Section NR 810.12 - Distribution system loss of pressureThe 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:
(1) Notify the appropriate regional office of the department as soon as possible, but no later than one working day after the loss of pressure, as to the extent of the problem, cause and corrective actions taken.(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.(3) Collect distribution system water samples for bacteriological analyses from the pressure loss area as soon as adequate pressure is returned to the water system. The number of samples collected shall increase as the extent of problem areas increases, but in no case may less than 2 samples be collected. The department shall be contacted to determine the number of samples and sampling locations. The water supplier shall comply with s. NR 809.31 when water system sampling indicates the presence of coliform organisms.(4) Issue an immediate boil water notice to all affected water consumers unless it is determined by the department that an acute threat to public health does not exist. The boil water notice shall be maintained until approval is obtained from the department to cease. In this subsection "boil water notice" means a special type of public notice that informs consumers that the water is bacteriologically unsafe and should be boiled prior to consumption. A boil water notice shall include all the following information: (a) The water has tested bacteriologically unsafe for drinking.(b) All water used for washing of eating utensils, drinking, or cooking should be boiled at a rolling boil for at least one minute.(c) Ice and any beverages prepared with unboiled water should be discarded.(d) Precautions listed in subd. 1 to 3 are in effect until further notice.(5) Notify the public in the area affected as prescribed in s. NR 809.951 unless the department determines that no health hazard has existed.(6) Take all corrective actions necessary to prevent additional pressure losses.Wis. Admin. Code Department of Natural Resources NR 810.12
CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.