S.C. Code Ann. Regs. 61-58.10
Table of Contents
A. Applicability.
(1) This regulation establishes criteria and requirements for the filtration and disinfection of drinking water served to the public. This regulation shall apply to each community and non-community water system, unless the water system meets all of the following conditions:
B. General Requirements.
(1) The requirements of this regulation constitute national primary drinking water regulations. These regulations establish criteria under which filtration is required as a treatment technique for 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. In addition, these regulations establish treatment technique requirements in lieu of maximum contaminant levels for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, and turbidity. Each public water system with a surface water source or a ground water source under the direct influence of surface water shall provide treatment of that source water that complies with these treatment technique requirements. The treatment technique requirements consist of installing and properly operating water treatment processes which reliably achieve:
(2) A public water system using a surface water source or a ground water source under the direct influence of surface water is considered to be in compliance with the requirements of paragraph (1) of this section if:
C. Criteria for Avoiding Filtration.
(1) Source water quality conditions.
(b) The turbidity level cannot exceed 5 NTU [measured as specified in R.61-58.10(F)(1)(d) and (2)(b)] in representative samples of the source water immediately prior to the first or only point of disinfectant application unless:
(2) Site-specific conditions.
(ii) The public water system shall meet the requirements of R.61-58.10(D)(1)(b) at all times the system serves water to the public.
(iii) The public water system shall meet the requirements of R.61-58.10(D)(1)(c) at all times the system serves water to the public unless the Department determines that any such failure was caused by circumstances that were unusual and unpredictable.
(b) The public water system shall maintain a watershed control program which minimizes the potential for contamination by Giardia lamblia cysts and viruses in the source water. The Department shall determine whether the watershed control program is adequate to meet this goal. The adequacy of a program to limit potential contamination by Giardia lamblia cysts and viruses shall be based on: the comprehensiveness of the watershed review; the effectiveness of the system’s program to monitor and control detrimental activities occurring in the watershed; and the extent to which the water system has maximized land ownership and/or controlled land use within the watershed. At a minimum, the watershed control program shall;
(ii) Identify watershed characteristics and activities which may have an adverse effect on source water quality; and
(iii) Monitor the occurrence of activities which may have an adverse effect on source water quality.
The public water system shall demonstrate through ownership and/or written agreements with landowners within the watershed that it can control all human activities which may have an adverse impact on the microbiological quality of the source water. The public water system shall submit an annual report to the Department that identifies any special concerns about the watershed and how they are being handled; describes activities in the watershed that affect water quality; and projects what adverse activities are expected to occur in the future and describes how the public water system expects to address them. For systems using a ground water source under the direct influence of surface water, an approved wellhead protection program developed under section 1428 of the Federal Safe Drinking Water Act may be used, if the Department deems it appropriate, to meet these requirements.
(c) The public water system shall be subject to an annual on-site inspection to assess the watershed control program and disinfection treatment process. Either the Department or a party approved by the Department shall conduct the on-site inspection. The inspection shall be conducted by competent individuals such as sanitary and civil engineers, sanitarians, or technicians who have experience and knowledge about the operation and maintenance of a public water system, and who have a sound understanding of public health principles and waterborne diseases. A report of the on-site inspection summarizing all findings shall be prepared every year. The on-site inspection shall indicate to the Department’s satisfaction that the watershed control program and disinfection treatment process are adequately designed and maintained. The on-site inspection shall include:
(ii) A review of the physical condition of the source intake and how well it is protected;
(iii) A review of the system’s equipment maintenance program to ensure there is low probability for failure of the disinfection process;
(vi) A review of data records to ensure that all required tests are being conducted and recorded and disinfection is effectively practiced; and
(vii) Identification of any improvements which are needed in the equipment, system maintenance and operation, or data collection.
(a)(i) The public water system shall meet the requirements of R.61-58.10(D)(1)(a) at least 11 of the 12 previous months that the system served water to the public, on an ongoing basis, unless the system fails to meet the requirements during 2 of the 12 previous months that the system served water to the public, and the Department determines that at least one of these failures was caused by circumstances that were unusual and unpredictable.
(3) Treatment technique violations.
(a) A system is in violation of a treatment technique requirement if:
(b) A system that has not installed filtration is in violation of a treatment technique requirement if:
A public water system that uses a surface water source shall meet all of the conditions of paragraphs (1) and (2) of this section, and is subject to paragraph (3) of this section, beginning December 30, 1991, unless the Department has determined, in writing, that filtration is required. A public water system that uses a ground water source under the direct influence of surface water shall meet all of the conditions of paragraphs (1) and (2) of this section and is subject to paragraph (3) of this section, beginning 18 months after the Department determines that it is under the direct influence of surface water, or December 30, 1991, whichever is later, unless the Department has determined, in writing, that filtration is required. If the Department determines, in writing, before December 30, 1991, that filtration is required, the system shall have installed filtration and meet the criteria for filtered systems specified in R.61-58.10(D)(2) and R.61-58.10(E) by June 29, 1993. Within 18 months of the failure of a system using surface water or a ground water source under the direct influence of surface water to meet any one of the requirements of paragraphs (1) and (2) of this section or after June 29, 1993, whichever is later, the system shall have installed filtration and meet the criteria for filtered systems specified in R.61-58.10(D)(2) and R.61-58.10(E).
D. Disinfection.
(1) Disinfection requirements for public water systems that do not provide filtration.
(b) The disinfection system shall have either:
(c) The residual disinfectant concentration in the water entering the distribution system, measured as specified in R.61-58.10(F)(1)(e) and (2)(e), cannot be less than 0.2 mg/l for more than 4 hours.
(d)(i) The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in R.61-58.10(F)(1)(e) and (2)(f), cannot be undetectable in more than 5 percent of the samples each month, for any two consecutive months that the system serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured as heterotrophic plate count (HPC) as specified in R.61-58.10(F)(1)(c), is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value “V” in the following formula cannot exceed 5 percent in one month, for any two consecutive months.
| where: | |||
| a | = | number of instances where the residual disinfectant concentration is measured; | |
| b | = | number of instances where the residual disinfectant concentration is not measured but heterotrophic bacteria plate count (HPC) is measured; | |
| c | = | number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured; | |
| d | = | number of instances where the residual disinfectant concentration is measured but not detected and where the HPC is > 500/ml; and | |
| e | = | number of instances where the residual disinfectant concentration is not measured and HPC is > 500/ml. |
Each public water system that does not provide filtration treatment shall provide disinfection treatment as follows:
(2) Disinfection requirements for public water systems which provide filtration.
(b) The residual disinfectant concentration in the water entering the distribution system, measured as specified in R.61-58.10(F)(1)(e) and (3)(b), cannot be less than 0.2 mg/l for more than 4 hours.
(c)(i) The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in R.61-58.10(F)(1)(e) and (3)(c), cannot be undetectable in more than 5 percent of the samples each month, for any two consecutive months that the system serves water to the public. Water in the distribution system with a heterotrophic bacteria concentration less than or equal to 500/ml, measured as heterotrophic plate count (HPC) as specified in R.61-58.10(F)(1)(c), is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value “V” in the following formula cannot exceed 5 percent in one month, for any two consecutive months.
| where: | |||
| a | = | number of instances where the residual disinfectant concentration is measured; | |
| b | = | number of instances where the residual disinfectant concentration is not measured but heterotrophic bacteria plate count (HPC) is measured; | |
| c | = | number of instances where the residual disinfectant concentration is measured but not detected and no HPC is measured; | |
| d | = | number of instances where no residual disinfectant concentration is detected and where the HPC is > 500/ml; and | |
| e | = | number of instances where the residual disinfectant concentration is not measured and HPC is > 500/ml. |
Each public water system that provides filtration treatment shall provide disinfection treatment as follows:
A public water system that uses a surface water source and does not provide filtration treatment shall provide the disinfection treatment specified in paragraph (1) of this section beginning December 30, 1991, unless the Department determines, in writing, that filtration is required. A public water system that uses a ground water source under the direct influence of surface water and does not provide filtration treatment shall provide disinfection treatment specified in paragraph (1) of this section beginning December 30, 1991, or 18 months after the Department determines that the ground water source is under the influence of surface water, whichever is later, unless the Department has determined, in writing, that filtration is required. If the Department has determined that filtration is required, the system shall comply with any interim disinfection requirements the Department deems necessary before filtration is installed. A system that uses a surface water source that provides filtration treatment shall provide the disinfection treatment specified in paragraph (2) of this section beginning June 29, 1993, or beginning when filtration is installed, whichever is later. A system that uses a ground water source under the direct influence of surface water and provides filtration treatment shall provide disinfection treatment as specified in paragraph (2) of this section by June 29, 1993, or beginning when filtration is installed, whichever is later. Failure to meet any requirement of this section after the applicable date specified in this introductory paragraph is a treatment technique violation.
E. Filtration.
(1) Conventional filtration treatment or direct filtration.
(2) Slow sand filtration.
(3) Diatomaceous earth filtration.
(4) Other filtration technologies.
A public water system may use a filtration technology not listed in paragraphs (1) through (3) of this section if it demonstrates to the Department, using pilot plant studies or other means, that the alternative filtration technology, in combination with disinfection treatment that meets the requirements of Section D(2), above, consistently achieves 99.9 percent removal and/or inactivation of Giardia lamblia cysts and 99.99 percent removal and/or inactivation of viruses. For a system that makes this demonstration, the requirements of paragraph (2) of this section apply. Beginning January 1, 2002, systems serving at least 10,000 people must meet the requirements for other filtration technologies in R.61-58.10.H(4)(b). Beginning January 1, 2005, systems serving fewer than 10,000 people must meet the requirements for other filtration technologies in Section I(6) below.
