NR 810.29(3)(a)(a) For systems using slow sand filtration, the turbidity level of representative samples of a system’s filtered water shall be less than or equal to 1 NTU in at least 95% of the measurements taken each month, measured as specified in s. NR 809.113 (1), Tables A and B. NR 810.29(3)(b)(b) The turbidity level of representative samples of a system’s filtered water may not exceed 5 NTU, measured as specified in s. NR 809.113 (1), Tables A and B. NR 810.29(4)(a)(a) For systems using diatomaceous earth filtration, the turbidity level of representative samples of a system’s filtered water shall be less than or equal to one NTU in at least 95% of the measurements taken each month, measured as specified in s. NR 809.113 (1), Tables A and B. NR 810.29(4)(b)(b) The turbidity level of representative samples of a system’s filtered water may not exceed 5 NTU, measured as specified in s. NR 809.113 (1), Tables A and B. NR 810.29(5)(5) Other filtration technologies. A public water system may use a filtration technology not listed in subs. (1) to (4) if the water supplier for the system demonstrates to the department, using pilot studies or other means, that the alternative filtration technology, in combination with disinfection treatment that meets the requirements of s. NR 810.31, consistently achieves 99.9% removal or inactivation of Giardia lamblia cysts and 99.99% removal or inactivation of viruses, and 99.9% removal of Cryptosporidium oocysts, and the department approves the use of the filtration technology. For each approval, the department shall set turbidity performance requirements that the water system shall meet at least 95% of the time at a level that consistently achieves 99.9% removal or inactivation of Giardia lamblia cysts, 99.99% removal or inactivation of viruses, and 99% removal of Cryptosporidium oocysts. The department may set other performance requirements to assure the integrity of the technology. NR 810.29 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10. NR 810.295NR 810.295 Filter backwash handling. Public water systems that use a surface water source or groundwater under the direct influence of surface water and that provide filtration shall meet the requirements of s. NR 811.860. NR 810.295 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10. NR 810.30NR 810.30 Criteria for avoiding filtration for groundwater under the direct influence of surface water systems. A public water system that uses groundwater under the direct influence of surface water as a water supply source shall meet all of the conditions of subs. (1) and (2), and is subject to sub. (3), unless the department has determined, in writing, that filtration is required. If the department determines in writing that filtration is required, the water system owner shall install filtration and shall meet the criteria for filtered systems specified in ss. NR 810.29 and 810.31 (2). Within 18 months of the failure of a public water system using a groundwater source under the direct influence of surface water to meet any one of the requirements of subs. (1) and (2), the water system owner shall install filtration and shall meet the criteria for filtered systems specified in ss. NR 810.29 and 810.31 (2). NR 810.30(1)(a)(a) The fecal coliform concentration shall be equal to or less than 20/100ml, or the total coliform concentration shall be equal to or less than 100/100 ml, measured as specified in s. NR 809.311 (1) Table F, in representative samples of the source water immediately prior to the first or only point of disinfectant application in at least 90% of the measurements made for the 6 previous months that the system served water to the public on an ongoing basis. If a system measures both fecal and total coliforms, the fecal coliform criterion, but not the total coliform criterion, in this paragraph shall be met. NR 810.30(1)(b)(b) The turbidity level may not exceed 5 NTU, measured as specified in s. NR 809.113 (1) Tables A and B, in representative samples of the source water immediately prior to the first or only point of disinfectant application unless both of the following apply: NR 810.30(1)(b)1.1. The department determines that a turbidity “event” was caused by circumstances that were unusual and unpredictable. A turbidity “event” is a series of consecutive days during which at least one turbidity measurement each day exceeds 5 NTU. NR 810.30(1)(b)2.2. There have not been more than 2 turbidity events in the past 12 months the water system served water to the public, or more than 5 turbidity events in the past 120 months the system served water to the public. NR 810.30(2)(a)1.1. The public water system shall meet the disinfection requirements of s. NR 810.31 (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. NR 810.30(2)(a)3.3. The public water system shall meet the requirements of s. NR 810.31 (1) (c) at all times the system serves water to the public unless the department determines that any failure was caused by circumstances that were unusual and unpredictable. NR 810.30(2)(a)4.4. The public water system shall meet the requirements of s. NR 810.31 (1) (d) on an ongoing basis unless the department determines that failure to meet these requirements was not caused by a deficiency in treatment of the source water. NR 810.30(2)(b)(b) The public water system shall maintain a department approved wellhead protection program which minimizes the potential for contamination by Cryptosporidium, Giardia lamblia cysts and viruses in the source water. The department shall determine whether the well head protection program is adequate to meet this goal. At a minimum, the program shall do all of the following: NR 810.30(2)(b)1.1. Characterize the watershed hydrology, hydrogeology, and land ownership. NR 810.30(2)(b)2.2. Identify watershed characteristics and activities which may have an adverse effect on source water quality. NR 810.30(2)(b)3.3. Monitor the occurrence of activities which may have an adverse effect on source water quality. NR 810.30(2)(c)(c) The public water system is subject to an annual