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e-CFR data is current as of September 24, 2020

Title 40Chapter ISubchapter DPart 141Subpart W → Subject Group


Title 40: Protection of Environment
PART 141—NATIONAL PRIMARY DRINKING WATER REGULATIONS
Subpart W—Enhanced Treatment for Cryptosporidium


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 §141.701Cryptosporidium <0.075 oocyst/LBin 1.
      0.075 oocysts/L ≤Cryptosporidium <1.0 oocysts/LBin 2.
      1.0 oocysts/L ≤Cryptosporidium <3.0 oocysts/LBin 3.
      Cryptosporidium ≥3.0 oocysts/LBin 4.
.  .  . serving fewer than 10,000 people and NOT required to monitor for Cryptosporidium under §141.701(a)(4)NABin 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 1No additional treatmentNo additional treatmentNo additional treatmentNo additional treatment.
Bin 21-log treatment1.5-log treatment1-log treatment(1)
Bin 32-log treatment2.5-log treatment2-log treatment(2)
Bin 42.5-log treatment3-log treatment2.5-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.

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