A public water system that uses a surface water source or a ground water source under the direct influence of surface water, and does not meet all of the criteria in R.61-58.10(C)(1) and (2) for avoiding filtration, shall provide treatment consisting of both disinfection, as specified in R.61-58.10(D)(2), and filtration treatment which complies with the requirements of paragraphs (1), (2), (3), or (4) of this section by June 29, 1993, or within 18 months of the failure to meet any one of the criteria for avoiding filtration in R.61-58.10(C)(1) and (2), whichever is later. Failure to meet any requirement of this section after the date specified in this introductory paragraph is a treatment technique violation.
F. Analytical and Monitoring Requirements.
(1) Analytical requirements.
(e) Residual disinfectant concentration—Residual disinfectant concentrations for free chlorine and combined chlorine (chloramines) shall be measured by Method 408C (Amperometric Titration Method), Method 408D (DPD Ferrous Titrimetric Method), Method 408E (DPD Colorimetric Method), or Method 408F (Leuco Crystal Violet Method), as set forth in Standard Methods for the Examination of Water and Wastewater, 1985, 16th edition. Residual disinfectant concentrations for free chlorine and combined chlorine may also be measured by using DPD colorimetric test kits if approved by the Department. Residual disinfectant concentrations for ozone must be measured by the Indigo Method as set forth in Bader, H., Hoigne, J., “Determination of Ozone in Water by the Indigo Method; A Submitted Standard Method”; Ozone Science and Engineering, Vol. 4, Pergamon Press Ltd., 1982, or automated methods which are calibrated in reference to the results obtained by the Indigo Method on a regular basis, if approved by the Department.
Residual disinfectant concentrations for chlorine dioxide shall be measured by Method 410B (Amperometric Method) or Method 410C (DPD Method), as set forth in Standard Methods for the Examination of Water and Wastewater, 1985, 16th edition.
Only the analytical method(s) specified in this paragraph, or otherwise approved by EPA, may be used to demonstrate compliance with the requirements of R.61-58.10.C, R.61-58.10.D, and R.61-58.10.E. Measurements for pH, temperature, turbidity and residual disinfectant concentrations shall be conducted by a party approved by the Department. Measurements for total coliforms, fecal coliforms, and HPC shall be conducted by a laboratory certified by the Department or EPA to do such analysis. Until laboratory certification criteria are developed for the analysis of HPC and fecal coliforms, any laboratory certified for total coliform analysis by EPA is deemed certified for HPC and fecal coliform analysis. All procedures shall be performed in accordance with EPA-approved methods outlined in 40 CFR 141 (11-8-06 edition).
(2) Monitoring requirements for systems that do not provide filtration.
(a) Fecal coliform or total coliform density measurements as required by R.61-58.10(C)(1)(a) shall be performed on representative source water samples immediately prior to the first or only point of disinfectant application. The system shall sample for fecal or total coliforms at the following minimum frequency each week the system serves water to the public:
| System size (persons served) | Samples/week1 |
| ≤500 | 1 |
| 501 to 3,300 | 2 |
| 3,301 to 10,000 | 3 |
| 10,001 to 25,000 | 4 |
| >25,000 | 5 |
| 1Must be taken on separate days. |
Also, one fecal or total coliform density measurement shall be made every day the system serves water to the public and the turbidity of the source water exceeds 1 NTU (these samples count towards the weekly coliform sampling requirements) unless the Department determines that the system, for logistical reasons outside the system’s control, cannot have the sample analyzed within 30 hours of collection.
(c) The total inactivation ratio for each day that the system is in operation shall be determined based on the CT99.9 values in Table 1.1-1.6, 2.1 and 3.1 of this section, as appropriate. The parameters necessary to determine the total inactivation ratio shall be monitored as follows:
(ii) If the system uses chlorine, the pH of the disinfected water shall be measured at least once per day at each chlorine residual disinfectant concentration sampling point.
(iii) The disinfectant contact time(s) (“T”) shall be determined for each day during peak hourly flow.
(v) If a system uses a disinfectant other than chlorine, the system may demonstrate to the Department, through the use of a Department-approved protocol for on-site disinfection challenge studies or other information satisfactory to the Department, that CT99.9 values other than those specified in Tables 2.1 and 3.1 in this section or other operational parameters are adequate to demonstrate that the system is achieving the minimum inactivation rates required by R.61-58.10(D)(1)(a).
| TABLE 3.1—CT VALUES (CT99.9) FOR 99.9 PERCENT INACTIVATION OF GIARDIA LAMBLIA CYSTS BY CHLORAMINES1 | ||||||
| Temperature | ||||||
| <1°C | 5°C | 10°C | 15°C | 20°C | 25°C | |
| 3,800 | 2,200 | 1,850 | 1,500 | 1,100 | 750 | |
| 1These values are for pH values of 6 to 9. These CT values may be assumed to achieve greater than 99.99 percent inactivation of viruses only if chlorine is added and mixed in the water prior to the addition of ammonia. If this condition is not met, the system shall demonstrate, based on on-site studies or other information, as approved by the Department, that the system is achieving at least 99.99 percent inactivation of viruses. CT values between the indicated temperatures may be determined by linear interpolation. If no interpolation is used, use the CT99.9 value at the lower temperature for determining CT99.9 values between indicated temperatures. |
A public water system that uses a surface water source and does not provide filtration treatment shall begin monitoring, as specified in this paragraph, beginning December 31, 1990, unless the Department has determined in writing that filtration is required, in which case the Department may specify alternative monitoring requirements, as appropriate, until filtration is in place. A public water system that uses a ground water source under the direct influence of surface water and does not provide filtration treatment shall begin monitoring as specified in this paragraph beginning December 31, 1990, or 6 months after the Department determines that the ground water source is under the direct influence of surface water, whichever is later, unless the Department has determined in writing that filtration is required, in which case the Department may specify alternative monitoring requirements, as appropriate, until filtration is in place.
(d) The total inactivation ratio shall be calculated as follows:
(i) If the system uses only one point of disinfectant application, the system may determine the total inactivation ratio based on either of the following two methods:
(B) Successive CTcalc/CT99.9 values, representing sequential inactivation ratios, are determined between the point of disinfectant application and a point before or at the first customer during peak hourly flow. Under this alternative, the following method shall be used to calculate the total inactivation ratio:
| Step 3: | If Σ | CTcalc | ≥ 1.0, | |
| CT99.9 |
the 99.9 percent Giardia lamblia inactivation requirement has been achieved.
(ii) If the system uses more than one point of disinfectant application before or at the first customer, the system shall determine the CT value of each disinfection sequence immediately prior to the next point of disinfectant application during peak hourly flow. The CTcalc/CT99.9 value of each sequence and
(e) The residual disinfectant concentration of the water entering the distribution system shall be monitored continuously, and the lowest value shall be recorded each day, except that if there is a failure in the continuous monitoring equipment, grab sampling every 4 hours may be conducted in lieu of continuous monitoring, but for no more than 5 working days following the failure of the equipment, and systems serving 3,300 or fewer persons may take grab samples in lieu of providing continuous monitoring on an ongoing basis at the frequencies prescribed below:
| If at any time the residual disinfectant concentration falls below 0.2 mg/l in a system using grab sampling in lieu of continuous monitoring, the system shall take a grab sample every 4 hours until the residual concentration is equal to or greater than 0.2 mg/l. |
| Σ | CTcalc | ||
| CT99.9 |
shall be calculated using the method in paragraph (2)(d)(i)(B) of this section to determine if the system is in compliance with R.61-58.10(D)(1).
(iii) Although not required, the total percent inactivation for a system with one or more points of residual disinfectant concentration monitoring may be calculated by solving the following equation:
| where z = 3 X Σ | CTcalc | ||
| CT99.9 |
(3) Monitoring requirements for systems using filtration treatment.
(b) The residual disinfectant concentration of the water entering the distribution system shall be monitored continuously, and the lowest value shall be recorded each day, except that if there is a failure in the continuous monitoring equipment, grab sampling every 4 hours may be conducted in lieu of continuous monitoring, but for no more than 5 working days following the failure of the equipment, and systems serving 3,300 or fewer persons may take grab samples in lieu of providing continuous monitoring on an ongoing basis at the frequencies each day prescribed below:
| If at any time the residual disinfectant concentration falls below 0.2 mg/l in a system using grab sampling in lieu of continuous monitoring, the system shall take a grab sample every 4 hours until the residual disinfectant concentration is equal to or greater than 0.2 mg/l. |
A public water system that uses a surface water source or a ground water source under the influence of surface water and provides filtration treatment shall monitor in accordance with this paragraph beginning June 29, 1993, or when filtration is installed, whichever is later.
G. Reporting and Recordkeeping Requirements.
(1) A public water system that uses a surface water source and does not provide filtration treatment shall report monthly to the Department the information specified in this paragraph beginning December 31, 1990, unless the Department has determined in writing that filtration is required, in which case the Department may specify alternative reporting requirements, as appropriate, until filtration is in place. A public water system that uses a ground water source under the direct influence of surface water and does not provide filtration treatment shall report monthly to the Department the information specified in this paragraph beginning December 31, 1990, or 6 months after the Department determines that the ground water source is under the direct influence of surface water, whichever is later, unless the Department has determined, in writing, that filtration is required, in which case the Department may specify alternative reporting requirements, as appropriate, until filtration is in place.