on-site inspection to assess the well head protection 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 and shall include all of the following: NR 810.30(2)(c)2.2. A review of the physical condition of the source intake and how well it is protected. NR 810.30(2)(c)3.3. A review of the system’s equipment maintenance program to ensure there is low probability for failure of the disinfection process. NR 810.30(2)(c)4.4. An inspection of the disinfection equipment for physical deterioration. NR 810.30(2)(c)6.6. A review of data records to ensure that all required tests are being conducted and recorded and disinfection is effectively practiced. NR 810.30(2)(c)7.7. Identification of any improvements which are needed in the equipment, system maintenance and operation, or data collection. NR 810.30(2)(c)8.8. A review of the adequacy of the watershed control program to limit potential contamination by Cryptosporidium including: 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 or controlled land use, or both, within the watershed. NR 810.30(2)(d)(d) The public water system may not have been identified as a source of a waterborne disease outbreak, or if it has been so identified, the system shall be modified sufficiently to prevent another occurrence, as determined by the department. NR 810.30(2)(e)(e) The public water system shall comply with the maximum contaminant level (MCL) for total coliforms in s. NR 809.30 at least 11 months of the previous 12 months that the system served water to the public, on an ongoing basis, unless the department determines that failure to meet this requirement was not caused by a deficiency in treatment of the source water. NR 810.30(2)(f)(f) The public water system shall comply with the requirements for total trihalomethanes, five haloacetic acids, bromate, chlorite, chlorine, chloramines and chlorine dioxide in s. NR 809.561. NR 810.30(3)(a)(a) A public water system that fails to meet any one of the criteria in subs. (1) and (2), and for which the department has determined in writing that filtration is required, is in violation of a treatment technique requirement. NR 810.30(3)(b)(b) A public water system that has not installed filtration is in violation of a treatment technique if either of the following apply: NR 810.30(3)(b)1.1. The turbidity level in a representative sample of the source water immediately prior to the first or only point of disinfection application exceeds 5 NTU. NR 810.30(3)(b)2.2. The system is identified as a source of a waterborne disease outbreak. NR 810.30(4)(4) Additional circumstances when filtration would be required. The department may require a public water system to install filtration even when the system meets the requirements of subs. (1) and (2) if other water quality characteristics or site specific conditions present a threat to public health which could not be eliminated by disinfection alone. NR 810.30 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10. NR 810.31NR 810.31 Disinfection requirements for Giardia lamblia and viruses. A public water system that uses groundwater under the direct influence of surface water and does not provide filtration shall provide disinfection treatment specified in sub. (1) within 18 months after the department determines that the groundwater source is under the influence of surface water. A system that filters and uses surface water or groundwater under the direct influence of surface water as a source shall provide the disinfection treatment specified in sub. (2) when filtration is installed. Failure to meet any requirement of this section is a treatment technique violation. NR 810.31(1)(1) Disinfection requirements for public water systems using groundwater under the direct influence of surface water that do not provide filtration. NR 810.31(1)(a)(a) The disinfection treatment shall be sufficient to ensure at least 99.9% (3 log) inactivation of Giardia lamblia cysts and 99.99% (4 log) inactivation of viruses, every day the system serves water to the public. Each day a system serves water to the public, the water supplier shall calculate the CT value from the system’s treatment parameters using the procedure specified in s. NR 810.38 (1) (d), and determine whether this value is sufficient to achieve the specified inactivation rates for Giardia lamblia cysts and viruses. Water suppliers for systems using a disinfectant other than chlorine shall demonstrate to the department through on-site challenge studies or other information that the system is achieving required minimum inactivation rates. NR 810.31(1)(b)(b) The disinfection system shall have either redundant components, including an auxiliary power supply with automatic start-up and alarm to ensure that disinfectant application is maintained continuously while water is being delivered to the distribution system, or automatic shut-off of water delivery to the distribution system whenever there is less than 0.2 mg/l of residual disinfectant concentration in the water. If the department determines that automatic shut-off of delivery of water to the distribution system would cause an unreasonable risk to health or property, the disinfection system shall have redundant components. NR 810.31(1)(c)(c) The residual disinfectant concentration in the water entering the distribution system, measured as specified in s. NR 809.563 (2), Table R, may not be less than 0.2 mg/l for more than 4 hours. NR 810.31(1)(d)1.1. The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine, or chlorine dioxide, as specified in s. NR 809.563 (2), Table R, may not be undetectable in more than 5% of the samples each month, for any 2 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 s. NR 809.311 (1), Table F, 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% in one month for any 2 consecutive months. V = c + d + e/a + b x 100
where:
a = number of instances where the residual disinfectant con centration 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.
e = number of instances where the residual disinfectant concentration is not measured and HPC is > 500/ml.
