Chapter NR 810

NR 810.26(8)(b) (b) Procedures for adding chlorine to the water system, flushing the water system to move chlorine to extremities, and testing chlorine levels.

NR 810.26(8)(c) (c) Example calculations for determining dosage requirements.

NR 810.26 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; correction in (6) made under s. 13.92 (4) (b) 7., Stats., Register November 2010 No. 659.

subch. II of ch. NR 810 Subchapter II — Surface Water Treatment and Groundwater Under the Direct Influence of Surface Water Treatment Operations

NR 810.27 NR 810.27 General requirements for all surface water and groundwater under the direct influence of surface water systems.

NR 810.27(1) (1) This subchapter establishes criteria under which filtration is required as a treatment technique for public water systems supplied by a surface water source or a groundwater source under the direct influence of surface water. Direct influence shall be determined for individual sources by the department. The department determination of direct influence may be based on site-specific measurements of water quality characteristics such as those stated in s. NR 810.02 (25) or documentation of well construction characteristics and geology with field evaluation. These regulations also establish requirements for treatment techniques in lieu of maximum contaminant levels for Giardia lamblia, viruses, heterotrophic plate count bacteria, Legionella, Cryptosporidium and turbidity. Treatment technique requirements apply to every public water system which utilizes surface water or groundwater under the direct influence of surface water and the requirements consist of installing and properly operating water treatment processes which reliably achieve:

NR 810.27(1)(a) (a) At least 99.9% or 3-log removal or inactivation of Giardia lamblia cysts between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer.

NR 810.27(1)(b) (b) At least 99.99% or 4-log removal or inactivation of viruses between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer.

NR 810.27(1)(c) (c) At least 99.9% or 3-log removal of Cryptosporidium between a point where the raw water is not subject to recontamination by surface water runoff and a point downstream before or at the first customer for filtered systems, or Cryptosporidium control under the watershed control system for unfiltered GWUDI systems.

NR 810.27(2) (2) A public water system using a surface water source is considered to be in compliance with the requirements of sub. (1) if it meets the filtration requirements in s. NR 810.29 and the disinfection requirements in s. NR 810.31.

NR 810.27(3) (3) A public water system using groundwater under the direct influence of surface water is considered to be in compliance with the requirements or sub. (1) if it meets the criteria for avoiding filtration in s. NR 810.30 along with the disinfection requirements in s. NR 810.31; or if it meets the filtration requirements in s. NR 810.29 and it meets the disinfection requirements in s. NR 810.31.

NR 810.27(4) (4) Each public water system using a surface water source or a groundwater under the direct influence of surface water shall be operated by qualified personnel who meet the requirements specified by the department.

NR 810.27 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 810.28 NR 810.28 Requirements for covers on water storage structures. All finished water storage reservoirs and treatment plant basins shall be covered. Finished water is that water which has received all required treatment. Treatment plant basins contain water at various stages of treatment.

NR 810.28 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 810.29 NR 810.29 Basic filtration requirements. Public water systems that use a surface water source shall provide filtration which complies with the requirements of sub. (1), (2), (3), (4), or (5) and meets the disinfection criteria specified in s. NR 810.31 (2). Public water systems that use a groundwater source under the direct influence of surface water shall provide filtration which complies with the specifications of sub. (1), (2), (3), (4) or (5) and meets the disinfection criteria specified in s. NR 810.31 (2) within 18 months of the date that a source is determined, by the department, to be under the direct influence of surface water unless they meet the filtration avoidance criteria in s. NR 810.30. Failure to meet the applicable requirements of this section is a treatment technique violation.

NR 810.29(1) (1) Conventional filtration treatment.

NR 810.29(1)(a) (a) For systems using conventional filtration treatment, the turbidity level of representative samples of a system’s filtered water shall be less than or equal to 0.3 nephelometric turbidity units (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(1)(b) (b) The turbidity level of representative samples of a system’s filtered water may not exceed one NTU, measured as specified in s. NR 809.113 (1) Tables A and B.

NR 810.29(1)(c) (c) To determine compliance with par. (a), turbidity measurements shall be performed on representative samples of filtered water at least every 4 hours that the system serves water to the public.

NR 810.29(1)(d) (d) In lieu of the requirements of par. (c), turbidity measurements from a continuous reading and recording turbidity monitoring device shall be recorded at predetermined 4-hour intervals to determine compliance with par. (a). The highest turbidity measurement recorded at any time during the day shall be reported under s. NR 809.80 (7) (a) 1.

NR 810.29(1)(e) (e) A system that uses lime softening may acidify representative samples prior to analysis if using a protocol approved by the department.

NR 810.29(2) (2) Direct filtration.

NR 810.29(2)(a) (a) For systems using direct filtration, the turbidity level of representative samples of a system’s filtered water shall be less than or equal to 0.3 NTU in at least 95% of the measurements taken each month, measured as specified in s. NR 809.113 (1), Tables A and B. The department may approve a turbidity limit up to one NTU if the water supplier provides the department with documentation which reliably indicates the system achieves at least 99.9% removal or inactivation of Giardia lamblia cysts at a turbidity level above 0.5 NTU at least 95% of the time that the system delivers water to the public.

NR 810.29(2)(b) (b) The turbidity level of representative samples of a system’s filtered water may not exceed 1 NTU, measured as specified in s. NR 809.113 (1), Tables A and B.

NR 810.29(3) (3) Slow sand filtration.

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) (4) Diatomaceous earth filtration.

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 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 810.295 NR 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 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 810.30 NR 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) (1) Source water quality conditions.

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) (2) Site-specific conditions.

NR 810.30(2)(a) (a)

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)2. 2. The public water system shall meet the requirements of s. NR 810.31 (1) (b) at all times the system serves water to the public.

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)1. 1. A review of the effectiveness of the watershed control program.

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)5. 5. A review of operating procedures.

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) (3) Treatment technique violations.

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 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 810.31 NR 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) (d)

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) (c)