Section NR 811.74 - Separation of water mains and sanitary or storm sewer mains(1) GENERAL. The following factors shall be considered in planning separation of water and sewer mains: materials and type of joints for water and sewer pipes, soil conditions, service and branch connections into the water main and sewer line, compensating variations in the horizontal and vertical separations, space for repair, and alterations of water and sewer pipes.(2) HORIZONTAL SEPARATION. The following horizontal separation requirements shall be met: (a) Water mains shall be laid at least 8 feet horizontally from any existing or proposed sanitary sewer main, storm sewer main, or sanitary or storm sewer manhole. The distance shall be measured center to center.(b) In cases where it is not practical to maintain an 8-foot horizontal separation distance, the department may allow exceptions to that requirement on a case-by-case basis, if supported by data from the design engineer. The following requirements shall be met in order for the department to approve a center to center horizontal separation distance of less than 5 feet:1. The bottom of the water main shall be at least 18 inches above the top of the sewer main and the minimum horizontal separation distance shall be 3 feet measured edge to edge.2. A profile of the rock surface as determined from exploration shall be shown on the plan when high bedrock is the reason for the exception to the 8-foot separation distance. Note: See Figure No. 10 in the Appendix.
(3) VERTICAL SEPARATION. If water mains cross over sanitary or storm sewer mains, the water main shall be laid at such an elevation that the bottom of the water main is at least 6 inches above the top of the sewer main. If water mains cross under sanitary or storm sewer mains, a minimum vertical separation distance of 18 inches shall be maintained between the top of the water main and the bottom of the sewer main. At crossings, one full length of water pipe shall be centered above or below the sewer so that both joints will be as far from the sewer as possible. Special structural support for the water and sewer pipes may be required by the department after a determination that added support is necessary to meet the requirements of this chapter.(4) EXCEPTION. If it is not possible to obtain the proper horizontal and vertical separation as specified in subs. (2) and (3), a gravity sanitary or storm sewer main shall be constructed of materials and with joints that are equivalent to water main standards of construction from manhole to manhole and air pressure tested to assure water tightness in accordance with the 4 psi pressure testing requirements given in s. NR 811.12(5) (d) 2. Department approval is required for any exception to the requirements in subs. (2) and (3).(5) FORCE MAINS. No exception to the 8-foot separation distance may be granted for sanitary sewer force main installations unless the requirement in sub. (2) (b) is met.(6) SEWER MANHOLES. No water pipe may pass through or come into contact with any part of a sanitary or storm sewer manhole.Wis. Admin. Code Department of Natural Resources NR 811.74
CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.