NR 809.31(1)(dg)2.2. The most recent sanitary survey shows that the transient non-community system is free of sanitary defects or has corrected all identified sanitary defects, has a protected water source, and meets approved construction standards.

NR 809.31(1)(dg)3.3. The department has conducted an annual site visit within the last 12 months and the water supplier has corrected all identified sanitary defects. A Level 2 assessment that meets the criteria in s. NR 809.313 (2) may be substituted for the department annual site visit.

NR 809.31(1)(dr)(dr) Seasonal system requirements.

NR 809.31(1)(dr)1.1. Beginning April 1, 2016, all water suppliers of seasonal systems shall demonstrate completion of a department-approved start-up procedure, which may include a requirement for start-up sampling prior to serving water to the public.

NR 809.31(1)(dr)2.2. Seasonal systems shall be monitored every month that they are in operation unless they meet the criteria in subd. 2. a. to c. to be eligible for monitoring less frequently than monthly beginning April 1, 2016, except as provided under par. (ar).

NR 809.31(1)(dr)2.a.a. Seasonal systems that are monitored less frequently than monthly shall have an approved sample siting plan that designates the time period for monitoring based on site-specific considerations (e.g., during periods of highest demand or highest vulnerability to contamination). Water suppliers of seasonal systems shall collect compliance samples during this time period.

NR 809.31(1)(dr)3.3. The department may exempt any seasonal system from some or all of the requirements for seasonal systems if the entire distribution system remains pressurized during the entire period that the seasonal system is not operating, except that seasonal systems that are monitored less frequently than monthly shall be monitored during the vulnerable period as designated by the department.

NR 809.31(1)(e)(e) Sample collection time intervals. Water suppliers for public water systems shall collect samples at regular time intervals throughout the month, except that for public water systems which use only groundwater and serve 4,900 persons or fewer, may collect all required samples on a single day if the samples are taken from different sites.

NR 809.31(1)(eg)(eg) Minimum required number of samples after MCL violation or treatment technique trigger. Water suppliers shall take at least the minimum number of required samples even if the public water system has had an E. coli MCL violation or has exceeded the coliform treatment technique triggers in s. NR 809.313.

NR 809.31(1)(er)(er) Sampling in excess of requirements. Water suppliers may conduct more compliance monitoring than is required by this section to investigate potential problems in the distribution system and use monitoring as a tool to assist in uncovering problems. Water suppliers may take more than the minimum number of required routine samples and shall include the results in calculating whether the coliform treatment technique trigger in s. NR 809.313 has been exceeded only if the samples are taken in accordance with the existing sample siting plan and are representative of water throughout the distribution system.

NR 809.31(1)(f)(f) Special purpose samples. Special purpose samples such as those taken to determine whether disinfection practices are sufficient following pipe placement, replacement or repair, may not be used to determine whether the coliform treatment technique trigger has been exceeded. Repeat samples taken pursuant to sub. (2) are not considered special purpose samples, and shall be used to determine whether the coliform treatment technique trigger has been exceeded.

NR 809.31(1)(g)(g) Analyses required after turbidity exceedances at selected systems. A water supplier for a public water system that uses surface water or groundwater under the direct influence of surface water as defined in s. NR 809.04 (40), and does not provide filtration in compliance with s. NR 810.29, shall collect at least one sample in the distribution system near the first service connection each day one or more turbidity measurements of the source water obtained as specified in s. NR 810.38 (1) (c), exceeds 1 NTU. This sample shall be analyzed for the presence of total coliforms. The water supplier shall collect this coliform sample within 24 hours of the first exceedance unless the department determines that the water supplier, for logistical reasons beyond their control, cannot have the sample analyzed within 30 hours of collection. Results from this coliform monitoring shall be used to determine whether the coliform treatment technique trigger has been exceeded in s. NR 809.313.

NR 809.31(2)(a)(a) If a routine sample is total coliform-positive, the water supplier for a public water system shall collect a set of repeat samples within 24 hours of being notified of the positive result. The water supplier shall collect no fewer than 3 repeat samples for each total coliform-positive sample found. The department may extend the 24-hour limit on a case-by-case basis if the water supplier has a logistical problem that is beyond its control in collecting the repeat samples within 24 hours. In the case of an extension, the department shall specify how much time the water supplier has to collect repeat samples. The department may not waive the requirement for a water supplier to collect repeat samples in this paragraph or pars. (b) to (c).

NR 809.31(2)(b)(b) Unless the provisions of subds. 1. and 2. are met, the water supplier shall collect at least one repeat sample from the sampling tap where the original total coliform-positive sample was taken, and at least one repeat sample at a tap within 5 service connections upstream and at least one repeat sample at a tap within five service connections downstream of the original sampling site. If a total coliform-positive sample is at the end of the distribution system, or one service connection away from the end of the distribution system, the water supplier shall take all required repeat samples. However, the department may allow an alternative sampling location in lieu of the requirement to collect at least one repeat sample upstream or downstream of the original sampling site. Except as provided in subd. 2., public water systems required to conduct triggered source water monitoring under s. NR 809.325 shall take ground water source samples in addition to repeat samples required under this paragraph.

