(1) General Requirements.

1. (a) 310 CMR 22.20F establishes requirements for filtration and disinfection that are in addition to criteria under 310 CMR 22.20A. The requirements of 310 CMR 22.20F apply to public water systems serving fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water, beginning January 1, 2005 unless otherwise specified. 310 CMR 22.20F establishes or extends treatment technique requirements in lieu of maximum contaminant levels for the following contaminants:

   1. 1. Giardia lamblia;
   2. 2. Viruses;
   3. 3. Heterotrophic plate count bacteria;
   4. 4. Legionella;
   5. 5. Cryptosporidium; and
   6. 6. Turbidity.

2. (b) Each supplier of water serving fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water shall provide treatment of its source water that complies with the treatment technique requirements set forth in 310 CMR 22.20F in addition to the requirements identified in 310 CMR 22.20A. The treatment technique requirements set out in 310 CMR 22.20F consist of installing and properly operating water treatment processes that reliably achieve:

   1. 1. At least 99% (2-log) removal of Cryptosporidium between a point where water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer for filtered systems, or Cryptosporidium control under the watershed control plan for unfiltered systems.
   2. 2. Compliance with the profiling and benchmark requirements in 310 CMR 22.20F(4)(a) through (5)(e).

3. (c) A public water system subject to the requirements of 310 CMR 22.20F shall also meet the following requirements:

   1. 1. It shall cover any finished water reservoir that started construction on or after March 15, 2002 as described in 310 CMR 22.20F(2)(a) and (b).
   2. 2. If it is an unfiltered system, it shall comply with the updated watershed control requirements described in 310 CMR 22.20F(3)(a) through (c).
   3. 3. If it is a community or non-transient non-community water systems, it shall develop a disinfection profile as described in 310 CMR 22.20F(4)(a) through (g).
   4. 4. If it is considering making a significant change to its disinfection practices, it shall develop a disinfection benchmark and consult with the Department for approval of the change as described in 310 CMR 22.20F(5)(a) through (e).
   5. 5. If it is a filtered system, it shall comply with the combined filter effluent requirements as described in 310 CMR 22.20F(6)(a) through (d).
   6. 6. If it is a filtered system that uses conventional or direct filtration, it shall comply with the individual filter turbidity requirements as described in 310 CMR 22.20F(7)(a) through (e).
   7. 7. It shall comply with the applicable reporting and record keeping requirements as described in 310 CMR 22.20F(8)(a) and (b).

(2) Finished Water Reservoirs.

1. (a) Each supplier of water serving fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water is subject to 310 CMR 22.20F(2)(b).
2. (b) If the supplier of water begins construction of a finished water reservoir on or after March 15, 2002 the reservoir shall be covered. Finished water reservoirs for which the supplier of water began construction prior to March 15, 2002 are not subject to 310 CMR 22.20F(2), but are subject to 310 CMR 22.20A.

(3) Additional Watershed Control Requirements for Unfiltered Systems.

1. (a) Each supplier of water serving fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water which does not provide filtration shall continue to comply with all of the filtration avoidance criteria in 310 CMR 22.20A(2), as well as the additional watershed control requirements in 310 CMR 22.20F(3)(b).

2. (b) The supplier of water must take any additional steps necessary to minimize the potential for contamination by Cryptosporidium oocysts in the source water. The supplier of water’s watershed control program shall, for Cryptosporidium:

   1. 1. Identify watershed characteristics and activities which may have an adverse effect on source water quality; and
   2. 2. Monitor the occurrence of activities, which may have an adverse effect on source water quality.
3. (c) During an onsite inspection conducted under the provisions of 310 CMR 22.20A(2)(b)5., the Department will determine whether the watershed control program is adequate to limit potential contamination by Cryptosporidium oocysts. The adequacy of the program will be based on the comprehensiveness of the watershed review; the effectiveness of the program to monitor and control detrimental activities occurring in the watershed; and the extent to which the supplier of water has maximized land ownership and/or controlled land use within the watershed.