(a) Source water quality information shall be reported to the Department within 10 days after the end of each month the system serves water to the public. Information that shall be reported includes:
(ii) The number of fecal and/or total coliform samples, whichever are analyzed during the month (if a system monitors for both, only fecal coliforms must be reported), the dates of sample collection, and the dates when the turbidity level exceeded 1 NTU.
(iii) The number of samples during the month that had equal to or less than 20⁄100 ml fecal coliforms and/or equal to or less than 100⁄100 ml total coliforms, whichever are analyzed.
(vi) The percentage of samples that had equal to or less than 20⁄100 ml fecal coliforms or equal to or less than 100⁄100 ml total coliforms, whichever are analyzed, during the previous six months the system served water to the public.
(vii) The maximum turbidity level measured during the month, the date(s) of occurrence for any measurement(s) which exceeded 5 NTU, and the date(s) the occurrence(s) was reported to the Department.
(viii) For the first 12 months of recordkeeping, the dates and cumulative number of events during which the turbidity exceeded 5 NTU, and after one year of recordkeeping for turbidity measurements, the dates and cumulative number of events during which the turbidity exceeded 5 NTU in the previous 12 months the system served water to the public.
(b) Disinfection information specified in R.61-58.10(F)(2) shall be reported to the Department within 10 days after the end of each month the system serves water to the public. Information that shall be reported includes:
(ii) The date and duration of each period when the residual disinfectant concentration in water entering the distribution system fell below 0.2 mg/l and when the Department was notified of the occurrence.
(iii) The daily residual disinfectant concentration(s) (in mg/l) and disinfectant contact time(s) (in minutes) used for calculating the CT value(s).
(vi) The daily CTcalc and CTcalc/CT99.9 values for each disinfectant measurement or sequence and the sum of all CTcalc/CT99.9 values [radicle (CTcalc/CT99.9] before or at the first customer.
(vii) The daily determination of whether disinfection achieves adequate Giardia cyst and virus inactivation, i.e., whether (CTcalc/CT99.9) is at least 1.0 or, where disinfectants other than chlorine are used, other indicator conditions that the Department determines are appropriate, are met.
(viii) The following information on the samples taken in the distribution system in conjunction with total coliform monitoring pursuant to R.61-58.10(D):
(F) For the current and previous month the system served water to the public, the value of “V” in the following formula:
| where: | |||
| a= | the value in paragraph (1)(b)(viii)(A) of | ||
| this section; | |||
| b= | the value in paragraph (1)(b)(viii)(B) | ||
| of this section; | |||
| c= | the value in paragraph (1)(b)(viii)(C) of | ||
| this section; | |||
| d= | the value in paragraph (1)(b)(viii)(D) | ||
| of this section; and | |||
| e= | the value in paragraph (1)(b)(viii)(E) of | ||
| this section. |
(d) No later than October 10 of each year, each system shall provide to the Department a report on the on-site inspection conducted during that year pursuant to R.61-58.10(C) (2)(c), unless the on-site inspection was conducted by the Department. If the inspection was conducted by the Department, the Department shall provide a copy of its report to the public water system.
(ii) If at any time the turbidity exceeds 5 NTU, the system shall inform the Department as soon as possible, but no later than the end of the next business day.
(iii) If at any time the residual falls below 0.2 mg/l in the water entering the distribution system, the system shall notify the Department as soon as possible, but no later than by the end of the next business day. The system also shall notify the Department by the end of the next business day whether or not the residual was resorted to at least 0.2 mg/l within 4 hours.
(e)(i) Each system, upon discovering that a waterborne disease outbreak potentially attributable to that water system has occurred, shall report that occurrence to the Department as soon as possible, but no later than by the end of the next business day.
(2) A public water system that uses a surface water source or a ground water source under the direct influence of surface water and provides filtration treatment shall report monthly to the Department the information specified in this paragraph beginning June 29, 1993, or when filtration is installed, whichever is later.
(a) Turbidity measurements as required by R.61-58.10(F)(3)(a) shall be reported within 10 days after the end of each month the system serves water to the public. Information that shall be reported includes:
(ii) 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 R.61-58.10(E) for the filtration technology being used.
(iii) The date and value of any turbidity measurements taken during the month which exceed 5 NTU.
(b) Disinfection information specified in R.61-58.10(F)(3) shall be reported to the Department within 10 days after the end of each month the system serves water to the public. Information that shall be reported includes:
(ii) The date and duration of each period when the residual disinfectant concentration in water entering the distribution system fell below 0.2 mg/l and when the Department was notified of the occurrence.
(iii) The following information on the samples taken in the distribution system in conjunction with total coliform monitoring pursuant to R.61-58.10(D):
(F) For the current and previous month the system serves water to the public, the value of “V” in the following formula:
| where | |||
| a= | the value in paragraph (2)(b)(iii)(A) of | ||
| this section; | |||
| b= | the value in paragraph (2)(b)(iii)(B) of | ||
| this section; | |||
| c= | the value in paragraph (2)(b)(iii)(C) of | ||
| this section; | |||
| d= | the value in paragraph (2)(b)(iii)(D) of | ||
| this section; and | |||
| e= | the value in paragraph (2)(b)(iii)(E) of | ||
| this section. |
(iv) A system need not report the data listed in paragraph (2)(b)(i) of this section if all data listed in paragraphs (2)(b)(i)-(iii) of this section remain on file at the system and the Department determines that the system has submitted all the information required by paragraphs (2)(b)(i)-(iii) of this section for at least 12 months.
(c)(i) Each system, upon discovering that a waterborne disease outbreak potentially attributable to that water system has occurred, shall report that occurrence to the Department as soon as possible, but no later than by the end of the next business day.
(ii) If at any time the turbidity exceeds 5 NTU, the system shall inform the Department as soon as possible, but no later than the end of the next business day.
(iii) If at any time the residual falls below 0.2 mg/l in the water entering the distribution system, the system shall notify the Department as soon as possible, but no later than by the end of the next business day. The system also shall notify the Department by the end of the next business day whether or not the residual was restored to at least 0.2 mg/l within 4 hours.
H. Enhanced Filtration and Disinfection—Systems Serving 10,000 or More People (Interim Enhanced Surface Water Treatment Rule)
(1) General requirements.
(a) The requirements of these regulations constitute national primary drinking water regulations. These regulations establish requirements for filtration and disinfection that are in addition to criteria under which filtration and disinfection are required under Sections B through G above. The requirements of this section are applicable to 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 serving at least 10,000 people, beginning January 1, 2002 unless otherwise specified. These regulations establish or extend treatment technique requirements in lieu of maximum contaminant levels for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, Cryptosporidium, and turbidity. Each public water system supplied by a surface water source or a ground water source under the direct influence of surface water system serving at least 10,000 people must provide treatment of its source water that complies with these treatment technique requirements and are in addition to those identified in Sections B through G above. The treatment technique requirements consist of installing and properly operating water treatment processes which reliably achieve:
(b) A public water system subject to the requirements of these regulations is considered to be in compliance with the requirements of paragraph (1) of this section if:
(2) Criteria for avoiding filtration.
(a) Site-specific conditions. In addition to site-specific conditions in R.61-58.10(C)(2), systems must maintain the watershed control program under R.61-58.10(C)(2)(b) to minimize the potential for contamination by Cryptosporidium oocysts in the source water. The watershed control program must, for Cryptosporidium:
In addition to the requirements of R.61-58.10(C), a public water system subject to the requirements of this section that does not provide filtration must meet all of the conditions of paragraphs (2)(a) and (2)(b) of this section.
(3) Disinfection profiling and benchmarking.
(b) Disinfection profiling.
(ii) The system must monitor daily for a period of twelve (12) consecutive calendar months to determine the total logs of inactivation for each day of operation, based on the CT99.9 values in Tables 1.1—1.6, 2.1, and 3.1 of R.61-58.10.F(2), as appropriate, through the entire treatment plant. This system must begin this monitoring not later than March 16, 2000. As a minimum, the system with a single point of disinfectant application prior to entrance to the distribution system must conduct the monitoring in paragraphs (3)(b)(ii) (A) through (D) of this section. A system with more than one point of disinfectant application must conduct the monitoring in paragraphs (3)(b)(i) through (iv) of this section for each disinfection segment. The system must monitor the parameters necessary to determine the total inactivation ratio, using EPA approved analytical methods specified in 40 CFR 141, as follows:
(D) The residual disinfectant concentration(s) (“C”) of the water before or at the first customer and prior to each additional point of disinfection must be measured each day during peak hourly flow.
(iii) In lieu of the monitoring conducted under the provisions of paragraph (b)(ii) of this section to develop the disinfection profile, the system may elect to meet the requirements of paragraph (b)(iii)(A) of this section. In addition to the monitoring conducted under the provisions of paragraph (b)(ii) of this section to develop the disinfection profile, the system may elect to meet the requirements of paragraph (b)(iii)(B) of this section.
(iv) If the system uses only one point of disinfectant application, the system may determine the total inactivation ratio for the disinfection segment based on either of the methods in paragraph (3)(b)(iv)(A) or (3)(b)(iv)(B) of this section.
(vi) The system must determine the total logs of inactivation by multiplying the value calculated in paragraph (b)(iv)(A) or (B) of this section by 3.0.
(vii) A system that uses either chioramines or ozone for primary disinfection must also calculate the logs of inactivation for viruses using a method approved by the Department.
