Section NR 811.35 - Pitless unitsPitless units shall be installed in a manner to provide equivalent security, sanitary protection, accessibility, and operational flexibility to an above grade pump discharge installation and in accordance with the requirements of this section and as shown in Figure No. 7 in the Appendix.
(1) TERMINATION. Pitless units shall terminate a minimum of 12 inches above a concrete floor as required by ss. NR 811.12(1) and 811.32(1) (a). If the vent assembly is built into the pitless unit, the portion of the pitless unit where the bottom of the vent assembly is located shall be terminated a minimum of 24 inches above the concrete floor. Pitless units shall be provided with a protective concrete collar where they pass through the concrete floor as required by s. NR 811.32(1) (c). The exterior exposed conduit pipe for the pump wiring shall be rigid steel and the conduit pipe incorporated into the concrete collar.(2) ENCLOSURE. The exposed portion of a pitless unit shall be surrounded by a weather resistant, watertight, locked, and vented enclosure secured to a concrete floor as required by s. NR 811.25(1) (i). The top surface of the concrete floor shall be located a minimum of 6 inches above the finished grade.(3) APPURTENANCES. The top of the pitless unit shall be sealed sanitarily in accordance with s. NR 811.32(1) (b), provided with a well vent and water level measuring equipment in accordance with s. NR 811.36, and shall be provided with a frost-proof down-turned metal smooth end sampling faucet terminating above the top of the pitless unit and a minimum of 12 inches above the concrete floor of the enclosure unless the sampling faucet is installed remote from the pitless unit in accordance with sub. (6) (h).(4) DISCHARGE PIPING. Discharge piping from a pitless unit shall meet the following requirements: (a) The discharge piping from the pitless unit shall be directed to a separate building located above grade where all of the applicable pump discharge piping appurtenances shall be installed in accordance with s. NR 811.37 and Figure No. 7 in the Appendix.(b) The discharge piping from the pump in the well to the above grade pump discharge piping shall remain pressurized at all times. No provisions for drain back of the discharge piping may be allowed. A shut-off valve shall not be installed in the buried portion of the pitless unit discharge piping unless approved by the department as part of a pump-to-waste installation.(c) The buried portion of a pitless unit discharge piping along with any joints or fittings shall be ductile iron, steel, or plastic piping meeting at minimum the AWWA pressure class 150 water main standards required under s. NR 811.69. Plastic piping shall not be used in areas where soil or groundwater contamination may be present. Plastic piping shall be transitioned to metal piping within 12 inches above the floor of the building into which it will be directed, under par. (a), unless minimum schedule 80 PVC pipe is installed in the building as allowed under s. NR 811.28(5) (b). (5) CHECK VALVES. A check valve shall be installed in the submersible pump discharge piping in the well immediately above the pump. A check valve shall not be installed in the buried pitless unit discharge piping. A check valve may not be installed in the above grade pump discharge piping unless preceded by the pump on and off controls, or one or more pressure tanks, or unless the department approves an alternate method to maintain positive pressure in the piping under all operating conditions.(6) SPECIFIC INSTALLATION REQUIREMENTS. (a) Pitless units shall be factory assembled and pressure tested, full length units, with the make and model number having received individual department approval for use. The inside diameter of the pitless unit shall not be smaller than the inside diameter of the well casing pipe as required by s. NR 812.31(2) (b).(b) The department may not approve installation of a pitless unit unless any temporary outer well casing is totally removed from the well during the well construction process. Pitless units shall be attached only to the protective grouted well casing, including wells constructed with gravel packed screens.(c) The top surface of the remaining well grout shall be no greater than one foot below the installation depth of the pitless unit, which is the well casing cut-off depth.(d) The pitless unit shall be installed in accordance with the requirements of s. NR 812.31(3) (a).(e) Pitless units shall be installed by a licensed pump installer. The installed pitless unit shall be tested and proven watertight under a pressure of not less than 14 psig. The pressure shall be maintained for a minimum of 30 minutes. Additionally, any leaks detected shall be sealed during the pressure test. The installer shall notify the department a minimum of 48 hours before performing the pressure testing so that a department employee may witness the test. A report on the results of the pressure testing, signed by a licensed pump installer, shall be submitted to the department before placing the well in service.(f) A certification by the licensed pump installer that installed the pitless unit confirming that the well was originally grouted to the ground surface and that the requirements of pars. (b) and (c) were met, shall be submitted to the department along with the pressure testing report and a copy of the well construction report.(g) Backfilling of the excavation shall commence as soon as practical after the installation and a successful pressure test of the pitless unit.(h) For slab-on-grade enclosures, a below grade length of pump discharge piping from the pitless unit, sufficient to extend beyond the enclosure, shall be installed prior to backfilling of the excavation and construction of the concrete floor slab. The buried piping shall be temporarily capped in a sanitary manner unless the piping is immediately extended and connected to the remainder of the system. During the installation of the discharge piping, if the sampling faucet riser pipe is not installed within the well and pitless unit, a metal riser pipe shall be extended vertically from the below grade discharge piping to terminate at a height a minimum of 12 inches above the top of the future concrete floor. The riser pipe shall be fitted with a frost-proof, down-turned, metal, smooth-end sampling faucet or shall be temporarily capped.Wis. Admin. Code Department of Natural Resources NR 811.35
CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; correction in (6) (intro.) made under s. 13.92(4) (b) 7, Stats., Register November 2010 No. 659.