(4) Disinfection Profiling.

1. (a) Each supplier of water, community or non-transient non-community water system, serving fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water shall develop a disinfection profile unless the Department determines that the system’s profile is unnecessary. The Department may approve the use of a more representative data set for disinfection profiling than the data set required in 310 CMR 22.20F(4)(c) through (g).
2. (b) The Department may only determine that a system’s profile is unnecessary if a system’s TTHM and HAA5 levels are below 0.064 mg/L and 0.048 mg/L, respectively. To determine these levels, TTHM and HAA5 samples must be collected after January 1, 1998, during the month with the warmest water temperature, and at the point of maximum residence time in the distribution system.

3. (c) A disinfection profile shall be developed using the following three steps:

   1. 1. The supplier of water shall collect data for several parameters from the plant as required in 310 CMR 22.20F(4)(d) over the course of 12 months. If the system serves between 500 and 9,999 persons the supplier of water must begin to collect data no later than July 1, 2003. If the system serves fewer than 500 persons the supplier of water must begin to collect data no later than January 1, 2004;
   2. 2. The supplier of water shall use the data to calculate weekly log inactivation as required in 310 CMR 22.20F(4)(e) and (f); and
   3. 3. The supplier of water shall use these weekly log inactivations to develop a disinfection profile as specified in 310 CMR 22.20F(4)(g).

4. (d) The supplier of water shall monitor the following parameters to determine the total log inactivation using the analytical methods in 310 CMR 22.20A(5)(a), once per week on the same calendar day, over 12 consecutive months:

   1. 1. The temperature of the disinfected water at each residual disinfectant concentration sampling point during peak hourly flow;
   2. 2. If the system uses chlorine, the pH of the disinfected water at each residual disinfectant concentration sampling point during peak hourly flow;
   3. 3. The disinfectant contact time(s) (“T”) during peak hourly flow; and
   4. 4. The residual disinfectant concentration(s) (“C”) of the water before or at the first customer and prior to each additional point of disinfection during peak hourly flow.

5. (e) Use the tables in 310 CMR 22.20A(5)(b)3.e. to determine the appropriate CT value. 99.9 The supplier of water shall calculate the total inactivation ratio as follows, and multiply the value by 3.0 to determine the log inactivation of Giardia lamblia:

   1. 1. If the supplier of water uses only one point of disinfectant application, the supplier of water shall determine the total inactivation ratio for the disinfection segment based on either of the following methods:

      1. a. Determine one inactivation ratio (CTcalc/CT ) before or at the first customer 99.9 during peak hourly flow; or
      2. b. Determine successive CTcalc/CT values, representing sequential inactivation 99.9 ratios, between the point of disinfectant application and a point before or at the first customer during peak hourly flow. Under this alternative, the system must calculate the total inactivation ratio by determining (CTcalc/CT ) for each sequence and then 99.9 add the (CTcalc/CT ) values together to determine (3CTcalc/CT ). 99.9 99.9
   2. 2. If the supplier of water uses more than one point of disinfectant application before the first customer, the supplier of water shall determine the (CTcalc/CT ) value of each 99.9 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 using the procedure specified in 310 CMR 22.20F(4)(e)1.b.
6. (f) If the supplier of water uses chloramines, ozone, or chlorine dioxide for primary disinfection, the supplier of water shall also calculate the logs of inactivation for Viruses and develop an additional disinfection profile for Viruses using methods approved by the Department.
7. (g) Each supplier of water will use each log inactivation as a data point in the disinfection profile. The supplier of water will have obtained 52 measurements (one for every week of the year). This will allow the supplier of water and the Department the opportunity to evaluate how microbial inactivation varied over the course of the year by looking at all 52 measurements (the Disinfection Profile). The supplier of water shall retain the Disinfection Profile data in graphic form, such as a spreadsheet, which must be available for review by the Department as part of a sanitary survey. The supplier of water shall use this data to calculate a benchmark if they are considering changes to disinfection practices.

