NR 809.563(6)(d)2. 2. When determining SUVA, water suppliers shall use the methods stipulated in par. (e) to measure DOC and the method stipulated in par. (f) to measure UV254 SUVA shall be determined on water prior to the addition of disinfectants or oxidants, or both, by the water supplier.

NR 809.563(6)(d)3. 3. DOC and UV254 samples used to determine a SUVA value shall be taken at the same time and at the same location.

NR 809.563(6)(e) (e) Dissolved organic carbon (DOC). For measuring dissolved organic carbon, use Standard Method 5310 B (High-Temperature Combustion Method) or Standard Method 5310 C (Persulfate-Ultraviolet or Heated-Persulfate Oxidation Method) or Standard Method 5310 D (Wet-Oxidation Method). Prior to analysis, DOC samples shall be filtered through a 0.45 mm pore-diameter filter. Water passed through the filter prior to filtration of the sample shall serve as the filtered blank. This filtered blank shall be analyzed using procedures identical to those used for analysis of the samples and shall meet the following criteria: DOC < 0.5 mg/L. DOC samples shall be filtered through the 0.45 mm pore-diameter filter prior to acidification. DOC samples shall either be analyzed or shall be acidified to achieve pH less than 2.0 by minimal addition of phosphoric or sulfuric acid as soon as practical after sampling, not to exceed 48 hours. Acidified DOC samples shall be analyzed within 28 days.

NR 809.563(6)(f) (f) Ultraviolet absorption at 254 nm (UV254). For measuring ultraviolet absorption at 254 nm, use Method 5910 B (Ultraviolet Absorption Method). UV absorption shall be measured at 253.7 nm (may be rounded off to 254 nm). Prior to analysis, UV254 samples shall be filtered through a 0.45 mm pore-diameter filter. The pH of UV254 samples may not be adjusted. Samples shall be analyzed as soon as practical after sampling, not to exceed 48 hours.

NR 809.563(6)(g) (g) pH. For measuring pH, use any method allowed in s. NR 809.113 (1) Table A.

NR 809.563(6)(h) (h) Magnesium. All methods allowed in s. NR 809.113 (1) Table A.

NR 809.563 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 15-049: am. (1), (2), r. and recr. (2) Table R, (3) Table S, am. (4) (a), (b), r. (4) (d), am. (4) (e), Table U, (5), (6) (intro.), cr. (6) (h) Register March 2016 No. 723, eff. 4-1-16.

NR 809.565 NR 809.565 Monitoring requirements for disinfection byproducts and disinfection residuals Stage 1 DBP.

NR 809.565(1) (1) General requirements. General requirements under this subchapter for analytical requirements, determining maximum contaminant levels, conducting monitoring and control of disinfection byproducts are as follows:

NR 809.565(1)(a) (a) Water suppliers shall take all samples during normal operating conditions.

NR 809.565(1)(b) (b) Water suppliers may consider multiple wells drawing water from a single aquifer as one treatment plant for determining the minimum number of TTHM and HAA5 samples required, on a case-by-case basis with department approval.

NR 809.565(1)(c) (c) Failure to monitor in accordance with the monitoring plan required under sub. (6) is a monitoring violation.

NR 809.565(1)(d) (d) Failure to monitor shall be treated as a violation for the entire period covered by the annual average where compliance is based on a running annual average of monthly or quarterly samples or averages and the water supplier’s failure to monitor makes it impossible to determine compliance with MCLs or MRDLs.

NR 809.565(1)(e) (e) Water suppliers may use only data collected under the provisions of this subchapter

NR 809.565(2) (2) Monitoring frequency and location for TTHMs and HAA5s. Water suppliers shall monitor at the following frequency and locations for TTHMs and HAA5 disinfection byproducts:

NR 809.565(2)(a) (a) Routine monitoring.

NR 809.565(2)(a)1. 1. Water suppliers for public water systems serving at least 10,000 persons which are supplied by a surface water source or by a groundwater source under the direct influence of surface water shall collect and have analyzed 4 water samples per quarter per treatment plant.

NR 809.565(2)(a)1.a. a. At least 25% of all samples collected each quarter at each treatment plant shall be at locations representing the maximum residence time in the public water system.

NR 809.565(2)(a)1.b. b. The remaining samples shall be taken in the distribution system at locations representing at least average residence time in the public water system and representative of the entire distribution system, taking into account the number of people served, different sources of water and different treatment methods.

NR 809.565(2)(a)2. 2. Water suppliers for public water systems serving from 500 to 9,999 persons which are supplied by a surface water source or by a groundwater source under the direct influence of surface water shall collect and have analyzed one water sample per quarter per treatment plant. The samples shall be collected at locations representing the maximum residence time of water in the public water system.

NR 809.565(2)(a)3. 3. Water suppliers for public water systems serving fewer than 500 people which are supplied by a surface water source or by a groundwater source under the direct influence of surface water shall collect one sample per treatment plant annually. The samples shall be collected during the month with the warmest water temperature at locations representing the maximum residence time in the public water system.

NR 809.565(2)(a)4. 4. Water suppliers for public water systems using chemical disinfection, using only groundwater not under the direct influence of surface water, and serving at least 10,000 people shall collect one sample per treatment plant per quarter. The sample or samples shall be collected at the location representing the maximum residence time in the public water system.

NR 809.565(2)(a)5. 5. Water suppliers for public water systems using chemical disinfection, using only groundwater not under the direct influence of surface water, and serving fewer than 10,000 people shall collect one sample per treatment plant annually. The sample shall be collected during the month with the warmest water temperature, at locations representing the maximum residence time, in the public water system.

NR 809.565(2)(b) (b) Monitoring after exceeding an MCL. If a sample or the average of samples, if more than one sample is taken, exceeds the MCL for TTHMs or HAA5 disinfection byproducts, the water supplier shall collect quarterly samples until the public water system meets the requirements of reduced monitoring in par. (c).

NR 809.565(2)(c) (c) Reduced monitoring. Water suppliers may reduce monitoring for TTHMs and HAA5s as follows:

NR 809.565(2)(c)1. 1. Water suppliers for surface water systems or groundwater systems under the direct influence of surface water with an annual average of TTHM of < 0.040 mg/L and HAA5 =0.030 mg/L with an annual average TOC concentration of < 4.0 mg/L, before any treatment may reduce monitoring to the following:

NR 809.565(2)(c)1.a. a. Water suppliers for a public water system serving at least 10,000 people may reduce monitoring to one sample per quarter per treatment plant so long as the sample is taken at a location representing maximum residence time in the public water system.

NR 809.565(2)(c)1.b. b. Water suppliers for a public water system serving from 500 to 9,999 people may reduce monitoring to one sample per year per treatment plant so long as the sample is taken at a location representing maximum residence time in the public water system during the month of warmest water temperature.

NR 809.565(2)(c)1.c. c. A water supplier for a public water system serving less than 500 people may not reduce monitoring to less than one sample during the month of warmest water temperature per treatment plant per year.