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 History
History: CR 09-073: cr.
Register November 2010 No. 659, eff. 12-1-10.
NR 810.32
NR 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 CT
99.9 (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.
NR 810.32(2)(b)2.
2. For systems using chlorine, the pH of the disinfected water shall be measured at each chlorine residual disinfectant concentration sampling point during peak hourly flow.
NR 810.32(2)(b)3.
3. The disinfectant contact times (“T") shall be determined during peak hourly flow.
NR 810.32(2)(b)4.
4. The residual disinfectant concentrations (“C") of the water before or at the first customer and prior to each additional point of disinfection shall be measured during peak hourly flow.
NR 810.32(2)(c)
(c) In lieu of conducting new monitoring under
par. (b), public water systems may elect to meet the following requirements:
NR 810.32(2)(c)1.
1. Water suppliers for systems that have at least one year of existing data that are substantially equivalent to data collected under
par. (b) may use these data to develop disinfection profiles as specified in this section if the water system has neither made a significant change to its treatment practice nor changed sources since the data were collected. Water suppliers may develop disinfection profiles using up to 3 years of existing data.
NR 810.32(2)(c)2.
2. Water suppliers may use disinfection profile or profiles developed previously in lieu of developing a new profile if the water system has not made a significant change, as determined under
sub. (1) (b), to its treatment practice or has not changed sources since the profile was developed. Water suppliers for systems that have not developed a virus profile shall develop a virus profile using the same monitoring data on which the
Giardia lamblia profile is based.
NR 810.32(2)(d)
(d) The water supplier shall calculate the total inactivation ratio for
Giardia lamblia as follows:
NR 810.32(2)(d)1.
1. For water systems using only one point of disinfectant application, the water supplier may determine the total inactivation ratio for the disinfection segment based on either of the following methods:
NR 810.32(2)(d)1.a.
a. Determine one inactivation ratio (CT
calc/CT
99.9) before or at the first customer during peak hourly flow.
NR 810.32(2)(d)1.b.
b. Determine successive (CT
calc/CT
99.9) 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, the water supplier shall calculate the total inactivation ratio by determining (CT
calc/CT
99.9) for each sequence and then adding the (CT
calc/CT
99.9) values together to determine (
S (CT
calc/CT
99.9)).
NR 810.32(2)(d)2.
2. For systems using more than one point of disinfectant application before the first customer the water supplier shall 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 (CT
calc/CT
99.9) value of each segment and (
S (CT
calc/CT
99.9)) shall be calculated using the method in
subd. 1.
NR 810.32(2)(d)3.
3. The water supplier shall determine the total logs of inactivation by multiplying the value calculated in
subd. 1. or
2. by 3.0.
NR 810.32(2)(e)
(e) Water suppliers shall determine the total logs of inactivation for viruses using a protocol approved by the department.
NR 810.32(2)(f)
(f) For water systems required to calculate a disinfection benchmark water suppliers shall use the following procedure:
NR 810.32(2)(f)1.
1. For each year of profiling data collected and calculated under this subsection, the water supplier shall determine the lowest mean monthly level of both
Giardia lamblia and virus inactivation. The water supplier shall determine the mean
Giardia lamblia and virus inactivation for each calendar month for each year of profiling data by dividing the sum of daily or weekly
Giardia lamblia and virus log inactivation by the number of values calculated for that month.
NR 810.32(2)(f)2.
2. The disinfection benchmark is the lowest monthly mean value, for water systems with one year of profiling data, or the mean of lowest monthly mean values, for water systems with more than one year of profiling data, of the monthly logs of
Giardia lamblia and virus log inactivation in each year of profiling data.
NR 810.32 History
History: CR 09-073: cr.
Register November 2010 No. 659, eff. 12-1-10.
NR 810.33
NR 810.33 Enhanced treatment requirements for Cryptosporidium. NR 810.33(1)
(1)
Applicability. The requirements of this section apply to all public water systems supplied by a surface water source and public water systems supplied by a groundwater source under the direct influence of surface water.
NR 810.33(1)(a)
(a) Wholesale systems shall comply with the requirements of this section based on the population of the largest system in the combined distribution system.
NR 810.33(1)(b)
(b) The requirements of this section for filtered systems apply to water systems required by
s. NR 810.29 to provide filtration treatment, whether or not the system is currently operating a filtration system.
NR 810.33(1)(c)
(c) The requirements of this section for unfiltered groundwater systems under the direct influence of surface water apply only to unfiltered systems that timely met and continue to meet the filtration avoidance criteria in
s. NR 810.30.