(5) Disinfection Benchmark.

1. (a) A supplier of water serving fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water required to develop a disinfection profile under 310 CMR 22.20F(4), shall develop a Disinfection Benchmark if the supplier of water decides to make a significant change to the disinfection practice. The supplier of water shall consult with the Department for approval before implementing a significant disinfection practice change.

2. (b) Significant changes to disinfection practice include:

   1. 1. Changes to the point of disinfection;
   2. 2. Changes to the disinfectant(s) used in the treatment plant;
   3. 3. Changes to the disinfection process; or
   4. 4. Any other modification identified by the Department.

3. (c) If the supplier of water is considering a significant change to its disinfection practice, the supplier of water shall calculate a disinfection benchmark(s) as described in 310 CMR 22.20F(5)(d) and (e) and provide the benchmark(s) to the Department. The supplier of water may only make a significant disinfection practice change after consulting with and obtaining the approval of the Department. The system shall submit the following information to the Department as part of the consultation and approval process:

   1. 1. A description of the proposed change,
   2. 2. The disinfection profile for Giardia lamblia (and, if necessary, Viruses) and disinfection benchmark,
   3. 3. An analysis of how the proposed change will affect the current levels of disinfection, and
   4. 4. Any additional information requested by the Department.

4. (d) If the supplier of water is making a significant change to its disinfection practice, the supplier of water shall calculate a disinfection benchmark using the following procedure:

   1. 1. Using the data the supplier of water collected to develop the Disinfection Profile, determine the average Giardia lamblia inactivation for each calendar month by dividing the sum of all Giardia lamblia inactivations for that month by the number of values calculated for that month.
   2. 2. Determine the lowest monthly average value out of the twelve values. This value becomes the disinfection benchmark.
5. (e) If the supplier of water uses chloramines, ozone or chlorine dioxide for primary disinfection, the supplier of water shall calculate the disinfection benchmark from the data the system collected for Viruses to develop the disinfection profile in addition to the Giardia lamblia disinfection benchmark calculated under 310 CMR 22.20F(5)(d). This viral benchmark shall be calculated in the same manner used to calculate the Giardia lamblia disinfection benchmark in 310 CMR 22.20F(5)(d).

(6) Combined Filter Effluent Requirements.

1. (a) Each supplier of water that serves fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water is required to filter, and each supplier of water that utilizes filtration other than slow sand filtration or diatomaceous earth filtration shall meet the combined filter effluent (CFE) turbidity requirements of 310 CMR 22.20F(6)(b) through (d). If the supplier of water uses slow sand or diatomaceous earth filtration the supplier of water is not required to meet the CFE turbidity limits of 310 CMR 22.20F, but such supplier of water shall continue to meet the CFE turbidity limits in 310 CMR 22.20A(4).

2. (b) Each supplier of water that serves fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water is required to filter, and each supplier of water that utilizes filtration other than slow sand filtration or diatomaceous earth filtration shall meet two strengthened CFE turbidity limits as follows:

   th

   1. 1. The first CFE turbidity limit is a “95 percentile” turbidity limit that the system shall meet in at least 95% of the turbidity measurements taken each month. Measurements must continue to be taken as described in 310 CMR 22.20A(5)(b)1. and 3. Monthly reporting shall be completed according to 310 CMR 22.20F(8).

      1. a. If the supplier of water uses conventional filtration or direct filtration, the turbidity level of representative samples of a system's filtered water shall be less than or equal to 0.3 NTU in at least 95% of the measurements taken each month, measured as specified in 310 CMR 22.20A(5)(a) and (c).
      2. b. If the supplier of water uses “alternative filtration” the turbidity level of representative samples of the system's filtered water shall be less than or equal to 0.3 NTU in at least 95% of the measurements taken each month, measured as specified in 310 CMR 22.20A(5)(a) and (c).