(viii) The system must retain disinfection profile data in graphic form, as a spreadsheet, or in some other format acceptable to the Department for review as part of the sanitary survey.
(c) Disinfection Benchmarking
(i) Any system required to develop a disinfection profile under the provisions of paragraphs (3)(a) and (3)(b) of this section and that decides to make a significant change to its disinfection practice must consult with the Department prior to making such change. Significant changes to disinfection practice are:
(ii) Any system that is modifying its disinfection practice must calculate its disinfection benchmark using the following procedure:
(B) The disinfection benchmark is the lowest monthly average value (for systems with one year of profiling data) or average of lowest monthly average values (for systems with more than one year of profiling data) of the monthly logs of Giardia lamblia inactivation in each year of profiling data.
(iii) A system that uses either chloramines or ozone for primary disinfection must also calculate the disinfection benchmark for viruses using a method approved by the Department.
(iv) The system must submit information in paragraphs (3)(c)(iv)(A) through (C) of this section to the Department as part of its consultation process.
(4) Filtration
(a) Conventional filtration treatment or direct filtration.
(ii) The turbidity level of representative samples of a system’s filtered water must at no time exceed one (1) NTU, measured as specified in Section F(1)(d) and (3)(a) above.
(iii) A system that uses lime softening may acidify representative samples prior to analysis using a protocol approved by the Department.
(b) Filtration technologies other than conventional filtration treatment, direct filtration, slow sand filtration, or diatomaceous earth filtration.
A public water system may use a filtration technology not listed in paragraph (4)(a) of this section or in R.61-58.10(E) (2) or (3) if it demonstrates to the Department, using pilot plant studies or other means, that the alternative filtration technology, in combination with disinfection treatment that meets the requirements of R.61-58.10(D), consistently achieves 99.9 percent removal and/or inactivation of Giardia lamblia cysts and 99.99 percent removal and/or inactivation of viruses, and 99 percent removal of Cryptosporidium oocysts, and the Department approves the use of the filtration technology. For each approval, the Department will set turbidity performance requirements that the system must meet at least 95 percent of the time and that the system may not exceed at any time at a level that consistently achieves 99.9 percent removal and/or inactivation of Giardia lamblia cysts, 99.99 percent removal and/or inactivation of viruses, and 99 percent removal of Cryptosporidium oocysts.
A public water system subject to the requirements of this section that does not meet all of the criteria in Section C above, and paragraph (2) of this section for avoiding filtration must provide treatment consisting of both disinfection, as specified in Section D above, and filtration treatment which complies with the requirements of paragraph 4(a) or 4(b) of this section or Section E (2) or (3) above, by December 31, 2001.
(5) Filtration sampling requirements
(6) Reporting and recordkeeping requirements.
(a) Turbidity measurements as required by paragraph (4) of this section must be reported within 10 days after the end of each month the system serves water to the public. Information that must be reported includes:
(ii) 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 paragraph (4)(a) or (4)(b) of this section.
(iii) The date and value of any turbidity measurements taken during the month which exceed 1 NTU for systems using conventional filtration treatment or direct filtration, or which exceed the maximum level set by the Department under paragraph (4)(b) of this section.
(b) Systems must maintain the results of individual filter monitoring taken under paragraph (5) of this section for at least three years. Systems must report that they have conducted individual filter turbidity monitoring under paragraph (5) of this section within 10 days after the end of each month the system serves water to the public. Systems must report individual filter turbidity measurement results taken under paragraph (5) of this section within 10 days after the end of each month the system serves water to the public only if measurements demonstrate one or more of the conditions in paragraphs (6)(b)(i) through (iv) of this section. Systems that use lime softening may apply to the Department for alternative exceedance levels for the levels specified in paragraphs (6)(b)(i) through (iv) of this section if they can demonstrate that higher turbidity levels in individual filters are due to lime carryover only and not due to degraded filter performance.
(ii) For any individual filter that has a measured turbidity level of greater than 0.5 NTU in two consecutive measurements taken 15 minutes apart at the end of the first four hours of continuous filter operation after the filter has been backwashed or otherwise taken offline, the system must report the filter number, the turbidity, and the date(s) on which the exceedance occurred. In addition, the system must either produce a filter profile for the filter within 7 days of the exceedance (if the system is not able to identify an obvious reason for the abnormal filter performance) and report that the profile has been produced or report the obvious reason for the exceedance.
(iii) For any individual filter that has a measured turbidity level of greater than 1.0 NTU in two consecutive measurements taken 15 minutes apart at any time in each of three consecutive months, the system must report the filter number, the turbidity measurement, and the date(s) on which the exceedance occurred. In addition, the system must conduct a self-assessment of the filter within 14 days of the exceedance and report that the self-assessment was conducted. 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.
(c) Additional reporting requirements.
In addition to the reporting and recordkeeping requirements in Section G above, a public water system subject to the requirements of this section that provides conventional filtration treatment or direct filtration must report monthly to the Department the information specified in paragraphs (6)(a) and (6)(b) of this section beginning December 31, 2001. In addition to the reporting and recordkeeping requirements in Section G above, a public water system subject to the requirements of this section that provides filtration approved under paragraph (4)(b) of this section must report monthly to the Department the information specified in paragraph (a) of this section beginning December 31, 2001. The reporting in paragraph (6)(a) of this section is in lieu of the reporting specified in Section G above.
I. Enhanced Filtration and Disinfection—Systems Serving Fewer Than 10,000 People (Long Term 1 Enhanced Surface Water Treatment Rule)
(1) General Requirements
(a) The requirements of this regulation constitute national primary drinking water regulations. These regulations establish requirements for filtration and disinfection that are in addition to criteria under which filtration and disinfection are required for systems with surface water sources or ground water sources under the influence of surface water. This regulation establishes or extends treatment technique requirements in lieu of maximum contaminant levels for the following contaminants: Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, Cryptosporidium and turbidity. The treatment technique requirements consist of installing and properly operating water treatment processes which reliably achieve:
(b) Who is subject to the requirements of this section?—You are subject to these requirements if your system:
(ii) Uses surface water or GWUDI as a source; and
(iii) Serves fewer than 10,000 persons.
(d) What does this regulation require?—There are seven (7) requirements of this subpart, and you must comply with all requirements that are applicable to your system. These requirements are:
(ii) If your system is an unfiltered system, you must comply with the updated watershed control requirements described in paragraph (3) of this section;
(iii) If your system is a community or non-transient non-community water systems you must develop a disinfection profile as described in paragraph (4) of this section;
(vi) If your system is a filtered system that uses conventional or direct filtration, you must comply with the individual filter turbidity requirements as described in paragraph (7) of this section; and,
(vii) You must comply with the applicable reporting and recordkeeping requirements as described in paragraph (8) of this section.
(2) Finished Water Reservoirs
(3) Additional Watershed Control Requirements for Unfiltered Systems
(b) What updated watershed control requirements must my unfiltered system implement to continue to avoid filtration?—Your system must take any additional steps necessary to minimize the potential for contamination by Cryptosporidium oocysts in the source water. Your system’s watershed control program must, for Cryptosporidium:
(4) Disinfection Profile
(c) How does my system develop a Disinfection Profile and when must it begin?—A disinfection profile consists of three steps:
(ii) Second, your system must use this data to calculate weekly log inactivation as discussed in paragraphs (4)(e) and (f) of this section.
(iii) Third, your system must use these weekly log inactivations to develop a disinfection profile as specified in paragraph (4)(g) of this section.
(d) What data must my system collect to calculate a Disinfection Profile?—Your system must monitor the following parameters to determine the total log inactivation using the analytical methods in Section F, once per week on the same calendar day, over twelve (12) consecutive months:
(ii) If your system uses chlorine, the pH of the disinfected water at each residual disinfectant concentration sampling point during peak hourly flow;
(iii) The disinfectant contact time(s) (‘T’) during peak hourly flow; and
(e) How does my system use this data to calculate an inactivation ratio? Use the tables in R-61.58.10.F(1)(c)(v) to determine the appropriate CT99.9 value. Calculate the total inactivation ratio as follows, and multiply the value by 3.0 to determine log inactivation of Giardia lamblia:
| If your system * * * | Your system must determine * * * | ||
| (a) | Uses only one point of disinfectant application | (1) | One inactivation ratio (CTcalc/CT99.9) before or at the first customer during peak hourly flow or |
| (2) | Successive CTcalc/CT99.9 values, representing sequential inactivation ratios, between the point of disinfectant application and a point before or at the first customer during peak hourly flow. Under this alternative, your 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 (ΣCTcalc/CT99.9). | ||
| (b) | Uses more than one point of disinfectant application before the first customer | The (CTcalc/CT99.9) 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 using the procedure specified in paragraph (a)(2) of this section. |
(5) Disinfection Benchmark
(b) What are significant changes to disinfection practice?—Significant changes to disinfection practice include:
(ii) Changes to the disinfectant(s) used in the treatment plant;
(iii) Changes to the disinfection process; or
(c) What must my system do if we are considering a significant change to disinfection practices?—If your system is considering a significant change to its disinfection practice, your system must calculate a disinfection benchmark(s) as described in paragraphs (5)(c) and (d) of this section, and provide the benchmark(s) to the Department. Your system may only make a significant disinfection practice change after consulting with the Department for approval. Your system must submit the following information to the Department as part of the consultation and approval process:
(ii) The disinfection profile for Giardia lamblia (and, if necessary, viruses) and disinfection benchmark;
(iii) An analysis of how the proposed change will affect the current levels of disinfection; and
(d) How is the Disinfection Benchmark calculated?—If your system is making a significant change to its disinfection practice, it must calculate a disinfection benchmark using the procedure specified in the following table.
| To calculate a disinfection benchmark your system must perform the following steps | |||
| Step 1: | Using the data your system 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. | ||
| Step 2: | Determine the lowest monthly average value out of the twelve (12) values. This value becomes the disinfection benchmark. |
(6) Combined Filter Effluent Requirements
(b) What strengthened combined filter effluent turbidity limits must my system meet?—Your system must meet two strengthened combined filter effluent turbidity limits.
