e)(1) Filtered systems must report their initial bin classification
under paragraph (c) of this section to the State for approval no later
than 6 months after the system is required to complete initial source
water monitoring based on the schedule in §141.701(c).

(2) Systems must report their bin classification under paragraph (d) of
this section to the State for approval no later than 6 months after the
system is required to complete the second round of source water
monitoring based on the schedule in §141.701(c).

(3) The bin classification report to the State must include a summary of
source water monitoring data and the calculation procedure used to
determine bin classification.

(f) Failure to comply with the conditions of paragraph (e) of this
section is a violation of the treatment technique requirement.

§ 141.711   Filtered system additional Cryptosporidium treatment
requirements.

(a) Filtered systems must provide the level of additional treatment for
Cryptosporidium specified in this paragraph based on their bin
classification as determined under §141.710 and according to the
schedule in §141.713.

If the system bin classification is . . .

And the system uses the following filtration treatment in full
compliance with subparts H, P, and T of this part (as applicable), then
the additional Cryptosporidium treatment requirements are . . .

Conventional filtration treatment

(including softening)

Direct filtration

Slow sand or diatomaceous earth filtration

Alternative filtration technologies

Bin 1

No additional treatment

No additional treatment

No additional treatment

No additional treatment.

Bin 2

1-log treatment

1.5-log treatment

1-log treatment

(1)

Bin 3

2-log treatment

2.5-log treatment

2-log treatment

(2)

Bin 4

2.5-log treatment

3-log treatment

2.5-log treatment

(3)

1As determined by the State such that the total Cryptosporidium removal
and inactivation is at least 4.0-log.

2As determined by the State such that the total Cryptosporidium removal
and inactivation is at least 5.0-log.

3As determined by the State such that the total Cryptosporidium removal
and inactivation is at least 5.5-log.

(b)(1) Filtered systems must use one or more of the treatment and
management options listed in §141.715, termed the microbial toolbox, to
comply with the additional Cryptosporidium treatment required in
paragraph (a) of this section.

(2) Systems classified in Bin 3 and Bin 4 must achieve at least 1-log of
the additional Cryptosporidium treatment required under paragraph (a) of
this section using either one or a combination of the following: bag
filters, bank filtration, cartridge filters, chlorine dioxide,
membranes, ozone, or UV, as described in §§141.716 through 141.720.

(c) Failure by a system in any month to achieve treatment credit by
meeting criteria in §§141.716 through 141.720 for microbial toolbox
options that is at least equal to the level of treatment required in
paragraph (a) of this section is a violation of the treatment technique
requirement.

(d) If the State determines during a sanitary survey or an equivalent
source water assessment that after a system completed the monitoring
conducted under §141.701(a) or §141.701(b), significant changes
occurred in the system's watershed that could lead to increased
contamination of the source water by Cryptosporidium, the system must
take actions specified by the State to address the contamination. These
actions may include additional source water monitoring and/or
implementing microbial toolbox options listed in §141.715.

§ 141.712   Unfiltered system Cryptosporidium treatment
requirements.

(a) Determination of mean Cryptosporidium level. (1) Following
completion of the initial source water monitoring required under
§141.701(a), unfiltered systems must calculate the arithmetic mean of
all Cryptosporidium sample concentrations reported under §141.701(a).
Systems must report this value to the State for approval no later than 6
months after the month the system is required to complete initial source
water monitoring based on the schedule in §141.701(c).

(2) Following completion of the second round of source water monitoring
required under §141.701(b), unfiltered systems must calculate the
arithmetic mean of all Cryptosporidium sample concentrations reported
under §141.701(b). Systems must report this value to the State for
approval no later than 6 months after the month the system is required
to complete the second round of source water monitoring based on the
schedule in §141.701(c).

(3) If the monthly Cryptosporidium sampling frequency varies, systems
must first calculate a monthly average for each month of monitoring.
Systems must then use these monthly average concentrations, rather than
individual sample concentrations, in the calculation of the mean
Cryptosporidium level in paragraphs (a)(1) or (2) of this section.

(4) The report to the State of the mean Cryptosporidium levels
calculated under paragraphs (a)(1) and (2) of this section must include
a summary of the source water monitoring data used for the calculation.

(5) Failure to comply with the conditions of paragraph (a) of this
section is a violation of the treatment technique requirement.

(b) Cryptosporidium inactivation requirements. Unfiltered systems must
provide the level of inactivation for Cryptosporidium specified in this
paragraph, based on their mean Cryptosporidium levels as determined
under paragraph (a) of this section and according to the schedule in
§141.713.

(1) Unfiltered systems with a mean Cryptosporidium level of 0.01
oocysts/L or less must provide at least 2-log Cryptosporidium
inactivation.

(2) Unfiltered systems with a mean Cryptosporidium level of greater than
0.01 oocysts/L must provide at least 3-log Cryptosporidium inactivation.

(c) Inactivation treatment technology requirements. Unfiltered systems
must use chlorine dioxide, ozone, or UV as described in §141.720 to
meet the Cryptosporidium inactivation requirements of this section.

(1) Systems that use chlorine dioxide or ozone and fail to achieve the
Cryptosporidium inactivation required in paragraph (b) of this section
on more than one day in the calendar month are in violation of the
treatment technique requirement.

(2) Systems that use UV light and fail to achieve the Cryptosporidium
inactivation required in paragraph (b) of this section by meeting the
criteria in §141.720(d)(3)(ii) are in violation of the treatment
technique requirement.

(d) Use of two disinfectants. Unfiltered systems must meet the combined
Cryptosporidium inactivation requirements of this section and Giardia
lamblia and virus inactivation requirements of §141.72(a) using a
minimum of two disinfectants, and each of two disinfectants must
separately achieve the total inactivation required for either
Cryptosporidium, Giardia lamblia, or viruses.

§ 141.713   Schedule for compliance with Cryptosporidium treatment
requirements.

(a) Following initial bin classification under §141.710(c), filtered
systems must provide the level of treatment for Cryptosporidium required
under §141.711 according to the schedule in paragraph (c) of this
section.

(b) Following initial determination of the mean Cryptosporidium level
under §141.712(a)(1), unfiltered systems must provide the level of
treatment for Cryptosporidium required under §141.712 according to the
schedule in paragraph (c) of this section.

(c) Cryptosporidium treatment compliance dates. 

Cryptosporidium Treatment Compliance Dates Table

Systems that serve . . .

Must comply with Cryptosporidium treatment requirements no later than .
. .a

(1) At least 100,000 people

(i) April 1, 2012.