   2. 2. The second CFE turbidity limit is a “maximum” turbidity limit that the system may not exceed at any time during the month. Measurements shall continue to be taken as described in 310 CMR 22.20A(5)(b)1. and 3. Monthly reporting shall be completed according to 310 CMR 22.20F(8)(a). The following is a description of the required limits for specific filtration technologies:

      1. a. If the supplier of water uses conventional filtration or direct filtration, the “maximum” turbidity level is one NTU.
      2. b. If the supplier of water uses “alternative filtration” the “maximum” turbidity level is one NTU.

3. (c) Each supplier of water that serves fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water that uses a system that consists of alternative filtration (filtration other than slow sand filtration, diatomaceous earth filtration, conventional filtration, or direct filtration) is required to conduct a demonstration. The supplier of water shall demonstrate to the Department, using pilot plant studies or other means, that the system’s filtration, in combination with disinfection treatment, consistently achieves:

   1. 1. 99% removal of Cryptosporidium oocysts;
   2. 2. 99.9% removal and/or inactivation of Giardia lamblia cysts; and
   3. 3. 99.99% removal and/or inactivation of Viruses.
4. (d) Each supplier of water serving fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water that practices lime softening, may acidify representative CFE turbidity samples prior to analysis using a protocol approved by the Department.

(7) Individual Filter Turbidity Requirements.

1. (a) Each supplier of water serving fewer than 10,000 people using a surface water source or ground water source under the direct influence of surface water that utilizes conventional filtration or direct filtration, shall conduct continuous monitoring of turbidity for each individual filter at the filtration facility. The following requirements apply to continuous turbidity monitoring:

   1. 1. Monitoring must be conducted using an approved method in 310 CMR 22.20A(5)(a);
   2. 2. Calibration of turbidimeters shall be conducted using procedures specified by the manufacturer;
   3. 3. Results of turbidity monitoring shall be recorded at least every 15 minutes;
   4. 4. Monthly reporting must be completed according to 310 CMR 22.20F(8)(a); and
   5. 5. Records shall be maintained according to 310 CMR 22.20F(8)(b).
2. (b) If there is a failure in the continuous turbidity monitoring equipment, the supplier of water shall conduct grab sampling every four hours in lieu of continuous monitoring until the turbidimeter is back on-line. The system has 14 days to resume continuous monitoring before a violation is incurred.
3. (c) If the system only consists of one or two, the supplier of water may conduct continuous monitoring of the CFE turbidity in lieu of individual filter effluent turbidity monitoring. Continuous monitoring shall meet the same requirements set forth in 310 CMR 22.20F(7)(a)1. through 4. and (b).

4. (d) If the supplier of water conducts continuous turbidity monitoring, follow-up action is required as follows:

