Wisconsin Administrative Code › Department of Natural Resources › NR 800 - Environmental Protection - Water Supply › Chapter NR 812 - Well Construction And Pump Installation › Subchapter III - Requirements for New Pump Installations and Water Treatment › Section NR 812.33 - Water storage vessels

Current through June 24, 2024
The department recommends that pressure tanks be
					 sufficiently sized to provide the minimum pump run time recommended by the pump
					 manufacturer.
Note:
Community water systems regulated under
					 ch. NR 811 are required to have a gross pressure tank volume of 10 times the
					 pump capacity.
(1) PRESSURE TANKS.
(a)
General.
Tanks relying
				  on expansion of a flexible membrane within a restricting container, rather than
				  on a water to air interface to provide pressure in the water system, may be
				  used. All pressure tanks for storing potable water under pressure, including
				  those having an air space for expansion, shall be identified by seal, label or
				  plate indicating the manufacturers name and model number and shall meet the
				  following specifications:
1. Pressure tanks to
				  be buried shall be constructed of steel, fiberglass or other comparable
				  non-metallic composite material. Steel tanks with metallic discharge piping,
				  meeting the requirements of s. NR 812.28, shall be used in contaminated soil
				  areas. Steel tanks to be buried shall have a minimum wall thickness of 0.25
				  inches. Fiberglass or other non-metallic tanks to be buried shall have the
				  structural strength to prevent collapse of the tank. Manufacturer's
				  instructions shall be followed. All buried tanks shall be back-filled in place
				  with sand, compacted in place. Steel pitless receiver tanks, when they are part
				  of approved pitless units attached directly to the well casing pipe, shall also
				  have a minimum wall thickness of 0.25 inches. Any air unloader pipe, tank air
				  valve or any other pipe connection extending up to the ground surface shall be
				  steel pipe meeting the requirements of s. NR 812.28 and shall terminate at
				  least 12 inches above ground grade.
Note:
The department recommends that a surface
					 air check kit be installed for a buried pressure tank to check, maintain and
					 adjust the air pressure pre-charge of the tank. Also, in uncontaminated soil
					 areas, pipe and pipe connections to the tank should be made with flexible pipe
					 and fittings meeting the requirements of s. NR 812.28 to minimize strain or
					 pressure on the tank or the tank fittings.
2. Pressure tanks having a gross volume in
				  excess of 500 gallons, and not having a water to air interface bladder, shall
				  have the following:
a. If the tank is buried,
				  all electrical controls extended to at least above ground grade.
b. Each tank shall have an access manhole, a
				  drain, and pressure gauge, pressure relief valve, water sight glass and
				  pressure or probe operated controls for the pumps.
c. An air compressor or other suitable means
				  to add air to the tank.
d. Any
				  interior protective materials including but not limited to liners, paints,
				  coatings, or sealants shall be certified for potable water use under NSF
				  Standard 61.
Note:
The department recommends that the tank
					 have bypass piping to allow operation of the system while the tank is being
					 repaired or painted.