(2) From 50,000 to 99,999 people

(i) October 1, 2012.

(3) From 10,000 to 49,999 people

(i) October 1, 2013.

(4) Fewer than 10,000 people

(i) October 1, 2014.

aStates may allow up to an additional two years for complying with the
treatment requirement for systems making capital improvements.

(d) If the bin classification for a filtered system changes following
the second round of source water monitoring, as determined under
§141.710(d), the system must provide the level of treatment for
Cryptosporidium required under §141.711 on a schedule the State
approves.

(e) If the mean Cryptosporidium level for an unfiltered system changes
following the second round of monitoring, as determined under
§141.712(a)(2), and if the system must provide a different level of
Cryptosporidium treatment under §141.712 due to this change, the system
must meet this treatment requirement on a schedule the State approves.

§ 141.714   Requirements for uncovered finished water storage
facilities.

(a) Systems using uncovered finished water storage facilities must
comply with the conditions of this section.

(b) Systems must notify the State of the use of each uncovered finished
water storage facility no later than April 1, 2008.

(c) Systems must meet the conditions of paragraph (c)(1) or (2) of this
section for each uncovered finished water storage facility or be in
compliance with a State-approved schedule to meet these conditions no
later than April 1, 2009.

(1) Systems must cover any uncovered finished water storage facility.

(2) Systems must treat the discharge from the uncovered finished water
storage facility to the distribution system to achieve inactivation
and/or removal of at least 4-log virus, 3-log Giardia lamblia, and 2-log
Cryptosporidium using a protocol approved by the State.

(d) Failure to comply with the requirements of this section is a
violation of the treatment technique requirement.

Requirements for Microbial Toolbox Components

§ 141.715   Microbial toolbox options for meeting Cryptosporidium
treatment requirements.

(a)(1) Systems receive the treatment credits listed in the table in
paragraph (b) of this section by meeting the conditions for microbial
toolbox options described in §§141.716 through 141.720. Systems apply
these treatment credits to meet the treatment requirements in §141.711
or §141.712, as applicable.

(2) Unfiltered systems are eligible for treatment credits for the
microbial toolbox options described in §141.720 only.

(b) The following table summarizes options in the microbial toolbox:

Microbial Toolbox Summary Table: Options, Treatment Credits and Criteria

Toolbox Option

Cryptosporidium treatment credit with design and implementation criteria

Source Protection and Management Toolbox Options

(1) Watershed control program

0.5-log credit for State-approved program comprising required elements,
annual program status report to State, and regular watershed survey.
Unfiltered systems are not eligible for credit. Specific criteria are in
§141.716(a).

(2) Alternative source/intake management

No prescribed credit. Systems may conduct simultaneous monitoring for
treatment bin classification at alternative intake locations or under
alternative intake management strategies. Specific criteria are in
§141.716(b).

Pre Filtration Toolbox Options

(3) Presedimentation basin with coagulation

0.5-log credit during any month that presedimentation basins achieve a
monthly mean reduction of 0.5-log or greater in turbidity or alternative
State-approved performance criteria. To be eligible, basins must be
operated continuously with coagulant addition and all plant flow must
pass through basins. Specific criteria are in §141.717(a).

(4) Two-stage lime softening

0.5-log credit for two-stage softening where chemical addition and
hardness precipitation occur in both stages. All plant flow must pass
through both stages. Single-stage softening is credited as equivalent to
conventional treatment. Specific criteria are in §141.717(b).

(5) Bank filtration

0.5-log credit for 25-foot setback; 1.0-log credit for 50-foot setback;
aquifer must be unconsolidated sand containing at least 10 percent
fines; average turbidity in wells must be less than 1 NTU. Systems using
wells followed by filtration when conducting source water monitoring
must sample the well to determine bin classification and are not
eligible for additional credit. Specific criteria are in §141.717(c).

Treatment Performance Toolbox Options

(6) Combined filter performance

0.5-log credit for combined filter effluent turbidity less than or equal
to 0.15 NTU in at least 95 percent of measurements each month. Specific
criteria are in §141.718(a).

(7) Individual filter performance

0.5-log credit (in addition to 0.5-log combined filter performance
credit) if individual filter effluent turbidity is less than or equal to
0.15 NTU in at least 95 percent of samples each month in each filter and
is never greater than 0.3 NTU in two consecutive measurements in any
filter. Specific criteria are in §141.718(b).

(8) Demonstration of performance

Credit awarded to unit process or treatment train based on a
demonstration to the State with a State- approved protocol. Specific
criteria are in §141.718(c).

Additional Filtration Toolbox Options

(9) Bag or cartridge filters (individual filters)

Up to 2-log credit based on the removal efficiency demonstrated during
challenge testing with a 1.0-log factor of safety. Specific criteria are
in §141.719(a).

(10) Bag or cartridge filters (in series)

Up to 2.5-log credit based on the removal efficiency demonstrated during
challenge testing with a 0.5-log factor of safety. Specific criteria are
in §141.719(a).

(11) Membrane filtration

Log credit equivalent to removal efficiency demonstrated in challenge
test for device if supported by direct integrity testing. Specific
criteria are in §141.719(b).

(12) Second stage filtration

0.5-log credit for second separate granular media filtration stage if
treatment train includes coagulation prior to first filter. Specific
criteria are in §141.719(c)

(13) Slow sand filters

2.5-log credit as a secondary filtration step; 3.0-log credit as a
primary filtration process. No prior chlorination for either option.
Specific criteria are in §141.719(d).

Inactivation Toolbox Options

(14) Chlorine dioxide

Log credit based on measured CT in relation to CT table. Specific
criteria in §141.720(b)

(15) Ozone

Log credit based on measured CT in relation to CT table. Specific
criteria in §141.720(b).

(16) UV

Log credit based on validated UV dose in relation to UV dose table;
reactor validation testing required to establish UV dose and associated
operating conditions. Specific criteria in §141.720(d).

§ 141.716   Source toolbox components.

(a) Watershed control program. Systems receive 0.5-log Cryptosporidium
treatment credit for implementing a watershed control program that meets
the requirements of this section.

(1) Systems that intend to apply for the watershed control program
credit must notify the State of this intent no later than two years
prior to the treatment compliance date applicable to the system in
§141.713.

(2) Systems must submit to the State a proposed watershed control plan
no later than one year before the applicable treatment compliance date
in §141.713. The State must approve the watershed control plan for the
system to receive watershed control program treatment credit. The
watershed control plan must include the elements in paragraphs (a)(2)(i)
through (iv) of this section.