NR 810.33(2)
(2) Requirements. Public water systems shall comply with the following requirements:
NR 810.33(2)(a)
(a) Water suppliers shall conduct an initial and a second round of source water monitoring for each plant that treats a surface water or GWUDI source. This monitoring may include sampling for
Cryptosporidium, E. coli, and turbidity as described in
s. NR 809.331, to determine what level, if any, of additional
Cryptosporidium treatment they shall provide.
NR 810.33(2)(b)
(b) Water suppliers for systems that plan to make a significant change to their disinfection practice shall develop disinfection profiles and calculate disinfection benchmarks, as described in
s. NR 810.32.
NR 810.33(2)(c)
(c) Water suppliers for filtered systems shall determine their
Cryptosporidium treatment bin classification as described in
s. NR 810.34 and provide additional treatment for
Cryptosporidium, if required, as described in
s. NR 810.35. All unfiltered GWUDI systems shall provide treatment for
Cryptosporidium as described in
s. NR 810.36. Filtered systems and unfiltered GWUDI systems shall implement
Cryptosporidium treatment according to the schedule in
s. NR 810.37.
NR 810.33(2)(d)
(d) Water systems with uncovered finished water storage facilities shall comply with the requirements to cover the facility as described in
s. NR 810.28. Finished water is that water which has received all required treatment.
NR 810.33(2)(e)
(e) Water systems required to provide additional treatment for
Cryptosporidium shall implement microbial toolbox options that are designed and operated as described in
ss. NR 810.41 to
810.46.
NR 810.33(2)(f)
(f) Water suppliers for water systems shall comply with the applicable recordkeeping and reporting requirements described in
ss. NR 810.39 and
810.40.
NR 810.33 History
History: CR 09-073: cr.
Register November 2010 No. 659, eff. 12-1-10.
NR 810.34
NR 810.34 Cryptosporidium bin classification for filtered systems. NR 810.34(1)(1) Following completion of the initial round of source water monitoring required under
s. NR 809.331 (1), water suppliers for filtered systems shall calculate an initial
Cryptosporidium bin concentration for each plant for which monitoring was required. Calculation of the bin concentration shall use the
Cryptosporidium results reported under
s. NR 809.331 (1) and shall follow the procedures in
sub. (2) (a) to
(e).
NR 810.34(2)(a)(a) For filtered systems that collect a total of at least 48 samples, the bin concentration is equal to the arithmetic mean of all sample concentrations.
NR 810.34(2)(b)
(b) For filtered 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.
NR 810.34(2)(c)
(c) For filtered systems that serve fewer than 10,000 people and monitor for
Cryptosporidium for only one year, collecting 24 samples in 12 months, the bin concentration is equal to the arithmetic mean of all sample concentrations.
NR 810.34(2)(d)
(d) For filtered systems with plants operating only part of the year that monitor fewer than 12 months per year under
s. NR 809.331 (5), the bin concentration is equal to the highest arithmetic mean of all sample concentrations during any year of
Cryptosporidium monitoring.
NR 810.34(2)(e)
(e) If the monthly
Cryptosporidium sampling frequency varies, water suppliers shall first calculate a monthly average for each month of monitoring. Systems shall then use these monthly average concentrations, rather than individual sample concentrations, in the applicable calculation for bin classification in
pars. (a) to
(d).
NR 810.34(3)
(3) Water suppliers for filtered systems shall determine their initial bin classification from the following table and using the
Cryptosporidium bin concentration calculated under
subs. (1) and
(2):
1Based on calculations in sub. (1) or (4), as applicable.
NR 810.34(4)
(4) Following completion of the second round of source water monitoring required under
s. NR 809.331 (2), water suppliers for filtered systems shall recalculate their
Cryptosporidium bin concentration using the
Cryptosporidium results reported under
s. NR 809.331 (2) and following the procedures in
sub. (2) (a) to
(d). Systems shall then redetermine their bin classification using this bin concentration and the table in
sub. (3).
NR 810.34(5)
(5) Water suppliers shall report their bin classification of the water system as follows:
NR 810.34(5)(a)
(a) Water suppliers for filtered systems shall report the initial bin classification under
par. (c) to the department for approval no later than 6 months after the system is required to complete initial source water monitoring based on the schedule in
s. NR 809.331 (3).
NR 810.34(5)(b)
(b) Water suppliers for filtered systems shall report the bin classification under
sub. (4) 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
s. NR 809.331 (3).
NR 810.34(5)(c)
(c) The bin classification report to the department shall include a summary of source water monitoring data and the calculation procedure used to determine bin classification.
NR 810.34(6)
(6) Failure to comply with the conditions of
sub. (5) is a violation of the treatment technique requirement.