(i) The first combined filter effluent turbidity limit is a “95th percentile” turbidity limit that your system must meet in at least ninety five (95) percent of the turbidity measurements taken each month. Measurements must continue to be taken as described in Section F(1) and (3). Monthly reporting must be completed according to paragraph (8) of this section. The following table describes the required limits for specific filtration technologies.
| If your system consists of * * * | Your 95th percentile turbidity value is * * * |
| (1) Conventional Filtration or Direct Filtration | 0.3 NTU |
| (2) All other ‘Alternative’ Filtration | A value determined by the Department (not to exceed 1 NTU) based on the demonstration described in paragraph (6)(c)of this section. |
(ii) The second combined filter effluent turbidity limit is a “maximum” turbidity limit which your system may at no time exceed during the month. Measurements must continue to be taken as described in Sections F(1) and C. Monthly reporting must be completed according to paragraph (8) of this section The following table describes the required limits for specific filtration technologies.
| If your system consists of * * * | Your maximum turbidity value is * * * |
| (1) Conventional Filtration or Direct Filtration. | 1 NTU |
| (2) All other ‘Alternative’ Filtration | A value determined by the Department (not to exceed 5 NTU) based on the demonstration as described in paragraph (6)(c) of this section. |
(c) My system consists of “alternative filtration” and is required to conduct a demonstration—what is required of my system and how does the Department establish my turbidity limits?-
(i) If your system consists of alternative filtration (filtration other than slow sand filtration, diatomaceous earth filtration, conventional filtration, or direct filtration) you are required to conduct a demonstration (see tables in paragraph (6)(b) of this section). Your system must demonstrate to the Department, using pilot plant studies or other means, that your system’s filtration, in combination with disinfection treatment, consistently achieves:
(7) Individual Filter Turbidity Requirements
(a) Is my system subject to individual filter turbidity requirements?—If your system is a surface water system or a ground water system under the direct influence of surface water serving fewer than 10,000 people and utilizing conventional filtration or direct filtration, you must conduct continuous monitoring of turbidity for each individual filter at your system. The following requirements apply to continuous turbidity monitoring:
(ii) Calibration of turbidimeters must be conducted using procedures specified by the manufacturer;
(iii) Results of turbidity monitoring must be recorded at least every fifteen (15) minutes;
(d) What follow-up action is my system required to take based on continuous turbidity monitoring? Follow-up action is required according to the following tables:
| If * * * | Your system must * * * | ||
| (a) | The turbidity of an individual filter (or the turbidity of combined filter effluent (CFE) for systems with 2 filters that monitor CFE in lieu of individual filters) exceeds 1.0 NTU in two consecutive recordings 15 minutes apart. | Report to the Department by the 10th 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). | |
| If a system was required to report to the Department * * * | Your system must * * * | ||
| (b) | 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 2 filters that monitor CFE in lieu of individual filters). | 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 CPE as specified in paragraph (c) of this section was required. Systems with 2 filters that monitor CFE in lieu of individual filters must 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. | |
| (c) | For two months in a row and turbidity exceeded 2.0 NTU in 2 consecutive recordings 15 minutes apart at the same filter (or CFE for systems with 2 filters that monitor CFE in lieu of individual filters). | Arrange to have a comprehensive performance evaluation (CPE) conducted by the Department or a third party approved by the Department not 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 or a third party approved by the Department within the 12 prior months or the system and the Department are jointly participating in an ongoing Comprehensive Technical Assistance (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. |
(8) Reporting and Recordkeeping Requirements
(a) What does this section require that my system report to the Department? This section requires your system to report several items to the Department. The following table describes the items which must be reported and the frequency of reporting. Your system is required to report the information described in the following table, if it is subject to the specific requirement shown in the first column.
| Corresponding requirement | Description of information to report | Frequency |
| (a) Combined Filter Effluent Requirements. (paragraphs (6)(a) through (d) of this section). | (1) The total number of filtered water turbidity measurements taken during the month. | By the 10th of the following month. |
| (2) The number and percentage of filtered water turbidity measurements taken during the month which are less than or equal to your system’s required 95th percentile limit. | By the 10th of the following month. | |
| (3) The date and value of any turbidity measurements taken during the month which exceed the maximum turbidity value for your filtration system. | By the 10th of the following month | |
| (b) Individual Turbidity Requirements. (paragraph (7)(a) through (e) of this section). | (1) That your system conducted individual filter turbidity monitoring during the month. | By the 10th of the following month. |
| (2) The filter number(s), corresponding date(s), and the turbidity value(s) which exceeded 1.0 NTU during the month, and cause (if known) for the exceedance(s), but only if 2 consecutive measurements exceeded 1.0 NTU. | By the 10th of the following month. | |
| (3) If a self-assessment is required, the date that it was triggered and the date that it was completed. | By the 10th of the following month (or 14 days after the self-assessment was triggered only if the self-assessment was triggered during the last four days of the month) | |
| (4) If a CPE is required, that the CPE is required and the date that it was triggered. | By the 10th of the following month. | |
| (5) Copy of completed CPE report | Within 120 days after the CPE was triggered. | |
| (c) Disinfection Profiling..... (paragraphs (4)(a) through (g) of this section) | (1) Results of optional monitoring which show TTHM levels 0.064 mg/L and HAA5 levels 0.048 mg/L (only if your system wishes to forgo profiling) or that your system has begun disinfection profiling. | (i) For systems serving 500-9,999 by July 1, 2003; (ii) For systems serving fewer than 500 by January 1, 2004. |
| (d) Disinfection Benchmarking (paragraph (5)(a) through (e) of this section) | (1) A description of the proposed change in disinfection, your 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 your system is considering a significant change to its disinfection practice. |
(b) What records does this regulation require my system to keep?—Your system must keep several types of records based on the requirements of this regulation, in addition to recordkeeping requirements under Section G. The following table describes the necessary records, the length of time these records must be kept, and for which requirement the records pertain. Your system is required to maintain records described in this table, if it is subject to the specific requirement shown in the first column.
| Corresponding requirement | Description of necessary records | Duration of time records must be kept |
| (a) Individual Filter Turbidity Requirements | ||
| (paragraphs (7)(a) through (e) of this section) | Results of individual filter monitoring | At least 3 years. |
| (b) Disinfection Profiling | ||
| (paragraphs (4)(a) through (g) of this section) | Results of Profile (including raw data and analysis) | Indefinitely. |
| (c) Disinfection Benchmarking | ||
| (paragraphs (5)(a) through (e) of this section) | Benchmark (including raw data and analysis) | Indefinitely. |
J. Recycle Provisions (Filter Backwash Recycling Rule)
(2) Reporting. A system must notify the Department in writing by December 8, 2003, if the system recycles spent filter backwash water, thickener supernatant, or liquids from dewatering processes. This notification must include, at a minimum, the information specified in paragraphs (2)(a) and (b) of this section.
(4) Recordkeeping. The system must collect and retain on file recycle flow information specified in paragraphs (4)(a) through (f) of this section for review and evaluation by the Department beginning June 8, 2004.
K. Enhanced Treatment for Cryptosporidium (Long Term 2 Surface Water Treatment Rule)
(1) General Requirements
(b) Applicability.
(ii) The requirements of R.61-58.10.K for filtered systems apply to systems required by State Primary Drinking Water Regulations to provide filtration treatment, whether or not the system is currently operating a filtration system.
(iii) The requirements of R.61-58.10.K for unfiltered systems apply only to unfiltered systems that timely met and continue to meet the filtration avoidance criteria in R.61-58.10.A through I, as applicable.
The requirements of R.61-58.10.K apply to all subpart H systems.
(c) Requirements.
(ii) Systems that plan to make a significant change to their disinfection practice must develop disinfection profiles and calculate disinfection benchmarks, as described in R.61-58.10.K(9) and (10).
(iii) Filtered systems must determine their Cryptosporidium treatment bin classification as described in R.61-58.10.K(11) and provide additional treatment for Cryptosporidium, if required, as described in R.61-58.10.K(12). All unfiltered systems must provide treatment for Cryptosporidium as described in R.61-58.10.K(13). Filtered and unfiltered systems must implement Cryptosporidium treatment according to the schedule in R.61-58.10.K(14).
(vi) Systems must comply with the applicable recordkeeping and reporting requirements described in R.61-58.10.K(22) through R.61-58.10.K(23).
(vii) Systems must address significant deficiencies identified in sanitary surveys performed by EPA as described in R.61-58.10.K(24).
Systems subject to R.61-58.10.K must comply with the following requirements:
(2) Source Water Monitoring.
(a) Initial Source Monitoring.
(ii) Unfiltered systems serving at least 10,000 people must sample their source water for Cryptosporidium at least monthly for 24 months.
(iii) E.Coli Monitoring for Filtered Systems Serving Fewer Than 10,000 People.
(iv) 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 criteria in (A) through (D) below, based on monitoring conducted under R.61-58.10.K(2)(a)(iii).