(i) Identification of an “area of influence” outside of which the
likelihood of Cryptosporidium or fecal contamination affecting the
treatment plant intake is not significant. This is the area to be
evaluated in future watershed surveys under paragraph (a)(5)(ii) of this
section.

(ii) Identification of both potential and actual sources of
Cryptosporidium contamination and an assessment of the relative impact
of these sources on the system's source water quality.

(iii) An analysis of the effectiveness and feasibility of control
measures that could reduce Cryptosporidium loading from sources of
contamination to the system's source water.

(iv) A statement of goals and specific actions the system will undertake
to reduce source water Cryptosporidium levels. The plan must explain how
the actions are expected to contribute to specific goals, identify
watershed partners and their roles, identify resource requirements and
commitments, and include a schedule for plan implementation with
deadlines for completing specific actions identified in the plan.

(3) Systems with existing watershed control programs ( i.e., programs in
place on January 5, 2006) are eligible to seek this credit. Their
watershed control plans must meet the criteria in paragraph (a)(2) of
this section and must specify ongoing and future actions that will
reduce source water Cryptosporidium levels.

(4) If the State does not respond to a system regarding approval of a
watershed control plan submitted under this section and the system meets
the other requirements of this section, the watershed control program
will be considered approved and 0.5 log Cryptosporidium treatment credit
will be awarded unless and until the State subsequently withdraws such
approval.

(5) Systems must complete the actions in paragraphs (a)(5)(i) through
(iii) of this section to maintain the 0.5-log credit.

(i) Submit an annual watershed control program status report to the
State. The annual watershed control program status report must describe
the system's implementation of the approved plan and assess the adequacy
of the plan to meet its goals. It must explain how the system is
addressing any shortcomings in plan implementation, including those
previously identified by the State or as the result of the watershed
survey conducted under paragraph (a)(5)(ii) of this section. It must
also describe any significant changes that have occurred in the
watershed since the last watershed sanitary survey. If a system
determines during implementation that making a significant change to its
approved watershed control program is necessary, the system must notify
the State prior to making any such changes. If any change is likely to
reduce the level of source water protection, the system must also list
in its notification the actions the system will take to mitigate this
effect.

(ii) Undergo a watershed sanitary survey every three years for community
water systems and every five years for noncommunity water systems and
submit the survey report to the State. The survey must be conducted
according to State guidelines and by persons the State approves.

(A) The watershed sanitary survey must meet the following criteria:
encompass the region identified in the State-approved watershed control
plan as the area of influence; assess the implementation of actions to
reduce source water Cryptosporidium levels; and identify any significant
new sources of Cryptosporidium. 

(B) If the State determines that significant changes may have occurred
in the watershed since the previous watershed sanitary survey, systems
must undergo another watershed sanitary survey by a date the State
requires, which may be earlier than the regular date in paragraph
(a)(5)(ii) of this section.

(iii) The system must make the watershed control plan, annual status
reports, and watershed sanitary survey reports available to the public
upon request. These documents must be in a plain language style and
include criteria by which to evaluate the success of the program in
achieving plan goals. The State may approve systems to withhold from the
public portions of the annual status report, watershed control plan, and
watershed sanitary survey based on water supply security considerations.

(6) If the State determines that a system is not carrying out the
approved watershed control plan, the State may withdraw the watershed
control program treatment credit.

(b) Alternative source. (1) A system may conduct source water monitoring
that reflects a different intake location (either in the same source or
for an alternate source) or a different procedure for the timing or
level of withdrawal from the source (alternative source monitoring). If
the State approves, a system may determine its bin classification under
§141.710 based on the alternative source monitoring results.

(2) If systems conduct alternative source monitoring under paragraph
(b)(1) of this section, systems must also monitor their current plant
intake concurrently as described in §141.701.

(3) Alternative source monitoring under paragraph (b)(1) of this section
must meet the requirements for source monitoring to determine bin
classification, as described in §§141.701 through 141.706. Systems
must report the alternative source monitoring results to the State,
along with supporting information documenting the operating conditions
under which the samples were collected.

(4) If a system determines its bin classification under §141.710 using
alternative source monitoring results that reflect a different intake
location or a different procedure for managing the timing or level of
withdrawal from the source, the system must relocate the intake or
permanently adopt the withdrawal procedure, as applicable, no later than
the applicable treatment compliance date in §141.713.

§ 141.717   Pre-filtration treatment toolbox components.

(a) Presedimentation. Systems receive 0.5-log Cryptosporidium treatment
credit for a presedimentation basin during any month the process meets
the criteria in this paragraph.

(1) The presedimentation basin must be in continuous operation and must
treat the entire plant flow taken from a surface water or GWUDI source.

(2) The system must continuously add a coagulant to the presedimentation
basin.

(3) The presedimentation basin must achieve the performance criteria in
paragraph (3)(i) or (ii) of this section.

turbidity)−log10(monthly mean of daily effluent turbidity).

(ii) Complies with State-approved performance criteria that demonstrate
at least 0.5-log mean removal of micron-sized particulate material
through the presedimentation process.

(b) Two-stage lime softening. Systems receive an additional 0.5-log
Cryptosporidium treatment credit for a two-stage lime softening plant if
chemical addition and hardness precipitation occur in two separate and
sequential softening stages prior to filtration. Both softening stages
must treat the entire plant flow taken from a surface water or GWUDI
source.

(c) Bank filtration. Systems receive Cryptosporidium treatment credit
for bank filtration that serves as pretreatment to a filtration plant by
meeting the criteria in this paragraph. Systems using bank filtration
when they begin source water monitoring under §141.701(a) must collect
samples as described in §141.703(d) and are not eligible for this
credit.

(1) Wells with a ground water flow path of at least 25 feet receive
0.5-log treatment credit; wells with a ground water flow path of at
least 50 feet receive 1.0-log treatment credit. The ground water flow
path must be determined as specified in paragraph (c)(4) of this
section.

(2) Only wells in granular aquifers are eligible for treatment credit.
Granular aquifers are those comprised of sand, clay, silt, rock
fragments, pebbles or larger particles, and minor cement. A system must
characterize the aquifer at the well site to determine aquifer
properties. Systems must extract a core from the aquifer and demonstrate
that in at least 90 percent of the core length, grains less than 1.0 mm
in diameter constitute at least 10 percent of the core material.

(3) Only horizontal and vertical wells are eligible for treatment
credit.

