Current through August 26, 2024
Pitless 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.
