NR 811.69(4) (4) Protection against corrosion. Special attention shall be given to selecting pipe materials which will protect against internal and external corrosion. If soils, groundwater, or both, are aggressive, ductile iron water mains shall be provided with polyethylene encasement installed in conformity with the latest AWWA standards.

NR 811.69(5) (5) Protection against contamination from organic compounds in soil and groundwater. If possible, construction of water mains through or near areas of soil or groundwater contamination shall be avoided. Special attention shall be given to selecting pipe and gasket materials for construction in contaminated soil or groundwater which will protect against external corrosion and penetration of the pipe and gaskets by the contaminants. Water mains designed to pass through or near areas of contaminated soil or groundwater shall meet the following requirements:

NR 811.69(5)(a) (a) The department shall be contacted to obtain approval of the water main design requirements prior to the submittal to the department of the plans and specifications.

NR 811.69(5)(b) (b) Installations shall meet the following design criteria:

NR 811.69(5)(b)1. 1. Minimum class 52 ductile iron water main piping with polyethylene encasement shall be used.

NR 811.69(5)(b)2. 2. Hydrant drain ports shall be permanently plugged or hydrant barrels installed without drain ports.

NR 811.69(5)(b)3. 3. Nitrile gaskets shall normally be used, except as provided in subd. 4.

NR 811.69(5)(b)4. 4. The use of fluorocarbon gaskets shall be required if:

NR 811.69(5)(b)4.a. a. Nitrile gaskets will not be compatible with the contaminants present.

NR 811.69(5)(b)4.b. b. The soil or groundwater contamination exceeds primary drinking water standards.

NR 811.69(5)(b)4.c. c. The contamination concentrations and locations are uncertain.

NR 811.69(5)(b)5. 5. Pipe bedding shall meet the requirements of s. NR 811.73 (2) (a).

NR 811.69(6) (6) Rehabilitation. All materials used for the interior rehabilitation of water mains shall meet ANSI/NSF standards and may not be used until specifically approved by the department.

NR 811.69 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; correction in (2) made under s. 13.92 (4) (b) 7., Stats., Register December 2011 No. 672; CR 22-074: am. (1), (3) Register January 2024 No. 817, eff. 2-1-24.

NR 811.70 NR 811.70 Water main design. The design of water mains and distribution systems shall meet the following requirements:

NR 811.70(1) (1) General. Water mains and water distribution systems shall be designed and operated to maintain point-of-entry water quality. Special consideration shall be given to distribution main sizing, providing multidirectional flow when possible, providing an adequate number of shut-off valves for distribution system control, providing an adequate number of fire hydrants where fire protection will be provided, and providing for adequate flushing throughout the system. Systems shall be designed to maximize turnover, to minimize the number of dead ends, and to minimize residence times while delivering pressures and flows meeting the requirements under subs. (4) and (6).

NR 811.70(2) (2) Flooding. Any areas of the project which are located within the floodway, as defined in s. NR 116.03 (22), or floodplain as defined in s. NR 116.03 (16), shall be identified on the plans and shall conform to the requirements of that chapter.

NR 811.70 Note Note: Refer to ch. NR 116 for floodway and floodplain requirements.

NR 811.70(3) (3) Wetlands. Any areas of the project which are to be located within a wetland, pass through a wetland or may impact a wetland shall be identified.

NR 811.70 Note Note: Copies of the Wisconsin wetland inventory maps are available for inspection at the office of the department of natural resources and may be purchased through the department’s internet web site.

NR 811.70(4) (4) Pressure. All water mains, including transmission mains and those not designed to provide fire protection, shall be sized after a hydraulic analysis based on flow demands and pressure requirements. The minimum and maximum normal static pressure in the distribution system shall be 35 psi and 100 psi, respectively, at ground level. The system shall be designed and operated to maintain a minimum residual pressure of 20 psi at ground level at all points in the distribution system under all conditions of flow.

NR 811.70(5) (5) Diameter. The minimum diameter of water mains to provide water for fire protection and to serve fire hydrants is 6 inches. Larger mains are required if necessary to allow the required fire flow while maintaining a minimum residual pressure of 20 psi at ground level at all points in the distribution system.

NR 811.70(6) (6) Fire protection. The minimum flow requirement for water mains serving fire hydrants is 500 gpm at 20 psi residual pressure at ground level at all points in the distribution system.

NR 811.70 Note Note: It is recommended that the actual fire flow design be based on the capacity of any fire pumper which may be connected to the water main and the type of services or buildings to be protected. It is also recommended that the local fire department be consulted to discuss needed fire flows before constructing water system improvements.

NR 811.70(7) (7) Small diameter mains. Any departure from minimum requirements shall be justified by hydraulic analysis and future water use, and will be considered for approval by the department only in special circumstances. The main sizing for small diameter mains may be calculated based upon a fixture unit determination.

NR 811.70 Note Note: See the requirements of ch. SPS 382 for guidance in sizing mains according to fixture units to be served.

NR 811.70(8) (8) Dead ends. Dead ends shall be minimized by looping mains whenever possible. Where dead end mains occur, they shall terminate with a fire hydrant, if flow and pressure are sufficient, or with an approved flushing hydrant or blow-off for flushing purposes. Flushing devices shall be installed on the dead end of all water main stubs 20 feet or more in length unless a shut-off valve is installed near the point of connection and closed until the stub is placed in service in the future. Flushing devices shall be sized to provide a minimum velocity of 2.5 feet per second in the water main being flushed. Flushing devices on dead end mains shall be installed downstream of all services. No flushing device shall be directly connected to any sewer.

NR 811.70 Note Note: Refer to AWWA standard C651 for required flows and openings to flush pipelines.

NR 811.70(9) (9) Valving. Sufficient valves shall be provided on water mains so that inconvenience or sanitary hazard to water users will be minimized during maintenance and construction. Valves shall be located at not more than 800-foot intervals for distribution system mains. Valves shall not be located at more than 1-mile intervals for transmission mains and shall be located immediately on each side of a distribution system branch.