(4) For vertical wells, the ground water flow path is the measured
distance from the edge of the surface water body under high flow
conditions (determined by the 100 year floodplain elevation boundary or
by the floodway, as defined in Federal Emergency Management Agency flood
hazard maps) to the well screen. For horizontal wells, the ground water
flow path is the measured distance from the bed of the river under
normal flow conditions to the closest horizontal well lateral screen.

(5) Systems must monitor each wellhead for turbidity at least once every
four hours while the bank filtration process is in operation. If monthly
average turbidity levels, based on daily maximum values in the well,
exceed 1 NTU, the system must report this result to the State and
conduct an assessment within 30 days to determine the cause of the high
turbidity levels in the well. If the State determines that microbial
removal has been compromised, the State may revoke treatment credit
until the system implements corrective actions approved by the State to
remediate the problem.

(6) Springs and infiltration galleries are not eligible for treatment
credit under this section, but are eligible for credit under
§141.718(c).

(7) Bank filtration demonstration of performance. The State may approve
Cryptosporidium treatment credit for bank filtration based on a
demonstration of performance study that meets the criteria in this
paragraph. This treatment credit may be greater than 1.0-log and may be
awarded to bank filtration that does not meet the criteria in paragraphs
(c)(1)–(5) of this section.

(i) The study must follow a State-approved protocol and must involve the
collection of data on the removal of Cryptosporidium or a surrogate for
Cryptosporidium and related hydrogeologic and water quality parameters
during the full range of operating conditions.

(ii) The study must include sampling both from the production well(s)
and from monitoring wells that are screened and located along the
shortest flow path between the surface water source and the production
well(s).

§ 141.718   Treatment performance toolbox components.

(a) Combined filter performance. Systems using conventional filtration
treatment or direct filtration treatment receive an additional 0.5-log
Cryptosporidium treatment credit during any month the system meets the
criteria in this paragraph. Combined filter effluent (CFE) turbidity
must be less than or equal to 0.15 NTU in at least 95 percent of the
measurements. Turbidity must be measured as described in §141.74(a) and
(c).

(b) Individual filter performance. Systems using conventional filtration
treatment or direct filtration treatment receive 0.5-log Cryptosporidium
treatment credit, which can be in addition to the 0.5-log credit under
paragraph (a) of this section, during any month the system meets the
criteria in this paragraph. Compliance with these criteria must be based
on individual filter turbidity monitoring as described in §141.174 or
§141.560, as applicable.

(1) The filtered water turbidity for each individual filter must be less
than or equal to 0.15 NTU in at least 95 percent of the measurements
recorded each month.

(2) No individual filter may have a measured turbidity greater than 0.3
NTU in two consecutive measurements taken 15 minutes apart.

(3) Any system that has received treatment credit for individual filter
performance and fails to meet the requirements of paragraph (b)(1) or
(2) of this section during any month does not receive a treatment
technique violation under §141.711(c) if the State determines the
following:

(i) The failure was due to unusual and short-term circumstances that
could not reasonably be prevented through optimizing treatment plant
design, operation, and maintenance.

(ii) The system has experienced no more than two such failures in any
calendar year.

(c) Demonstration of performance. The State may approve Cryptosporidium
treatment credit for drinking water treatment processes based on a
demonstration of performance study that meets the criteria in this
paragraph. This treatment credit may be greater than or less than the
prescribed treatment credits in §141.711 or §§141.717 through 141.720
and may be awarded to treatment processes that do not meet the criteria
for the prescribed credits.

(1) Systems cannot receive the prescribed treatment credit for any
toolbox box option in §§141.717 through 141.720 if that toolbox option
is included in a demonstration of performance study for which treatment
credit is awarded under this paragraph.

(2) The demonstration of performance study must follow a State-approved
protocol and must demonstrate the level of Cryptosporidium reduction the
treatment process will achieve under the full range of expected
operating conditions for the system.

(3) Approval by the State must be in writing and may include monitoring
and treatment performance criteria that the system must demonstrate and
report on an ongoing basis to remain eligible for the treatment credit.
The State may designate such criteria where necessary to verify that the
conditions under which the demonstration of performance credit was
approved are maintained during routine operation.

§ 141.719   Additional filtration toolbox components.

(a) Bag and cartridge filters. Systems receive Cryptosporidium treatment
credit of up to 2.0-log for individual bag or cartridge filters and up
to 2.5-log for bag or cartridge filters operated in series by meeting
the criteria in paragraphs (a)(1) through (10) of this section. To be
eligible for this credit, systems must report the results of challenge
testing that meets the requirements of paragraphs (a)(2) through (9) of
this section to the State. The filters must treat the entire plant flow
taken from a subpart H source.

(1) The Cryptosporidium treatment credit awarded to bag or cartridge
filters must be based on the removal efficiency demonstrated during
challenge testing that is conducted according to the criteria in
paragraphs (a)(2) through (a)(9) of this section. A factor of safety
equal to 1-log for individual bag or cartridge filters and 0.5-log for
bag or cartridge filters in series must be applied to challenge testing
results to determine removal credit. Systems may use results from
challenge testing conducted prior to January 5, 2006 if the prior
testing was consistent with the criteria specified in paragraphs (a)(2)
through (9) of this section.

(2) Challenge testing must be performed on full-scale bag or cartridge
filters, and the associated filter housing or pressure vessel, that are
identical in material and construction to the filters and housings the
system will use for removal of Cryptosporidium. Bag or cartridge filters
must be challenge tested in the same configuration that the system will
use, either as individual filters or as a series configuration of
filters.

(3) Challenge testing must be conducted using Cryptosporidium or a
surrogate that is removed no more efficiently than Cryptosporidium. The
microorganism or surrogate used during challenge testing is referred to
as the challenge particulate. The concentration of the challenge
particulate must be determined using a method capable of discreetly
quantifying the specific microorganism or surrogate used in the test;
gross measurements such as turbidity may not be used.

(4) The maximum feed water concentration that can be used during a
challenge test must be based on the detection limit of the challenge
particulate in the filtrate (i.e., filtrate detection limit) and must be
calculated using the following equation:

Maximum Feed Concentration = 1 × 104 × (Filtrate Detection Limit)

(5) Challenge testing must be conducted at the maximum design flow rate
for the filter as specified by the manufacturer.

(6) Each filter evaluated must be tested for a duration sufficient to
reach 100 percent of the terminal pressure drop, which establishes the
maximum pressure drop under which the filter may be used to comply with
the requirements of this subpart.