   1. 1. If the turbidity of an individual filter or the turbidity of the CFE for systems with two filters that monitor CFE in lieu of individual filters exceeds 1.0 NTU in two consecutive recordings 15 minutes apart, the supplier of water shall report to the Department by the tenth day of the following month and include the filter number(s), corresponding date(s), turbidity value(s) which exceeded 1.0 NTU, and the cause (if known) for the exceedance(s).
   2. 2. If the supplier of water was required to report to the Department for three months in a row and turbidity exceeded 1.0 NTU in two consecutive recordings 15 minutes apart at the same filter or CFE for systems with two filters that monitor CFE in lieu of individual filters, the supplier of water shall conduct a self-assessment of the filter(s) within 14 days of the day the filter exceeded 1.0 NTU in two consecutive measurements for the third straight month unless a Comprehensive Performance Evaluation (CPE) as specified in 310 CMR 22.20F(7)(d)3. was required. Systems with two filters that monitor CFE in lieu of individual filters shall conduct a self-assessment on both filters. The self-assessment must consist of at least the following components: assessment of filter performance; development of a filter profile; identification and prioritization of factors limiting filter performance; assessment of the applicability of corrections; and preparation of a filter self-assessment report. If a self-assessment is required, the date that it was triggered and the date that it was completed shall be included.
   3. 3. If the supplier of water was required to report to the Department for two months in a row and turbidity exceeded 2.0 NTU in two consecutive recordings 15 minutes apart at the same filter or CFE for systems with two filters that monitor CFE in lieu of individual filters, the supplier of water shall arrange to have a CPE conducted by the Department no later than 60 days following the day the filter exceeded 2.0 NTU in two consecutive measurements for the second straight month. If a CPE has been completed by the Department within the 12 prior months or the supplier of water and the Department are jointly participating in an ongoing Comprehensive Technical Assistance
   4. (CTA) project at the system, a new CPE is not required. If conducted, a CPE must be completed and submitted to the Department no later than 120 days following the day the filter exceeded 2.0 NTU in two consecutive measurements for the second straight month.
5. (e) If the supplier of water practices lime softening, the supplier of water may apply to the Department for alternative turbidity exceedance levels for the levels specified in 310 CMR 22.20F(7)(d). The supplier of water shall be able to demonstrate to the Department that higher turbidity levels are due to lime carryover only, and not due to degraded filter performance.

(8) Reporting and Recordkeeping.

1. (a) In addition to the reporting and recordkeeping requirements in 310 CMR 22.20A, each supplier of water who is subject to the requirements of 310 CMR 22.20F shall report the following information to the Department at the frequency specified, if the supplier of water is subject to the specific requirement.

   1. 1. Combined filter requirements that shall be reported within ten days after the end of each month shall include:

      1. a. The total number of filtered water turbidity measurements taken during the month.
      2. b. The number and percentage of filtered water turbidity measurements taken during the month which are less than or equal to the turbidity limits specified in 310 CMR 22.20F(7).
      3. c. The date and value of any turbidity measurements taken during the month which exceed 1.0 NTU for systems using conventional filtration treatment or direct filtration, or exceed the maximum level set by the Department 310 CMR 22.20F(7).

   2. 2. The individual turbidity requirements that shall be reported within ten days after the end of each month, except as otherwise provided in 310 CMR 22.20F(8)2.c. and 310 CMR 22.20F(8)2.e., shall include:

      1. a. That the supplier of water conducted individual filter turbidity monitoring during the month.
      2. b. The filter number(s), corresponding date(s), and turbidity value(s) that exceeded 1.0 NTU during the month, and the cause (if known) for the exceedance(s) but only in if two consecutive measurements exceeded 1.0 NTU.
      3. c. If a self-assessment is required, the date that it was triggered and the date that it was completed. If the self-assessment was triggered during the last four days of the month, the date that it was triggered and the date that it was completed shall be reported within 14 days after the date the self-assessment was triggered.
      4. d. If a CPE is required and the date that it was triggered.
      5. e. Copy of completed CPE report within 120 days after the CPE was triggered.

   3. 3. Disinfection Profiling shall include:

      1. a. Results of optional monitoring that show TTHM levels <0.064 mg/l and HAA5 levels <0.048 mg/l (only if the system wishes to forgo profiling) or that the system has begun disinfection profiling.

         1. i. For systems serving 500–9,999 by July 1, 2003;
         2. ii. For systems serving fewer than 500 by January 1, 2004.
   4. 4. Disinfection Benchmarking shall include: A description of the proposed change in disinfection, the system’s disinfection profile for Giardia lamblia (and, if necessary, Viruses) and disinfection benchmark, and an analysis of how the proposed change will affect the current levels of disinfection anytime a significant change in disinfection practices is being considered.
2. (b) Each supplier of water who is subject to the requirements of 310 CMR 22.20F shall, in addition to recordkeeping requirements under 310 CMR 22.20A(6), maintain records in accordance with 310 CMR 22.17(12).