(vi) 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.
(vii) Systems may sample more frequently than required under this section if the sampling frequency is evenly spaced throughout the monitoring period.
Systems must conduct the following monitoring on the schedule in R.61-58.10.K(2)(c) unless they meet the monitoring exemption criteria in R.61-58.10.K(2)(d).
(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 R.61-58.10.K(2)(a), unless they meet the monitoring exemption criteria in R.61-58.10.K(2)(d). Systems must conduct this monitoring on the schedule in R.61-58.10.K(2)(c).
(c) Monitoring Schedule
(ii) Systems that serve from 50,000 to 99,999 people must begin the first round of source water monitoring no later than the month beginning April 1, 2007, and must begin the second round of source water monitoring no later than the month beginning October 1, 2015.
(iii) Systems that serve from 10,000 to 49,999 people must begin the first round of source water monitoring no later than the month beginning April 1, 2008, and must begin the second round of source water monitoring no later than the month beginning October 1, 2016.
Systems must begin the monitoring required in R.61-58.10.K(2)(a) and (b) no later than the month beginning with the date listed in R.61-58.10.K(2)(c)(i) through (v).
(d) Monitoring Avoidance.
(ii) Unfiltered systems are not required to conduct source water monitoring under R.61-58.10.K 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 per L in R.61-58.10.K(13).
(iii) If a system chooses to provide the level of treatment in R.61-58.10.K(2)(d)(1) or (2), as applicable, rather than start source water monitoring, the system must notify the Department in writing no later than the date the system is otherwise required to submit a sampling schedule for monitoring under R.61-58.10.K(3). Alternatively, a system may choose to stop sampling at any point after it has initiated monitoring if it notifies the Department 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 R.61-58.10.K(14).
(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 R.61-58.10.K with the following modifications:
(f) New Sources.
(ii) The requirements of R.61-58.10.K(2)(f) apply to subpart H systems that begin operation after the monitoring start date applicable to the system’s size under R.61-58.10.K(2)(c).
(iii) The system must begin a second round of source water monitoring no later than 6 years following initial bin classification under R.61-58.10.K(11) or determination of the mean Cryptosporidium level under R.61-58.10.K(13), as applicable.
(h) Grandfathering Monitoring Data.
Systems may use (grandfather) monitoring data collected prior to the applicable monitoring start date in R.61-58.10.K(2)(c) to meet the initial source water monitoring requirements in R.61-58.10.K(2)(a). 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 R.61-58.10.K(8).
(3) Sampling Schedules.
(a) Systems required to conduct source water monitoring under R.61-58.10.K(2) must submit a sampling schedule that specifies the calendar dates when the system will collect each required sample.
(ii) Electronic Submittal of Sample Schedules for Systems Serving at Least 10,000 People.
(B) 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.
(iii) Systems serving fewer than 10,000 people must submit their sampling schedules for the initial round of source water monitoring under R.61-58.10.K(2)(a) to the Department.
(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 R.61-58.10.K(3)(b)(i) or (ii) applies.
(ii) Replacement Samples.
(4) Sampling Locations.
(b) Sampling Prior to Chemical Treatment.
(d) Bank Filtration.
(e) Multiple Sources.
(ii) 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 R.61-58.10.K(4)(e)(ii)(A) or (B) for sample analysis.
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 R.61-58.10.K(4)(e)(i) or (ii). The use of multiple sources during monitoring must be consistent with routine operational practice.
(f) Additional Requirements.
Systems must submit a description of their sampling location(s) to the Department at the same time as the sampling schedule required under R.61-58.10.K(3). 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 Department does not respond to a system regarding sampling location(s), the system must sample at the submitted location(s).
(5) Analytical Methods.
(a) Cryptosporidium. Systems must analyze for Cryptosporidium using EPA-approved methods listed in 40 CFR 141.704.
(ii) (A) Matrix spike (MS) samples, must be spiked and filtered by a laboratory approved for Cryptosporidium analysis under R.61-58.10.K(6).
(B) If the volume of the matrix spike sample is greater than 10 L, the system may filter all but 10 L of the matrix spike 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.
(iii) Flow cytometer-counted spiking suspensions must be used for matrix spike 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 40 CFR 136.3(a).
(ii) The Department 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 Department 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 Methods 9223B as listed in 40 CFR 136.3(a).
(iii) Samples must be maintained between 0 degrees Celsius and 10 degrees Celsius during storage and transit to the laboratory.
(6) Approved Laboratories
(7) Reporting Source Water Monitoring Results.
(b) Electronic Reporting for Systems Serving at Least 10,000 People.
(e) Systems must report the applicable information in R.61-58.10.K(7)(e)(i) and (ii) for the source water monitoring required under R.61-58.10.K(2).
(i) Systems must report the following data elements for Cryptosporidium analysis: PWS ID, Facility ID, Sample collection date, Sample type (field or matrix spike), Sample volume filtered (to nearest one quarter of a L), Whether or not 100 percent of the filtered volume was examined, and the Number of oocysts counted.
(8) Grandfathering Previously Collected Data.
(a) Sample Requirements.
(e) Sampling Frequency.
Cryptosporidium samples must have been 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 R.61-58.10.K(3)(b)(i) and (ii) if the system provides documentation of the condition when reporting monitoring results.
(f) Reporting Monitoring Results for Grandfathering.
(ii) Systems must report previously collected monitoring results for grandfathering, along with the associated documentation listed in R.61-58.10.K(8)(f)(ii)(A) through (D), no later than two months after the applicable date listed in R.61-58.10.K(2)(c).
Systems that request to grandfather previously collected monitoring results must report the following information specified in R.61-58.10.K(8)(f)(i) and (ii) by the applicable dates listed. Systems serving at least 10,000 people must report this information to EPA unless the Department approves reporting directly to the Department rather than EPA. Systems serving fewer than 10,000 people must report this information to the Department.
(9) Requirements When Making a Significant Change in Disinfection Practice.
(a) Following the completion of initial source water monitoring under R.61-58.10.K(2)(a), a system that plans to make a significant change to its disinfection practice, as defined in R.61-58.10.K(9)(b), must develop a disinfection profile and calculate a disinfection benchmark for Giardia lamblia and viruses as described in R.61-58.10.K(10). Prior to changing the disinfection practice, the system must notify the Department and must include in this notice the information listed in R.61-58.10.K(9)(a)(i) through (iii).
(ii) A description of the proposed change in disinfection practice.
(iii) An analysis of how the proposed change will affect the current level of disinfection.
(b) Significant changes to disinfection practice are defined as follows:
(ii) Changes to the disinfectant(s) used in the treatment plant;
(iii) Changes to the disinfection process; or
(10) Developing the Disinfection Profile and Benchmark.
(b) Systems with a single point of disinfectant application prior to the entrance to the distribution system must conduct the monitoring in R.61-58.10(K)(10)(b)(i) through (iv). Systems with more than one point of disinfectant application must conduct the monitoring in R.61-58.10(K)(10)(b)(i) through (iv) for each disinfection segment. Systems must monitor the parameters necessary to determine the total inactivation ratio, using analytical methods in 40 CFR 141.74(a).
(ii) For systems using chlorine, the pH of the disinfected water must be measured at each chlorine residual sampling point during peak hourly flow or at an alternative location approved by the Department.
(iii) The disinfectant contact time(s) (t) must be determined during peak hourly flow.
(c) In lieu of conducting new monitoring under R.61-58.10(K)(10)(b), systems may elect to meet the requirements of R.61-58.10(K)(10)(c)(i) or (ii).
(d) Systems must calculate the total inactivation ratio for Giardia lamblia as specified in R.61-58.10(K)(10)(d)(i) through (iii).
(i) 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 R.61-58.10(K)(10)(d)(i)(A) or (B).
(ii) 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 the sum of CTcalc/CT99.9 must be calculated using the method in R.61-58.10.K(10)(d)(i)(B).
(iii) The system must determine the total logs of inactivation by multiplying the value calculated in R.61-58.10.K(10)(d)(i) or (ii) by 3.0.
(e) Systems must use the procedures specified in R.61-58.10.K(10)(e)(i) and (ii) to calculate a disinfection benchmark.
(11) Bin Classification for Filtered Systems.
(b) Cryptosporidium bin concentrations. Bin concentration is the cryptospridium concentration(s) used to determine bin classification
(ii) 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.
(iii) 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.
(c) Filtered systems that are required to monitor under R.61-58.10.K(2) must determine their initial bin classification from the Bin Classification Table that follows and using the Cryptosporidium bin concentration calculated under R.61-58.10.K(11)(a) and (b). The bin classification for filtered systems that serve fewer than 10,000 people and are not required to monitor under R.61-58.10.K(2)(a)(iv)is Bin 1.
Bin Classification Table For Filtered Systems
| Cryptosporidium Concentration | Bin Classification |
| Less than 0.075 oocysts per L | Bin 1 |
| 0.075 to less than 1.0 oocysts per L | Bin 2 |
| 1.0 to less than 3.0 oocysts per L | Bin 3 |
| Greater than or equal to 3.0 oocysts per L | Bin 4 |
(e) Reporting Bin Classifications to the Department.
(ii) Systems must report their bin classification under R.61-58.10.K(11)(d) to the Department 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 R.61-58.10.K(2)(c).
(iii) The bin classification report to the Department must include a summary of source water monitoring data and the calculation procedure used to determine bin classification.
(12) Filtered System Additional Cryptosporidium Treatment Requirements.