(7) Removal efficiency of a filter must be determined from the results
of the challenge test and expressed in terms of log removal values using
the following equation:

)−LOG10(Cp)

Where:

LRV = log removal value demonstrated during challenge testing; Cf= the
feed concentration measured during the challenge test; and Cp= the
filtrate concentration measured during the challenge test. In applying
this equation, the same units must be used for the feed and filtrate
concentrations. If the challenge particulate is not detected in the
filtrate, then the term Cpmust be set equal to the detection limit.

(8) Each filter tested must be challenged with the challenge particulate
during three periods over the filtration cycle: within two hours of
start-up of a new filter; when the pressure drop is between 45 and 55
percent of the terminal pressure drop; and at the end of the cycle after
the pressure drop has reached 100 percent of the terminal pressure drop.
An LRV must be calculated for each of these challenge periods for each
filter tested. The LRV for the filter (LRVfilter) must be assigned the
value of the minimum LRV observed during the three challenge periods for
that filter.

(9) If fewer than 20 filters are tested, the overall removal efficiency
for the filter product line must be set equal to the lowest
LRVfilteramong the filters tested. If 20 or more filters are tested, the
overall removal efficiency for the filter product line must be set equal
to the 10th percentile of the set of LRVfiltervalues for the various
filters tested. The percentile is defined by (i/(n+1)) where i is the
rank of n individual data points ordered lowest to highest. If
necessary, the 10th percentile may be calculated using linear
interpolation.

(10) If a previously tested filter is modified in a manner that could
change the removal efficiency of the filter product line, challenge
testing to demonstrate the removal efficiency of the modified filter
must be conducted and submitted to the State.

(b) Membrane filtration. (1) Systems receive Cryptosporidium treatment
credit for membrane filtration that meets the criteria of this
paragraph. Membrane cartridge filters that meet the definition of
membrane filtration in §141.2 are eligible for this credit. The level
of treatment credit a system receives is equal to the lower of the
values determined under paragraph (b)(1)(i) and (ii) of this section.

(i) The removal efficiency demonstrated during challenge testing
conducted under the conditions in paragraph (b)(2) of this section.

(ii) The maximum removal efficiency that can be verified through direct
integrity testing used with the membrane filtration process under the
conditions in paragraph (b)(3) of this section.

(2) Challenge testing. The membrane used by the system must undergo
challenge testing to evaluate removal efficiency, and the system must
report the results of challenge testing to the State. Challenge testing
must be conducted according to the criteria in paragraphs (b)(2)(i)
through (vii) of this section. Systems may use data from challenge
testing conducted prior to January 5, 2006 if the prior testing was
consistent with the criteria in paragraphs (b)(2)(i) through (vii) of
this section.

(i) Challenge testing must be conducted on either a full-scale membrane
module, identical in material and construction to the membrane modules
used in the system's treatment facility, or a smaller-scale membrane
module, identical in material and similar in construction to the
full-scale module. A module is defined as the smallest component of a
membrane unit in which a specific membrane surface area is housed in a
device with a filtrate outlet structure.

(ii) Challenge testing must be conducted using Cryptosporidium oocysts
or a surrogate that is removed no more efficiently than Cryptosporidium
oocysts. The organism or surrogate used during challenge testing is
referred to as the challenge particulate. The concentration of the
challenge particulate, in both the feed and filtrate water, must be
determined using a method capable of discretely quantifying the specific
challenge particulate used in the test; gross measurements such as
turbidity may not be used.

(iii) The maximum feed water concentration that can be used during a
challenge test is based on the detection limit of the challenge
particulate in the filtrate and must be determined according to the
following equation:

Maximum Feed Concentration = 3.16 × 106 × (Filtrate Detection Limit)

(iv) Challenge testing must be conducted under representative hydraulic
conditions at the maximum design flux and maximum design process
recovery specified by the manufacturer for the membrane module. Flux is
defined as the throughput of a pressure driven membrane process
expressed as flow per unit of membrane area. Recovery is defined as the
volumetric percent of feed water that is converted to filtrate over the
course of an operating cycle uninterrupted by events such as chemical
cleaning or a solids removal process ( i.e. , backwashing).

(v) Removal efficiency of a membrane module must be calculated from the
challenge test results and expressed as a log removal value according to
the following equation:

LRV = LOG10(Cf) − LOG10(Cp)

Where:

LRV = log removal value demonstrated during the challenge test; Cf= the
feed concentration measured during the challenge test; and Cp= the
filtrate concentration measured during the challenge test. Equivalent
units must be used for the feed and filtrate concentrations. If the
challenge particulate is not detected in the filtrate, the term Cpis set
equal to the detection limit for the purpose of calculating the LRV. An
LRV must be calculated for each membrane module evaluated during the
challenge test.

(vi) The removal efficiency of a membrane filtration process
demonstrated during challenge testing must be expressed as a log removal
value (LRVC-Test). If fewer than 20 modules are tested, then LRVC-Testis
equal to the lowest of the representative LRVs among the modules tested.
If 20 or more modules are tested, then LRVC-Testis equal to the 10th
percentile of the representative LRVs among the modules tested. The
percentile is defined by (i/(n+1)) where i is the rank of n individual
data points ordered lowest to highest. If necessary, the 10th percentile
may be calculated using linear interpolation.

(vii) The challenge test must establish a quality control release value
(QCRV) for a non-destructive performance test that demonstrates the
Cryptosporidium removal capability of the membrane filtration module.
This performance test must be applied to each production membrane module
used by the system that was not directly challenge tested in order to
verify Cryptosporidium removal capability. Production modules that do
not meet the established QCRV are not eligible for the treatment credit
demonstrated during the challenge test.

(viii) If a previously tested membrane is modified in a manner that
could change the removal efficiency of the membrane or the applicability
of the non-destructive performance test and associated QCRV, additional
challenge testing to demonstrate the removal efficiency of, and
determine a new QCRV for, the modified membrane must be conducted and
submitted to the State.

(3) Direct integrity testing. Systems must conduct direct integrity
testing in a manner that demonstrates a removal efficiency equal to or
greater than the removal credit awarded to the membrane filtration
process and meets the requirements described in paragraphs (b)(3)(i)
through (vi) of this section. A direct integrity test is defined as a
physical test applied to a membrane unit in order to identify and
isolate integrity breaches ( i.e. , one or more leaks that could result
in contamination of the filtrate).

(i) The direct integrity test must be independently applied to each
membrane unit in service. A membrane unit is defined as a group of
membrane modules that share common valving that allows the unit to be
isolated from the rest of the system for the purpose of integrity
testing or other maintenance.

