NR 809.115(5)(c)(c) Increased monitoring due to detection at one-half the MCL and greater. The repeat monitoring frequency shall be quarterly for at least one year following any one sample in which the concentration of nitrite is greater than or equal to 0.5 mg/L nitrite as nitrogen. The department may reduce the sampling frequency to annual after determining the concentration is reliably and consistently less than the MCL. Each subsequent annual sample shall be taken during the quarter which previously resulted in the highest analytical result.

NR 809.115(5)(d)(d) Monitoring if an MCL is exceeded. If nitrite sampling results indicate an exceedance of the MCL, the water supplier shall take a confirmation sample as required under sub. (6) (b).

NR 809.115(6)(6) Confirmation samples. The collection of confirmation samples shall comply with the following requirements:

NR 809.115(6)(a)(a) Department required confirmation samples. The department may require the collection of a confirmation sample where sample results indicate an exceedance of the MCL for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium. The confirmation sample shall be collected as soon as possible after the initial sample results were received, but not exceeding 2 weeks, at the same entry point.

NR 809.115(6)(b)(b) Mandatory confirmation samples. If nitrate or nitrite sampling results indicate an exceedance of the MCL, the water supplier shall take a confirmation sample within 24 hours of the water supplier’s receipt of notification of the analytical results of the first sample. Water suppliers unable to comply with the 24-hour sampling requirement shall immediately notify the consumers served by the public water system in accordance with subch. VII and meet other Tier 1 public notification requirements under subch. VII. Water suppliers exercising this option shall take and analyze a confirmation sample within 2 weeks of notification of the analytical results of the first sample.

NR 809.115(6)(c)(c) Averaging of confirmation samples. If a confirmation sample is required for any contaminant, the results of the original and the confirmation sample shall be averaged. The resultant average shall be used to determine the public water system’s compliance in accordance with s. NR 809.117 (1).

NR 809.115(7)(7) Sampling frequency. The department may require more frequent monitoring than specified in subs. (2), (3), (4) and (5) and may require confirmation samples for positive and negative results at its discretion.

NR 809.115(8)(8) Increased monitoring. Water suppliers may apply to the department to conduct more frequent monitoring than the minimum monitoring frequencies specified in this section.

NR 809.115(9)(9) Designated sampling time. Each public water system shall be monitored during the month, quarter or year designated by the department during each compliance period for all monitoring required under subs. (2), (3), (4) and (5).

NR 809.115(10)(10) Sampling errors. The department may delete results of obvious sampling errors, or may require the collection of additional samples to determine whether the result is or is not in error.

NR 809.115 HistoryHistory: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 15-049: am. (1) (d), (2) (f) 2., (3) (intro.), (a), (b) Register March 2016 No. 723, eff. 4-1-16.

NR 809.117(1)(1) Compliance determinations. Compliance for inorganic contaminants shall be determined based on all of the following:

NR 809.117(1)(a)(a) Compliance with s. NR 809.11 shall be determined based on the analytical results obtained at each entry point. Any contaminant listed in s. NR 809.11 which is detected shall be quantified.

NR 809.117(1)(b)(b) For public water systems which are monitored more frequently than annually, compliance with the MCLs for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium is determined by a running annual average at each entry point. If the average at any sampling point is greater than the MCL, then the public water system is out of compliance. If any one or more samples would cause the annual average to exceed an MCL, then the public water system is out of compliance immediately. Any sample below the reported method detection limit shall be calculated at zero for the purpose of determining the annual average. If a water supplier fails to collect the required number of samples, compliance shall be based on the total number of samples collected.

NR 809.117(1)(c)(c) For public water systems which are monitored annually, or less frequently, the public water system is out of compliance with the MCL for antimony, arsenic, asbestos, barium, beryllium, cadmium, chromium, cyanide, fluoride, mercury, nickel, selenium or thallium if the level of a contaminant at any entry point is greater than the MCL. If a confirmation sample is required by the department, compliance shall be based on the average of the 2 samples. If a water supplier fails to collect the required number of samples, compliance shall be based on the total number of samples collected.

NR 809.117(1)(d)(d) Compliance with the MCLs for nitrate, nitrite or combined nitrate and nitrite is determined based on one sample if the levels of these contaminants are below the MCLs. If the levels exceed a MCL in the initial sample, a confirmation sample is required in accordance with s. NR 809.115 (6) (b). Compliance shall be determined based on the average of the initial and confirmation samples.

NR 809.117(1)(f)(f) Public water systems remain out of compliance with the MCLs for nitrate, nitrite, or combined nitrate and nitrite until the results of 4 consecutive quarterly samples do not exceed the MCL. The department may specify alternate means for returning to compliance with the MCLs for nitrate, nitrite, or combined nitrate and nitrite. Alternate compliance agreements shall be in writing.

NR 809.117(2)(2) Monitoring and reporting violations. Failure to monitor shall result in a monitoring and reporting violation.

NR 809.117(3)(3) Use of analytical results. The department may determine compliance or initiate enforcement action based upon analytical results and other information compiled by their sanctioned representatives and agencies.

NR 809.118(1)(1) General. The water supplier for a community water system shall collect and analyze one sample per plant at the entry point to the distribution system for the determination of sodium concentration. Samples shall be collected and analyzed annually for public water systems utilizing surface water sources in whole or in part, and at least every 3 years for public water systems utilizing solely groundwater sources. The minimum number of samples required to be taken by the public water system shall be based on the number of plants used by the public water system, except that multiple wells drawing raw water from a single aquifer may, with department approval, be considered one plant for determining the minimum number of samples. The water supplier may be required by the department to collect and analyze water samples for sodium more frequently in locations where the sodium content is variable.

NR 809.118(2)(2) Department notification. The water supplier shall report to the department the results of the analyses for sodium concentration within the first 10 days of the month following the month in which the sample results were received or within the first 10 days following the end of the required monitoring period as stipulated by the department, whichever is first. If more than annual sampling is required, the water supplier shall report the average sodium concentration within 10 days of the month following the month in which the analytical results of the last sample used for the annual average was received.

NR 809.118(3)(3) Health officials notification. The water supplier shall notify appropriate local health officials of the sodium concentration by written notice by direct mail within 3 months of receipt of sample results. A copy of each notice required to be provided by this subsection and a list of health officials notified shall be sent to the department within 10 days of its issuance.