(a) Filtered systems must provide the level of additional treatment for Cryptosporidium specified in this paragraph (12)(a) based on their bin classification as determined under R.61-58.10.K(11) and according to the schedule in R.61-58.10.K(14).
Bin Classifications According to Treatment Type1
| Bin Classification | Conventional Filtration (includes 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 | See note 2 |
| Bin 3 | 2-log treatment | 2.5-log treatment | 2-log treatment | See note 3 |
| Bin 4 | 2.5-log treatment | 3-log treatment | 2.5-log treatment | See note 4 |
Notes:
4. As determined by the Department such that the total Cryptosporidium removal and inactivation is at least 5.5-log.
(b) Cryptosporidium Treatment Requirements.
(13) Unfiltered system Cryptosporidium Treatment Requirements.
(a) Determination of Mean Cryptosporidium Level.
(ii) Following completion of the second round of source water monitoring required under R.61-58.10.K(2)(b), unfiltered systems must calculate the arithmetic mean of all Cryptosporidium sample concentrations reported under R.61-58.10.K(2)(b). Systems must report this value to the Department 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 R.61-58.10.K(2)(c).
(iii) 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 R.61-58.10.K(13)(a)(i) or (ii).
(b) Cryptosporidium Inactivation Requirements.
Unfiltered systems must provide the level of inactivation for Cryptosporidium specified in this paragraph (b), based on their mean Cryptosporidium levels as determined under R.61-58.10.K(13)(a) and according to the schedule in R.61-58.10.K(14).
(c) Inactivation Treatment Technology Requirements.
Unfiltered systems must use chlorine dioxide, ozone, or UV as described in R.61-58.10.K(21) to meet the Cryptosporidium inactivation requirements of R.61-58.10.K(13).
(d) Use of Two Disinfectants.
Unfiltered systems must meet the combined Cryptosporidium inactivation requirements of R.61-58.10.K(13) and Giardia lamblia and virus inactivation requirements of R.61-58.10.D(1) 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.
(14) Schedule for compliance with Cryptosporidium Treatment Requirements.
(c) Cryptosporidium treatment compliance dates.
(ii) Systems that serve from 50,000 to 99,999 people must comply with Cryptosporidium treatment requirements no later than October 1, 2012.
(iii) Systems that serve from 10,000 to 49,999 people must comply with Cryptosporidium treatment requirements no later than October 1, 2013.
(15) Requirements for uncovered finished water storage facilities.
(c) Systems must meet the conditions of R.61-58.10.K(15)(c)(i) or (ii) for each uncovered finished water storage facility or be in compliance with a Department-approved schedule to meet these conditions no later than April 1, 2009.
(16) Microbial toolbox options for meeting Cryptosporidium treatment requirements.
(a) Cryptosporidium Treatment Credits.
(b) Microbial Toolbox Summary Treatment Credits and Criteria
(i) Source Protection and Management Toolbox Options
(ii) Pre Filtration Toolbox Options
(C) Bank filtration: 0.5-log credit may be given for a 25-foot setback; 1.0-log credit may be given for a 50-foot setback. The aquifer must be unconsolidated sand consisting of at least 10 percent fines. The average turbidity in the 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 for obtaining and maintaining this credit are detailed in R.61-58.10.K(18)(c).
(iii) Treatment Performance Toolbox Options
(iv) Additional Filtration Toolbox Options
(v) Inactivation Toolbox Options
(17) Source Toolbox Components.
(a) Watershed Control Program.
(ii) Systems must submit to the Department a proposed watershed control plan no later than one year before the applicable treatment compliance date in R.61-58.10.K(14). The Department must approve the watershed control plan for the system to receive treatment credit. The watershed control plan must include the elements in R.61-58.10.K(17)(a)(ii)(A) through (D).
(D) 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.
(iii) 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 R.61-58.10.K(17)(a)(ii) and must specify ongoing and future actions that will reduce source water Cryptosporidium levels.
(v) Systems must complete the actions in R.61-58.10.K(17)(a)(v)(A) through (C) to maintain the 0.5-log credit.
(B) Undergo a watershed sanitary survey every three years for community water systems and every five years for non-community water systems and submit the survey report to the Department. The survey must be conducted according to Department guidelines and by persons approved by the Department.
Systems receive 0.5-log Cryptosporidium treatment credit for implementing a watershed control program that meets the following requirements:
(b) Alternative Source.
(ii) If systems conduct alternative source monitoring under R.61-58.10.K(17)(b)(i), systems must also monitor their current plant intake concurrently as described in R.61-58.10.K(2).
(iii) Alternative source monitoring under R.61-58.10.K(17)(b)(i) must meet the requirements for source monitoring to determine bin classification, as described in R.61-58.10.K(2) through (7). Systems must report the alternative source monitoring results to the Department, along with supporting information documenting the operating conditions under which the samples were collected.
(18) Pre-filtration Treatment Toolbox Components.
(a) Presedimentation.
(ii) The system must continuously add a coagulant to the presedimentation basin.
(iii) The presedimentation basin must achieve the performance criteria in R.61-58.10.K(18)(iii)(A) or (B).
Systems receive 0.5-log Cryptosporidium treatment credit for a presedimentation basin during any month the process meets the criteria in R.61-58.10.K(18)(a).
(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.
(ii) 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.
(iii) Only horizontal and vertical wells are eligible for treatment credit.
(vi) Springs and infiltration galleries are not eligible for treatment credit under R.61-58.10.K(18), but are eligible for credit under R.61-58.10.K(19)(c).
(vii) Bank Filtration Demonstration of Performance.
The Department 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 R.61-58.10.K(18)(c)(i) through (v).
Systems receive Cryptosporidium treatment credit for bank filtration that serves as pretreatment to a filtration plant by meeting the criteria in R.61-58.10.K(18)(c). Systems using bank filtration when they begin source water monitoring under R.61-58.10.K(2)(a) must collect samples as described in R.61-58.10.K(4)(d) and are not eligible for this credit.
(19) Treatment Performance Toolbox Components.
(a) Combined Filter Performance.
Systems using conventional filtration treatment or direct filtration treatment may 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 40 CFR 141.74(a) and (c).
(b) Individual Filter Performance.
(ii) No individual filter may have a measured turbidity greater than 0.3 NTU in two consecutive measurements taken 15 minutes apart.
(iii) Any system that has received treatment credit for individual filter performance and fails to meet the requirements of R.61-58.10.K(19)(b)(i) or (ii) during any month does not receive a treatment technique violation under R.61-58.10.K(12)(c) if the Department determines the following:
Systems using conventional filtration treatment or direct filtration treatment may receive 0.5-log Cryptosporidium treatment credit, which can be in addition to the 0.5-log credit under R.61-58.10.K(19)(a), during any month the system meets the criteria in this paragraph (b). Compliance with these criteria must be based on individual filter turbidity monitoring as described in R.61-58.10.H(5) or R.61-58.10.I(7), as applicable.
(c) Demonstration of Performance.
(ii) The demonstration of performance study must follow a Department-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.
(iii) Approval by the Department 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 Department 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.
The Department may approve Cryptosporidium treatment credit for drinking water treatment processes based on a demonstration of performance study that meets the criteria in this paragraph (c). This treatment credit may be greater than or less than the prescribed treatment credits in R.61-58.10.K(12) or R.61-58.10.K(18) through (21) and may be awarded to treatment processes that do not meet the criteria for the prescribed credits.
(20) Additional Filtration Toolbox Components.
(a) Bag and Cartridge Filters.
(ii) 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.
(iii) 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.
(iv) 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 = 10,000 x (Filtrate Detection Limit)
(vi) Each filter evaluated must be tested for a duration sufficient to reach 100 percent of the terminal pressure drop. This maximum pressure drop is the pressure drop under which the filter may be used to comply with the requirements of R.61-58.10(K).
(vii) 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:
LRV = LOG10(Cf)-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 Cp must be set equal to the detection limit.
(viii) 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. A log removal value must be calculated for each of these challenge periods for each filter tested. The log removal value for the filter must be assigned the value of the minimum log removal value observed during the three challenge periods for that filter.
With Department approval, systems may 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 R.61-58.10.K(20)(a)(i) through (x). To be eligible for this credit, systems must report the results of challenge testing that meets the requirements of R.61-58.10.K(20)(a)(ii) through (ix) to the Department. The filters must treat the entire plant flow taken from a subpart H source.
(b) Membrane Filtration.
(i) Systems may receive Cryptosporidium treatment credit for membrane filtration that meets the criteria of this paragraph (b). Membrane cartridge filters that meet the definition of membrane filtration in R.61-58.B are eligible for this credit. The level of treatment credit a system receives is equal to the lower of the values determined under R.61-58.10.K(20)(b)(i)(A) and (B).
(ii) 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 Department. Challenge testing must be conducted according to the criteria in R.61-58.10.K(20)(b)(ii)(A) through (G). Systems may use data from challenge testing conducted prior to January 5, 2006 if the prior testing was consistent with the criteria in R.61-58.10.K(20)(b)(ii)(A) through (G).
(C) 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 = 3,160,000 x (Filtrate Detection Limit)
(E) 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 Cp is set equal to the detection limit for the purpose of calculating the log removal value. A log removal value must be calculated for each membrane module evaluated during the challenge test.
(H) 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 quality control release value, additional challenge testing to demonstrate a new removal efficiency and quality control release value must be conducted and submitted to the Department.
(iii) 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 R.61-58.10.K(20)(b)(iii)(A) through (F). 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).