(ii) The direct integrity method must have a resolution of 3 micrometers
or less, where resolution is defined as the size of the smallest
integrity breach that contributes to a response from the direct
integrity test.

(iii) The direct integrity test must have a sensitivity sufficient to
verify the log treatment credit awarded to the membrane filtration
process by the State, where sensitivity is defined as the maximum log
removal value that can be reliably verified by a direct integrity test.
Sensitivity must be determined using the approach in either paragraph
(b)(3)(iii)(A) or (B) of this section as applicable to the type of
direct integrity test the system uses.

(A) For direct integrity tests that use an applied pressure or vacuum,
the direct integrity test sensitivity must be calculated according to
the following equation:

LRVDIT= LOG10(Qp/(VCF × Qbreach))

Where:

LRVDIT= the sensitivity of the direct integrity test; Qp= total design
filtrate flow from the membrane unit; Qbreach= flow of water from an
integrity breach associated with the smallest integrity test response
that can be reliably measured, and VCF = volumetric concentration
factor. The volumetric concentration factor is the ratio of the
suspended solids concentration on the high pressure side of the membrane
relative to that in the feed water.

(B) For direct integrity tests that use a particulate or molecular
marker, the direct integrity test sensitivity must be calculated
according to the following equation:

LRVDIT= LOG10(Cf)−LOG10(Cp)

Where:

LRVDIT= the sensitivity of the direct integrity test; Cf= the typical
feed concentration of the marker used in the test; and Cp= the filtrate
concentration of the marker from an integral membrane unit.

(iv) Systems must establish a control limit within the sensitivity
limits of the direct integrity test that is indicative of an integral
membrane unit capable of meeting the removal credit awarded by the
State.

(v) If the result of a direct integrity test exceeds the control limit
established under paragraph (b)(3)(iv) of this section, the system must
remove the membrane unit from service. Systems must conduct a direct
integrity test to verify any repairs, and may return the membrane unit
to service only if the direct integrity test is within the established
control limit.

(vi) Systems must conduct direct integrity testing on each membrane unit
at a frequency of not less than once each day that the membrane unit is
in operation. The State may approve less frequent testing, based on
demonstrated process reliability, the use of multiple barriers effective
for Cryptosporidium , or reliable process safeguards.

(4) Indirect integrity monitoring. Systems must conduct continuous
indirect integrity monitoring on each membrane unit according to the
criteria in paragraphs (b)(4)(i) through (v) of this section. Indirect
integrity monitoring is defined as monitoring some aspect of filtrate
water quality that is indicative of the removal of particulate matter. A
system that implements continuous direct integrity testing of membrane
units in accordance with the criteria in paragraphs (b)(3)(i) through
(v) of this section is not subject to the requirements for continuous
indirect integrity monitoring. Systems must submit a monthly report to
the State summarizing all continuous indirect integrity monitoring
results triggering direct integrity testing and the corrective action
that was taken in each case.

(i) Unless the State approves an alternative parameter, continuous
indirect integrity monitoring must include continuous filtrate turbidity
monitoring.

(ii) Continuous monitoring must be conducted at a frequency of no less
than once every 15 minutes.

(iii) Continuous monitoring must be separately conducted on each
membrane unit.

(iv) If indirect integrity monitoring includes turbidity and if the
filtrate turbidity readings are above 0.15 NTU for a period greater than
15 minutes (i.e., two consecutive 15-minute readings above 0.15 NTU),
direct integrity testing must immediately be performed on the associated
membrane unit as specified in paragraphs (b)(3)(i) through (v) of this
section.

(v) If indirect integrity monitoring includes a State-approved
alternative parameter and if the alternative parameter exceeds a
State-approved control limit for a period greater than 15 minutes,
direct integrity testing must immediately be performed on the associated
membrane units as specified in paragraphs (b)(3)(i) through (v) of this
section.

(c) Second stage filtration. Systems receive 0.5-log Cryptosporidium
treatment credit for a separate second stage of filtration that consists
of sand, dual media, GAC, or other fine grain media following granular
media filtration if the State approves. To be eligible for this credit,
the first stage of filtration must be preceded by a coagulation step and
both filtration stages must treat the entire plant flow taken from a
surface water or GWUDI source. A cap, such as GAC, on a single stage of
filtration is not eligible for this credit. The State must approve the
treatment credit based on an assessment of the design characteristics of
the filtration process.

(d) Slow sand filtration (as secondary filter). Systems are eligible to
receive 2.5-log Cryptosporidium treatment credit for a slow sand
filtration process that follows a separate stage of filtration if both
filtration stages treat entire plant flow taken from a surface water or
GWUDI source and no disinfectant residual is present in the influent
water to the slow sand filtration process. The State must approve the
treatment credit based on an assessment of the design characteristics of
the filtration process. This paragraph does not apply to treatment
credit awarded to slow sand filtration used as a primary filtration
process.

[71 FR 769, Jan. 5, 2006; 71 FR 6136, Feb. 6, 2006]

§ 141.720   Inactivation toolbox components.

(a) Calculation of CT values. (1) CT is the product of the disinfectant
contact time (T, in minutes) and disinfectant concentration (C, in
milligrams per liter). Systems with treatment credit for chlorine
dioxide or ozone under paragraph (b) or (c) of this section must
calculate CT at least once each day, with both C and T measured during
peak hourly flow as specified in §§141.74(a) through (b).

(2) Systems with several disinfection segments in sequence may calculate
CT for each segment, where a disinfection segment is defined as a
treatment unit process with a measurable disinfectant residual level and
a liquid volume. Under this approach, systems must add the
Cryptosporidium CT values in each segment to determine the total CT for
the treatment plant.

(b) CT values for chlorine dioxide and ozone. (1) Systems receive the
Cryptosporidium treatment credit listed in this table by meeting the
corresponding chlorine dioxide CT value for the applicable water
temperature, as described in paragraph (a) of this section.

CT Values (mg·min/L) for Cryptosporidium Inactivation by Chlorine
Dioxide1

Log credit

Water Temperature, °C

<=0.5

1

2

3

5

7

10

15

20

25

30

(i) 0.25

159

153

140

128

107

90

69

45

29

19

12

(ii) 0.5

319

305

279

256

214

180

138

89

58

38

24

(iii) 1.0

637

610

558

511

429

360

277

179

116

75

49

(iv) 1.5

956

915

838

767

643

539

415

268

174

113

73

(v) 2.0

1275

1220

1117

1023

858

719

553

357

232

150

98

(vi) 2.5

1594

1525

1396

1278

1072

899

691

447

289

188

122

(vii) 3.0

1912

1830

1675

1534

1286

1079

830

536

347

226

147

1Systems may use this equation to determine log credit between the
indicated values: Log credit = (0.001506 × (1.09116)Temp) × CT.

