NR 809.833(2)(c)4.4. “Maximum residual disinfectant level or MRDL: The highest level of a disinfectant allowed in drinking water. There is convincing evidence that addition of a disinfectant is necessary for control of microbial contaminants.”

NR 809.833(2)(d)(d) A report that contains information regarding a Level 1 or Level 2 Assessment required in s. NR 809.313 shall include the following definitions:

NR 809.833(2)(d)1.1. “Level 1 Assessment: A Level 1 assessment is a study of the water system to identify potential problems and determine, if possible, why total coliform bacteria have been found in our water system.”

NR 809.833(2)(d)2.2. “Level 2 Assessment: A Level 2 assessment is a very detailed study of the water system to identify potential problems and determine, if possible, why an E. coli MCL violation has occurred or why total coliform bacteria have been found in our water system, or both, on multiple occasions.”

NR 809.833(3)(3) Information on detected contaminants. With the exception of Cryptosporidium, reports shall contain the following information in the specified format, for regulated contaminants subject to a MCL, action level, maximum residual disinfectant level, microbial contaminants, or treatment technique, unregulated contaminants for which monitoring is required under subch. I, and disinfection by-products for which monitoring is required under subch. III:

NR 809.833(3)(a)(a) The data relating to these contaminants shall be displayed in one table or in several adjacent tables. Any additional monitoring results which a water supplier chooses to include in its report shall be displayed separately.

NR 809.833(3)(b)(b) The data shall be derived from data collected to comply with EPA and department monitoring and analytical requirements during calendar year 1998 for the first report and subsequent calendar years thereafter except that:

NR 809.833(3)(b)1.1. If a public water system is allowed to be monitored for regulated contaminants less often than once a year, the tables shall include the date and results of the most recent sampling and the report shall include a brief statement indicating that the data presented in the report are from the most recent testing done in accordance with the regulations. No data older than 5 years need be included.

NR 809.833(3)(b)2.2. Results of monitoring in compliance with requirements issued under 40 CFR Sub. D, part 141.142 and 141.143 under the information collection rule need only be included for 5 years from the date of last sample or until any of the detected contaminants becomes regulated and subject to routine monitoring requirements, whichever comes first.

NR 809.833(3)(c)3.3. If there is no MCL for a detected contaminant, the table shall indicate that there is a treatment technique, or specify the action level, applicable to that contaminant, and the report shall include the definitions for treatment technique or action level, or both, as appropriate, specified in this paragraph.

NR 809.833(3)(c)4.4. For contaminants subject to an MCL, except turbidity and E. coli, the highest contaminant level used to determine compliance with requirements of this chapter and the range of detected levels as follows:

NR 809.833(3)(c)4.a.a. When compliance with the MCL is determined annually or less frequently: the highest detected level at any sampling point and the range of detected levels expressed in the same units as the MCL.

NR 809.833(3)(c)4.b.b. When compliance with the MCL is determined by calculating a running annual average of all samples taken at a sampling point: the highest average of any of the sampling points and the range of all sampling points expressed in the same units as the MCL. When the MCL for TTHM or HAA5 in s. NR 809.561 (2) is exceeded at a locational running annual average monitoring location, systems must include the highest locational running annual average for TTHM and HAA5 and the range of individual sample results for all monitoring locations expressed in the units as the MCL. If more than one location exceeds the TTHM or HAA5 MCL, the system must include the locational running annual averages for all locations that exceed the MCL.

NR 809.833(3)(c)4.c.c. When compliance with the MCL is determined on a public water system-wide basis by calculating a running annual average of all samples at all sampling points: the average and range of detection expressed in the same units as the MCL.

NR 809.833 NoteNote: When rounding of results to determine compliance with the MCL is allowed by the regulations, rounding should be done prior to multiplying the results by the factor listed in Appendix A of this subchapter.

NR 809.833(3)(c)5.a.a. When it is reported pursuant to s. NR 810.29, the highest average monthly value.

NR 809.833(3)(c)5.b.b. When it is reported pursuant to s. NR 810.29, the highest monthly value. The report should include an explanation of the reasons for measuring turbidity.

NR 809.833(3)(c)5.c.c. When it is reported pursuant to s. NR 810.29, the highest single measurement and the lowest monthly percentage of samples meeting the turbidity limits specified in s. NR 810.29 for the filtration technology being used. The report should include an explanation of the reasons for measuring turbidity.

NR 809.833(3)(c)6.6. For lead and copper: the 90th percentile value of the most recent round of sampling and the number of sampling sites exceeding the action level.

NR 809.833(3)(c)8.8. The likely sources of detected contaminants to the best of the water supplier’s knowledge. Specific information regarding contaminants may be available in sanitary surveys and source water assessments, and should be used when available to the water supplier. If the water supplier lacks specific information on the likely source, the report shall include one or more of the typical sources for that contaminant listed in Appendix A to this subchapter that are most applicable to the public water system.

NR 809.833(3)(d)(d) If a community water system distributes water to its customers from multiple hydraulically independent distribution systems that are fed by different raw water sources, the table should contain a separate column for each service area and the report should identify each separate distribution system. Alternatively, water suppliers could produce separate reports tailored to include data for each service area.

NR 809.833(3)(e)(e) The tables shall clearly identify any data indicating violations of MCLs or treatment techniques and the report shall contain a clear and readily understandable explanation of the violation including: the length of the violation, the potential adverse health effects, and actions taken by the water supplier to address the violation. To describe the potential health effects, the water supplier shall use the relevant language of Appendix A to this subchapter.

NR 809.833(3)(f)(f) For detected unregulated contaminants for which monitoring is required, except Cryptosporidium, the tables shall contain the average and range at which the contaminant was detected. The report may include a brief explanation of the reasons for monitoring for unregulated contaminants.