(C) The direct integrity test must have a sensitivity sufficient to verify the log treatment credit awarded to the membrane filtration process by the Department, 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 R.61-58.10.K(20)(b)(iii)(C)(1) or (2) as applicable to the type of direct integrity test the system uses.
(1) 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 x 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.
(2) 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) Indirect integrity monitoring. Systems must conduct continuous indirect integrity monitoring on each membrane unit according to the criteria in R.61-58.10.K(20)(b)(iv)(A) through (E). 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 R.61-58.10.K(20)(b)(iii)(A) through (E) is not subject to the requirements for continuous indirect integrity monitoring. Systems must submit a monthly report to the Department summarizing all continuous indirect integrity monitoring results triggering direct integrity testing and the corrective action that was taken in each case.
(d) Slow Sand Filtration (as Secondary Filter).
With Department approval, systems may 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 Department 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.
(21) Inactivation Toolbox Components.
(a) Calculation of CT Values.
(b) CT values for Chlorine Dioxide and Ozone.
(i) Systems may receive the Cryptosporidium treatment credit listed in the following table by meeting the corresponding chlorine dioxide CT value for the applicable water temperature, as described in R.61-58.10.K(21)(a).
CT Values (mg-min/L) for Cryptosporidium Inactivation by Chlorine Dioxide
| Water Temperature (degrees C) | |||||||||||
| Log Credit | Less than or equal to 0.5 | 1 | 2 | 3 | 5 | 7 | 10 | 15 | 20 | 25 | 30 |
| 0.25 | 159 | 153 | 140 | 128 | 107 | 90 | 69 | 45 | 29 | 19 | 12 |
| 0.5 | 319 | 305 | 279 | 256 | 214 | 180 | 138 | 89 | 58 | 38 | 24 |
| 1.0 | 637 | 610 | 558 | 511 | 429 | 360 | 277 | 179 | 116 | 75 | 49 |
| 1.5 | 956 | 915 | 838 | 767 | 643 | 539 | 415 | 268 | 174 | 113 | 73 |
| 2.0 | 1275 | 1220 | 1117 | 1023 | 858 | 719 | 553 | 357 | 232 | 150 | 98 |
| 2.5 | 1594 | 1525 | 1396 | 1278 | 1072 | 899 | 691 | 447 | 289 | 188 | 122 |
| 3.0 | 1912 | 1830 | 1675 | 1534 | 1286 | 1079 | 830 | 536 | 347 | 226 | 147 |
Note: Systems may use this equation to determine log credit between the indicated values: Log credit = (0.001506 X (1.09116)Temp) X CT.
(ii) Systems may receive the Cryptosporidium treatment credit listed in the following table by meeting the corresponding ozone CT values for the applicable water temperature, as described in R.61-58.10.K(21)(a).
CT Values (mg-min/L) for Cryptosporidium Inactivation by Ozone
| Water Temperature (degrees C) | |||||||||||
| Log Credit | Less than or equal to 0.5 | 1 | 2 | 3 | 5 | 7 | 10 | 15 | 20 | 25 | 30 |
| 0.25 | 6 | 5.8 | 5.2 | 4.8 | 4.0 | 3.3 | 2.5 | 1.6 | 1.0 | 0.6 | .39 |
| 0.5 | 12 | 12 | 10 | 9.5 | 7.9 | 6.5 | 4.9 | 3.1 | 2.0 | 1.2 | .78 |
| 1.0 | 24 | 23 | 21 | 19 | 16 | 13 | 9.9 | 6.2 | 3.9 | 2.5 | 1.6 |
| 1.5 | 36 | 35 | 31 | 29 | 24 | 20 | 15 | 9.3 | 5.9 | 3.7 | 2.4 |
| 2.0 | 48 | 46 | 42 | 38 | 32 | 26 | 20 | 12 | 7.8 | 4.9 | 3.1 |
| 2.5 | 60 | 58 | 52 | 48 | 40 | 33 | 25 | 16 | 9.8 | 6.2 | 3.9 |
| 3.0 | 72 | 69 | 63 | 57 | 47 | 39 | 30 | 19 | 12 | 7.4 | 4.7 |
Systems may use this equation to determine log credit between the indicated values: Log credit = (0.0397 X (1.09757)Temp) X CT
(c) Site-Specific Study.
The Department may approve alternative chlorine dioxide or ozone CT values to those listed in R.61-58.10.K(21)(b) on a site-specific basis. The Department must base this approval on a site-specific study a system conducts that follows a Department-approved protocol.
(d) Ultraviolet Light.
(i) UV Dose Table.
The treatment credits listed in this table are for UV light at a wavelength of 254 nanometers 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 R.61-58.10.K(21)(d)(ii). 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) |
| 0.5 | 1.6 | 1.5 | 39 |
| 1.0 | 2.5 | 2.1 | 58 |
| 1.5 | 3.9 | 3.0 | 79 |
| 2.0 | 5.8 | 5.2 | 100 |
| 2.5 | 8.5 | 7.7 | 121 |
| 3.0 | 12 | 11 | 143 |
| 3.5 | 15 | 15 | 163 |
| 4.0 | 22 | 22 | 186 |
(ii) Reactor Validation Testing.
(C) The Department may approve an alternative approach to validation testing.
(iii) Reactor Monitoring.
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 R.61-58.10.K(21)(d)(i) (i.e., validated operating conditions). These operating conditions must include flow rate, UV intensity as measured by a UV sensor, and UV lamp status.
Systems may receive Cryptosporidium, Giardia lamblia, and virus treatment credits for ultraviolet (UV) light reactors by achieving the corresponding UV dose values shown in R.61-58.10.K(21)(d)(i). Systems must validate and monitor UV reactors as described in R.61-58.10.K(21)(d)(ii) and (iii) to demonstrate that they are achieving a particular UV dose value for treatment credit.
(22) Reporting Requirements.
(f) Systems must report to the Department in accordance with R.61-58.10.K(22)(f)(i) through (xv) for any microbial toolbox options used to comply with treatment requirements under R.61-58.10.K(12) or (13). Alternatively, the Department may approve a system to certify operation within required parameters for treatment credit rather than reporting monthly operational data for toolbox options.
(i) Watershed Control Program
Systems must submit the following information:
(ii) Alternative source or intake management: Systems must submit verification that the system has relocated the intake or adopted the intake withdrawal procedure reflected in the monitoring results. The verification must be sent no later than the applicable compliance date in R.61-58.10.K(14).
(iii) Presedimentation: A monthly report must be submitted within 10 days following the month in which the monitoring was conducted that contains verification of continuous basin operation, treatment of 100 percent of the flow, continuous addition of a coagulant, and at least 0.5-log mean reduction of influent turbidity or compliance with alternative Department-approved performance criteria beginning on the applicable treatment compliance date in R.61-58.K(14).
(v) Bank Filtration:
(vi) Combined filter performance: Systems must submit monthly verification of their combined filter effluent levels within 10 days following the month in which the monitoring was conducted beginning on the applicable treatment compliance date in R.61-58.10.K(14). The report must verify that the combined filter effluent turbidity levels were less than or equal to 0.15 NTU in at least 95 percent of the 4 hour combined filter effluent measurements taken each month.
(vii) Individual filter performance: Systems must submit a report within 10 days following the month in which the monitoring was conducted beginning on the applicable treatment compliance date in R.61-58.10.K(14). The report must verify that the individual filter effluent turbidity levels were less than or equal to 0.15 in at least 95 percent of samples each month in each filter, and that no individual filter turbidity was greater than 0.3 NTU in two consecutive readings 15 minutes apart.
(viii) Demonstration of Performance.
(ix) Bag Filters and Cartridge Filters:
(x) Membrane Filtration:
(xi) Second stage filtration: Systems must submit monthly verification that 100 percent of the flow was filtered through both stages and that the first stage was preceded by coagulation. This verification must be submitted within 10 days following the month that monitoring was conducted, beginning on the applicable treatment compliance date in R.61-58.10.K(14).
(xii) Slow sand filtration (as secondary filter): Systems must submit monthly verification that both a slow sand filter and a preceding separate stage of filtration treated 100 percent of the flow from a subpart H source. This verification must be submitted within 10 days following the month that monitoring was conducted, beginning on the applicable treatment compliance date in R.61-58.10.K(14).
(xiii) Chlorine dioxide: Systems must submit a summary of CT values for each day as described in R.61-58.10.K(21). This summary must be submitted within 10 days following the month that monitoring was conducted, beginning on the applicable treatment compliance date in R.61-58.10.K(14).
(xiv) Ozone: Systems must submit a summary of CT values for each day as described in R.61-58.10.K(21). This summary must be submitted within 10 days following the month that monitoring was conducted, beginning on the applicable treatment compliance date in R.61-58.10.K(14).
(xv) UV:
(23) Recordkeeping Requirements.
(24) Requirements to Respond to Significant Deficiencies Identified in Sanitary Surveys Performed by EPA.
HISTORY: Amended by State Register Volume 19, Issue No. 7, eff July 28, 1995; State Register Volume 24, Issue No. 2, eff February 25, 2000; State Register Volume 25, Issue No. 9, eff September 28, 2001; State Register Volume 26, Issue No. 12, eff December 27, 2002; State Register Volume 28, Issue No. 1, eff January 23, 2004; State Register Volume 30, Issue No. 10, eff October 27, 2006; State Register Volume 32, Issue No. 4, eff April 25, 2008; State Register Volume 38, Issue No. 9, Doc. No. 4469, eff September 26, 2014.