(2) Systems receive the Cryptosporidium treatment credit listed in this
table by meeting the corresponding ozone CT values for the applicable
water temperature, as described in paragraph (a) of this section.

CT Values (mg·min/L) for Cryptosporidium Inactivation by Ozone1

Log credit

Water Temperature, °C

<=0.5

1

2

3

5

7

10

15

20

25

30

(i) 0.25

6.0

5.8

5.2

4.8

4.0

3.3

2.5

1.6

1.0

0.6

0.39

(ii) 0.5

12

12

10

9.5

7.9

6.5

4.9

3.1

2.0

1.2

0.78

(iii) 1.0

24

23

21

19

16

13

9.9

6.2

3.9

2.5

1.6

(iv) 1.5

36

35

31

29

24

20

15

9.3

5.9

3.7

2.4

(v) 2.0

48

46

42

38

32

26

20

12

7.8

4.9

3.1

(vi) 2.5

60

58

52

48

40

33

25

16

9.8

6.2

3.9

(vii) 3.0

72

69

63

57

47

39

30

19

12

7.4

4.7

1Systems may use this equation to determine log credit between the
indicated values: Log credit = (0.0397 × (1.09757)Temp) × CT.

(c) Site-specific study. The State may approve alternative chlorine
dioxide or ozone CT values to those listed in paragraph (b) of this
section on a site-specific basis. The State must base this approval on a
site-specific study a system conducts that follows a State-approved
protocol.

(d) Ultraviolet light. Systems receive Cryptosporidium, Giardia lamblia,
and virus treatment credits for ultraviolet (UV) light reactors by
achieving the corresponding UV dose values shown in paragraph (d)(1) of
this section. Systems must validate and monitor UV reactors as described
in paragraphs (d)(2) and (3) of this section to demonstrate that they
are achieving a particular UV dose value for treatment credit.

(1) UV dose table. The treatment credits listed in this table are for UV
light at a wavelength of 254 nm as produced by a low pressure mercury
vapor lamp. To receive treatment credit for other lamp types, systems
must demonstrate an equivalent germicidal dose through reactor
validation testing, as described in paragraph (d)(2) of this section.
The UV dose values in this table are applicable only to post-filter
applications of UV in filtered systems and to unfiltered systems.

UV Dose Table for Cryptosporidium, Giardia lamblia, and Virus
Inactivation Credit

Log credit

Cryptosporidium 

UV dose (mJ/cm2)

Giardia lamblia 

UV dose (mJ/cm2)

Virus

UV dose (mJ/cm2)

(i) 0.5

1.6

1.5

39

(ii) 1.0

2.5

2.1

58

(iii) 1.5

3.9

3.0

79

(iv) 2.0

5.8

5.2

100

(v) 2.5

8.5

7.7

121

(vi) 3.0

12

11

143

(vii) 3.5

15

15

163

(viii) 4.0

22

22

186

(2) Reactor validation testing. Systems must use UV reactors that have
undergone validation testing to determine the operating conditions under
which the reactor delivers the UV dose required in paragraph (d)(1) of
this section ( i.e. , validated operating conditions). These operating
conditions must include flow rate, UV intensity as measured by a UV
sensor, and UV lamp status.

(i) When determining validated operating conditions, systems must
account for the following factors: UV absorbance of the water; lamp
fouling and aging; measurement uncertainty of on-line sensors; UV dose
distributions arising from the velocity profiles through the reactor;
failure of UV lamps or other critical system components; and inlet and
outlet piping or channel configurations of the UV reactor.

(ii) Validation testing must include the following: Full scale testing
of a reactor that conforms uniformly to the UV reactors used by the
system and inactivation of a test microorganism whose dose response
characteristics have been quantified with a low pressure mercury vapor
lamp.

(iii) The State may approve an alternative approach to validation
testing.

(3) Reactor monitoring. (i) Systems must monitor their UV reactors to
determine if the reactors are operating within validated conditions, as
determined under paragraph (d)(2) of this section. This monitoring must
include UV intensity as measured by a UV sensor, flow rate, lamp status,
and other parameters the State designates based on UV reactor operation.
Systems must verify the calibration of UV sensors and must recalibrate
sensors in accordance with a protocol the State approves.

(ii) To receive treatment credit for UV light, systems must treat at
least 95 percent of the water delivered to the public during each month
by UV reactors operating within validated conditions for the required UV
dose, as described in paragraphs (d)(1) and (2) of this section. Systems
must demonstrate compliance with this condition by the monitoring
required under paragraph (d)(3)(i) of this section.

Reporting and Recordkeeping Requirements

§ 141.721   Reporting requirements.

(a) Systems must report sampling schedules under §141.702 and source
water monitoring results under §141.706 unless they notify the State
that they will not conduct source water monitoring due to meeting the
criteria of §141.701(d).

(b) Systems must report the use of uncovered finished water storage
facilities to the State as described in §141.714.

(c) Filtered systems must report their Cryptosporidium bin
classification as described in §141.710.

(d) Unfiltered systems must report their mean source water
Cryptosporidium level as described in §141.712.

(e) Systems must report disinfection profiles and benchmarks to the
State as described in §§141.708 through 141.709 prior to making a
significant change in disinfection practice.

(f) Systems must report to the State in accordance with the following
table for any microbial toolbox options used to comply with treatment
requirements under §141.711 or §141.712. Alternatively, the State may
approve a system to certify operation within required parameters for
treatment credit rather than reporting monthly operational data for
toolbox options.

Microbial Toolbox Reporting Requirements

Toolbox option

Systems must submit the following information

On the following schedule

(1) Watershed control program (WCP)

(i) Notice of intention to develop a new or continue an existing
watershed control program

No later than two years before the applicable treatment compliance date
in §141.713

  

(ii) Watershed control plan

No later than one year before the applicable treatment compliance date
in §141.713.

  

(iii) Annual watershed control program status report

Every 12 months, beginning one year after the applicable treatment
compliance date in §141.713.

  

(iv) Watershed sanitary survey report

For community water systems, every three years beginning three years
after the applicable treatment compliance date in §141.713. For
noncommunity water systems, every five years beginning five years after
the applicable treatment compliance date in §141.713.