NR 809.31(2)(b)1.1. A water supplier may propose repeat monitoring locations to the department that the water supplier believes to be representative of a pathway for contamination of the distribution system. A water supplier may elect to specify either alternative fixed locations or criteria for selecting repeat sampling sites on a situational basis in a standard operating procedure (SOP) in its sample siting plan. The water supplier shall design its SOP to focus the repeat samples at locations that best verify and determine the extent of potential contamination of the distribution system area based on specific situations. The department may modify the SOP or require alternative monitoring locations as needed.

NR 809.31(2)(b)2.2. A water supplier of a ground water system serving 1,000 or fewer people may propose repeat sampling locations to the department that differentiate potential source water and distribution system contamination (e.g., by sampling at entry points to the distribution system). A water supplier of a ground water system with a single well required to conduct triggered source water monitoring may, with written department approval, take one of the repeat samples at the monitoring location required for triggered source water monitoring under s. NR 809.325 if the water supplier demonstrates to the department’s satisfaction that the sample siting plan remains representative of water quality in the distribution system. If approved by the department, the water supplier may use that dual purpose sample result to meet the monitoring requirements in both s. NR 809.325 and this section.

NR 809.31(2)(b)2.a.a. If a dual purpose repeat sample taken at the monitoring location required for triggered source water monitoring is E. coli-positive, the public water system has violated the E. coli MCL and shall also comply with s. NR 809.325 (2) (e). If a water supplier takes more than one repeat sample at the monitoring location required for triggered source water monitoring, the water supplier may reduce the number of additional source water samples required under s. NR 809.325 (2) (e) by the number of repeat samples taken at that location that were not E. coli-positive.

NR 809.31(2)(b)2.b.b. If a water supplier takes more than one repeat sample at the monitoring location required for triggered source water monitoring under s. NR 809.325 (2). and more than one repeat sample is E. coli-positive, the public water system has violated the E. coli MCL and shall comply with s. NR 809.327.

NR 809.31(2)(b)2.c.c. If all repeat samples taken at the monitoring location required for triggered source water monitoring are E. coli-negative and a repeat sample taken at a monitoring location other than the one required for triggered source water monitoring is E. coli-positive, the public water system has violated the E. coli MCL, but is not required to comply with s. NR 809.325 (2) (e).

NR 809.31(2)(b)3.3. The department may review, revise, and approve, as appropriate, repeat sampling proposed by water suppliers under subds. 1. and 2. The water supplier shall demonstrate that the sample siting plan remains representative of the water quality in the distribution system. The department may determine that monitoring at the entry point to the distribution system, especially at ground water systems without disinfection is effective to differentiate between potential source water and distribution system problems.

NR 809.31(2)(c)(c) Water suppliers at ground water systems may use a repeat sample, taken at the source or all of the sources serving the location of each routine positive sample, to meet the requirements of both this paragraph and s. NR 809.325 (2) (d). In cases where more than one source serves the location of the routine positive sample or samples, repeat samples shall be taken from each of the sources to satisfy the requirements of this paragraph and s. NR 809.325 (2) (d).

NR 809.31(2)(d)(d) The water supplier shall collect all repeat samples on the same day, except that the department may allow a water supplier for a public water system with a single service connection to collect the required set of repeat samples over a 3-day period or to collect a larger volume repeat sample in one or more sample containers of any size, as long as the total volume collected is at least 300 mL.

NR 809.31(2)(e)(e) If one or more repeat samples in the set is total coliform-positive, the water supplier shall collect an additional set of repeat samples in the manner specified in pars. (a) to (d). The additional set of samples shall be collected within 24 hours after the water supplier is notified of the positive result, unless the department extends the limit as provided in par. (a). The water supplier shall repeat this process until either total coliforms are not detected in one complete set of repeat samples or the water supplier determines that the coliform treatment technique trigger specified in s. NR 809.313 has been exceeded and the water supplier notifies the department as specified in s. NR 809.80 (2). If a trigger identified in s. NR 809.313 is exceeded as a result of a routine sample being total coliform-positive, water suppliers are required to conduct only one round of repeat monitoring for each total coliform-positive routine sample.

NR 809.31(2)(f)(f) Water suppliers collecting samples on a quarterly or annual frequency shall conduct additional routine monitoring the month following one or more total coliform-positive samples regardless of whether the positive samples resulted in a Level 1 treatment technique trigger. Water suppliers shall collect at least three routine samples during the next month, after consultation with the department, except that the department may waive this requirement if the conditions of subd. 1., 2., or 3. are met. Water suppliers may either collect samples at regular time intervals throughout the month or may collect all required routine samples on a single day if samples are taken from different sites. Water suppliers shall use the results of additional routine samples in coliform treatment technique trigger calculations under s. NR 809.313 (1).