NR 810.09(2)(a)(a) All municipal water systems shall provide continuous disinfection of the water prior to entry to the distribution system within 36 months of December 1, 2010. For systems that provide disinfection by chlorination, chloramination, or chlorine dioxide, a detectable residual shall be provided throughout the distribution system.

NR 810.09 NoteNote: It is recommended that all community water systems provide a detectable disinfectant residual throughout the distribution system.(b) When disinfection of water drawn from a groundwater source is required in order to meet the MCL for total coliform or E. coli contained in ch. NR 809 to maintain bacteriologically safe water, the residual maintained in the distribution system and the residual monitoring shall be as required in ss. NR 809.74 (2) and NR 811.43 (2). Additional disinfection requirements including disinfectant contact time or compliance with the disinfection requirements of s. NR 810.31 (1) may be required by the department on a case-by-case basis. The following conditions, as well as other conditions, are considered by the department to be existing or potential water system public health threats:

NR 810.09(3)(a)(a) For free chlorine, the concentration in the water entering the distribution system of any public water system, primary or consecutive, served by treated surface water shall be at least 0.2 mg/1 at the entry point to the distribution system and detectable throughout the distribution system. For total combined chlorine, the concentration in the water entering the distribution system of any public water system served by treated surface water shall be at least 1.0 mg/l at the entry point to the distribution system and detectable throughout the distribution system. Residual monitoring of the water entering the distribution system shall be provided as required in s. NR 809.74 (2).

NR 810.09(4)(a)(a) After construction, maintenance, repair or modification, waterworks facilities shall be disinfected by procedures outlined in the following A.W.W.A. Standards: A100 (August 1, 2006) for wells, C651 (June 1, 2005) for water mains, C652 (August 1, 2002) for water storage facilities, C653 (June 1, 2003) for water treatment plants or C654 (November 1, 2003) for wells. In addition, waterworks may not be placed in service until bacteriological samples have established that the water is safe for consumption in accordance with par. (b).

NR 810.09 NoteNote: Copies of these standards are available for inspection at the office of the Department of Natural Resources and the Legislative Reference Bureau, and may be obtained for personal use from the American Water Works Association, 6666 West Quincy Ave., Denver, Colorado, 80235.

NR 810.09(4)(b)(b) At least one bacteriologically safe sample shall be obtained before waterworks are placed into service. In the case of new or reconstructed wells, a minimum of 2 bacteriological safe samples, taken at least 8 hours apart during the test pumping period, or on 2 separate days, shall be obtained. When new distribution systems or extensions on a number of streets are installed, bacteriological samples shall be taken at representative locations to establish that all of the improvements are free of contamination. When water main breaks are repaired in public water systems that do not maintain a detectable chlorine residual, a bacteriological sample shall be taken in the area of the break within one working day. The main may be returned to service prior to receiving the results provided that the main has been disinfected and flushed. The water supplier shall comply with s. NR 809.31 when system sampling indicates the presence of coliform organisms. For water storage facilities, 2 or more successive safe samples, taken at 24-hour intervals, shall be obtained which indicate bacteriologically safe water or one safe sample shall be obtained only if a free chlorine residual of at least 0.1 mg/l is remaining when the results of the safe sample are reported.

NR 810.09(5)(5) Indirect additives. Written approval from the department is required prior to the use of any indirect chemical or material that may affect the quality of the water supply due to immersion or incidental contact in the water system. Department approval shall include certification of the chemical or material for use in potable water under NSF/ANSI Standard 61. Laboratories evaluating products for compliance with NSF/ANSI Standard 61 shall be certified by the American National Standards Institute. Written department approval is not required where existing equipment is being replaced with similar equipment during maintenance or repair provided that the water supplier can document that the equipment used meets the approval requirements of this section.

NR 810.10NR 810.10 Distribution system normal pressure. For community water systems, the system pumps, the distribution system and related storage facilities shall be operated to maintain a minimum of 35 pounds per square inch and a maximum of 100 pounds per square inch at ground level above the water main at all locations in the distribution system under normal operating conditions. Normal operating conditions include the peak hour demand on the maximum day. Where the storage or primary pumping facilities cannot provide a minimum static pressure of 35 psi throughout the distribution system at street elevation it shall be necessary to create a boosted pressure zone to serve those portions of the system. The use of pressure boosting systems on individual service lines shall be limited to a maximum of 10 individual systems in any given service area. The individual pressure boosting systems shall be owned and maintained by the public water system owner. The department may require pressure testing to determine whether adequate pressures are available. In situations where static pressures exceed 100 psi, pressure reducing devices may be required on mains in distribution systems having documented system deficiencies or problems due to high pressure such as main breaks and service line breaks.

NR 810.11NR 810.11 Distribution system fire flow pressure. Community water systems with fire protection shall be operated so that under fire flow conditions the residual pressure in the distribution system is not less than 20 pounds per square inch at ground level. Water suppliers shall maintain current flow studies showing the fire flow capability of the system. Fire pumpers may not be connected to fire hydrants if 20 psi cannot be maintained in the system during operation of the pumpers. In addition, the public water system owner shall notify the fire chief in writing of the location of all fire hydrants that cannot be used by fire pumpers and color code or tag the affected hydrants. The department may require pressure and flow testing to determine whether adequate flows and pressures are available.

NR 810.12NR 810.12 Distribution system loss of pressure. The water supplier for community water systems shall be responsible for taking corrective action when positive distribution system pressure is lost in an area affecting 25% or more of the overall distribution system or in an entire pressure zone. In addition to restoring system pressure, the water supplier shall perform all of the following:

NR 810.12(2)(2) Start emergency disinfection of the water supply if the water system is not already continuously disinfected. At a minimum, the free chlorine residual shall be 0.2 mg/l at the entry point to the distribution system and detectable throughout the distribution system or the total combined chlorine residual shall be 1.0 mg/l at the entry point and detectable throughout the distribution system. If loss of pressure was limited to one pressure zone, the above disinfection requirements may be restricted to target the affected pressure zone. Higher disinfectant residuals may be required by the department if deemed necessary to ensure a safe water supply. Water mains and storage facilities in the area that lost pressure shall be flushed to remove contaminated water and to quickly establish an adequate disinfectant residual. Emergency disinfection shall be maintained until approval is obtained from the department to cease.