(2) Alternative source/intake management

Verification that system has relocated the intake or adopted the intake
withdrawal procedure reflected in monitoring results

No later than the applicable treatment compliance date in §141.713.

(3) Presedimentation

Monthly verification of the following: (i) Continuous basin operation
(ii) Treatment of 100% of the flow (iii) Continuous addition of a
coagulant (iv) At least 0.5-log mean reduction of influent turbidity or
compliance with alternative State-approved performance criteria

Monthly reporting within 10 days following the month in which the
monitoring was conducted, beginning on the applicable treatment
compliance date in §141.713.

(4) Two-stage lime softening

Monthly verification of the following: (i) Chemical addition and
hardness precipitation occurred in two separate and sequential softening
stages prior to filtration (ii) Both stages treated 100% of the plant
flow

Monthly reporting within 10 days following the month in which the
monitoring was conducted, beginning on the applicable treatment
compliance date in §141.713.

(5) Bank filtration

(i) Initial demonstration of the following: (A) Unconsolidated,
predominantly sandy aquifer (B) Setback distance of at least 25 ft.
(0.5-log credit) or 50 ft. (1.0-log credit)

No later than the applicable treatment compliance date in §141.713.

  

(ii) If monthly average of daily max turbidity is greater than 1 NTU
then system must report result and submit an assessment of the cause.

Report within 30 days following the month in which the monitoring was
conducted, beginning on the applicable treatment compliance date in
§141.713.

(6) Combined filter performance

Monthly verification of combined filter effluent (CFE) turbidity levels
less than or equal to 0.15 NTU in at least 95 percent of the 4 hour CFE
measurements taken each month

Monthly reporting within 10 days following the month in which the
monitoring was conducted, beginning on the applicable treatment
compliance date in §141.713.

(7) Individual filter performance

Monthly verification of the following: (i) Individual filter effluent
(IFE ) turbidity levels less than or equal to 0.15 NTU in at least 95
percent of samples each month in each filter (ii) No individual filter
greater than 0.3 NTU in two consecutive readings 15 minutes apart

Monthly reporting within 10 days following the month in which the
monitoring was conducted, beginning on the applicable treatment
compliance date in §141.713.]

(8) Demonstration of performance

(i) Results from testing following a State approved protocol

(ii) As required by the State, monthly verification of operation within
conditions of State approval for demonstration of performance credit

No later than the applicable treatment compliance date in §141.713.

Within 10 days following the month in which monitoring was conducted,
beginning on the applicable treatment compliance date in §141.713.

(9) Bag filters and cartridge filters

(i) Demonstration that the following criteria are met: (A) Process meets
the definition of bag or cartridge filtration; (B) Removal efficiency
established through challenge testing that meets criteria in this
subpart

No later than the applicable treatment compliance date in §141.713.

  

(ii) Monthly verification that 100% of plant flow was filtered

Within 10 days following the month in which monitoring was conducted,
beginning on the applicable treatment compliance date in §141.713.

(10) Membrane filtration

(i) Results of verification testing demonstrating the following: (A)
Removal efficiency established through challenge testing that meets
criteria in this subpart; (B) Integrity test method and parameters,
including resolution, sensitivity, test frequency, control limits, and
associated baseline

No later than the applicable treatment compliance date in §141.713.

  

(ii) Monthly report summarizing the following: (A) All direct integrity
tests above the control limit; (B) If applicable, any turbidity or
alternative state-approved indirect integrity monitoring results
triggering direct integrity testing and the corrective action that was
taken

Within 10 days following the month in which monitoring was conducted,
beginning on the applicable treatment compliance date in §141.713.

(11) Second stage filtration

Monthly verification that 100% of flow was filtered through both stages
and that first stage was preceded by coagulation step

Within 10 days following the month in which monitoring was conducted,
beginning on the applicable treatment compliance date in §141.713.

(12) Slow sand filtration (as secondary filter)

Monthly verification that both a slow sand filter and a preceding
separate stage of filtration treated 100% of flow from subpart H
sources.

Within 10 days following the month in which monitoring was conducted,
beginning on the applicable treatment compliance date in §141.713.

(13) Chlorine dioxide

Summary of CT values for each day as described in §141.720.

Within 10 days following the month in which monitoring was conducted,
beginning on the applicable treatment compliance date in §141.713.

(14) Ozone

Summary of CT values for each day as described in §141.720.

Within 10 days following the month in which monitoring was conducted,
beginning on the applicable treatment compliance date in §141.713.

(15) UV

(i) Validation test results demonstrating operating conditions that
achieve required UV dose

(ii) Monthly report summarizing the percentage of water entering the
distribution system that was not treated by UV reactors operating within
validated conditions for the required dose as specified in 141.720(d).

No later than the applicable treatment compliance date in §141.713.

Within 10 days following the month in which monitoring was conducted,
beginning on the applicable treatment compliance date in §141.713.

§ 141.722   Recordkeeping requirements.

(a) Systems must keep results from the initial round of source water
monitoring under §141.701(a) and the second round of source water
monitoring under §141.701(b) until 3 years after bin classification
under §141.710 for filtered systems or determination of the mean
Cryptosporidium level under §141.710 for unfiltered systems
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(c) Systems must keep the results of treatment monitoring associated
with microbial toolbox options under §§141.716 through 141.720 and
with uncovered finished water reservoirs under §141.714, as applicable,
for 3 years.

Requirements for Sanitary Surveys Performed by EPA

§ 141.723   Requirements to respond to significant deficiencies
identified in sanitary surveys performed by EPA.

(a) A sanitary survey is an onsite review of the water source
(identifying sources of contamination by using results of source water
assessments where available), facilities, equipment, operation,
maintenance, and monitoring compliance of a PWS to evaluate the adequacy
of the PWS, its sources and operations, and the distribution of safe
drinking water.

(b) For the purposes of this section, a significant deficiency includes
a defect in design, operation, or maintenance, or a failure or
malfunction of the sources, treatment, storage, or distribution system
that EPA determines to be causing, or has the potential for causing the
introduction of contamination into the water delivered to consumers.

(c) For sanitary surveys performed by EPA, systems must respond in
writing to significant deficiencies identified in sanitary survey
reports no later than 45 days after receipt of the report, indicating
how and on what schedule the system will address significant
deficiencies noted in the survey.

(d) Systems must correct significant deficiencies identified in sanitary
survey reports according to the schedule approved by EPA, or if there is
no approved schedule, according to the schedule reported under paragraph
(c) of this section if such deficiencies are within the control of the
system.

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