NR 810.31(1)(d)2.2. If the department determines, based on site specific considerations, that a public water system has no means for having a sample transported and analyzed for HPC by a certified laboratory under the requisite time and temperature conditions required in s. NR 809.311 (1), Table F, and that the system is providing adequate disinfection in the distribution system, the requirements of subd. 1. do not apply. NR 810.31(2)(2) Disinfection requirements for public water systems which provide filtration. Each public water system that provides filtration treatment shall provide disinfection treatment as follows: NR 810.31(2)(a)(a) Disinfection treatment shall be sufficient to ensure that the total treatment processes of that system achieve at least 99.9% (3 log) inactivation or removal of Giardia lamblia cysts and at least 99.99% (4 log) inactivation or removal of viruses, as determined by the department. NR 810.31(2)(b)(b) The residual disinfectant concentration in the water entering the distribution system, measured as specified in s. NR 809.563 (2), Table R, may not be less than 0.2 mg/l for more than 4 hours. NR 810.31(2)(c)1.1. The residual disinfectant concentration in the distribution system, measured as total chlorine, combined chlorine or chlorine dioxide, as specified in s. NR 809.563 (2), Table R, may not be undetectable in more than 5% of the samples each month, for any 2 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 s. NR 809.311 (1), Table F, is deemed to have a detectable disinfectant residual for purposes of determining compliance with this requirement. Thus, the value “V” in the following formula may not exceed 5% in one month, for any 2 consecutive months. V = c + d + e/a + b x 100
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.
e = number of instances where the residual disinfectant concentration is not measured and HPC is > 500/ml.
NR 810.31(2)(c)2.2. If the department determines, based on site specific considerations, that a public water system has no means for having a sample transported and analyzed for HPC by a certified laboratory under the requisite time and temperature conditions required in s. NR 809.311 (1), Table F, and that the system is providing adequate disinfection in the distribution system, the requirements of subd. 1. do not apply. NR 810.31 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10. NR 810.32NR 810.32 Disinfection profiling and benchmarking. NR 810.32(1)(1) Requirements when making a significant change in disinfection practice. NR 810.32(1)(a)(a) Following the completion of initial source water monitoring under s. NR 809.331, the water supplier for a public water system that plans to make a significant change to its disinfection practice, as defined in par. (b), shall develop disinfection profiles and calculate disinfection benchmarks for Giardia lamblia and viruses as described in sub. (2). Prior to changing the disinfection practice, the water supplier shall notify the department and shall include in this notice all of the following information: NR 810.32(1)(a)1.1. A completed disinfection profile and disinfection benchmark for Giardia lamblia and viruses as described in sub. (2). NR 810.32(1)(a)3.3. An analysis of how the proposed change will affect the current level of disinfection. NR 810.32(1)(b)(b) Significant changes to disinfection practice are defined as any of the following: NR 810.32(1)(b)4.4. Any other modification identified by the department as a significant change to disinfection practice. Additional barriers with no change to existing disinfection practices may be exempt from these requirements. NR 810.32(2)(2) Developing the disinfection profile and benchmark. Water suppliers for public water systems required to develop disinfection profiles under sub. (1) shall follow the requirements of this subsection: NR 810.32(2)(a)(a) Water suppliers shall monitor at least weekly for a period of 12 consecutive months to determine the total logs of inactivation for Giardia lamblia and viruses. If water suppliers monitor more frequently, the monitoring frequency shall be evenly spaced. Systems that operate for fewer than 12 months per year shall be monitored weekly during the period of operation. Water suppliers shall determine log inactivation for Giardia lamblia through the entire plant, based on the CT99.9 (3 log) values in ss. NR 810.47 to 810.62. Water suppliers shall determine log inactivation for viruses through the entire treatment plant based on a protocol approved by the department. NR 810.32(2)(b)(b) Water suppliers for systems with a single point of disinfectant application prior to entrance to the distribution system shall conduct the monitoring in subds. 1. to 4. Water suppliers for systems with more than one point of disinfectant application shall conduct the monitoring in subds. 1. to 4. for each disinfection segment. Water suppliers shall monitor the parameters necessary to determine the total inactivation ratio, using analytical methods in s. NR 809.563 (2), Table R. NR 810.32(2)(b)1.1. For systems using a disinfectant other than UV, the temperature of the disinfected water shall be measured at each residual disinfectant concentration sampling point during peak hourly flow.
