Powdered bentonite may be added to the mixture described in par. (b)
up to a ratio of 5 pounds per 94-pound bag of cement.
An additional 0.65 gallons of water per bag of cement may be added to the mix.
Cement-bentonite grout shall have a minimum density of 13.8 pounds per gallon. Grout densities for cement-bentonite mixes are provided in Table C.
Sand-cement grout shall consist of a mixture of cement, sand and water in the proportion of one 94-pound bag of Portland cement, ASTM C 150, Type I or API-10A, Class A; a cubic foot of dry sand and 5 to 6 gallons of water. The sand shall meet the specifications for use in Portland cement concrete.
Concrete shall consist of a mixture of cement, water, sand, and gravel in the following proportion: one 94-pound bag of Portland cement (ASTM C 150, Type I or API-10A, Class A); an equal measure of sand and an equal measure of gravel, by weight or by volume; and not more than 6 gallons of water. As an alternative, a commercially prepared mix may be used if the mix has at least 6 bags of cement per cubic yard and the gravel size does not exceed 1/3 of the inside diameter of the tremie pipe used for filling and sealing the well or drillhole.
Sodium bentonite grout shall be a mixture of sodium bentonite and water that results in a grout containing 20 percent solids, or greater, by weight and shall be mixed according to the manufacturer's specifications.
Drilling mud and cuttings.
Drilling mud and cuttings is a mixture of native clay slurry or bentonite drilling mud mixed with drill cuttings. When allowed as an annular space seal, the mixture of drilling mud and cuttings shall have a mud weight of at least 11 pounds per gallon.
Sodium bentonite-sand grout shall consist of a mixture of sodium bentonite mixed with clean silica sand up to a ratio of a 5 to 1 mixture of clean silica sand to bentonite grout. The clean silica sand used for this mix shall consist of silica sand with 80 percent or more of the sand smaller than 0.0117 inch (passing U.S. Sieve #50) in size.
Bentonite chips shall be commercially prepared and packaged angular fragments of 85% sodium montmorillonite.
Bentonite pellets shall be a commercially prepared and packaged pelletized bentonite product that is coated to delay hydration.
Bentonite granules shall be a commercially prepared and packaged bentonite product consisting of 8 mesh pure bentonite, without additives.
Carbon-bentonite grout shall be a carbon-bentonite premix product that is mixed and used following the manufacturer's specifications. Carbon-bentonite grout shall only be used as a sealing material for heat exchange or anode drillholes.
- See PDF for table
A well driller or well constructor may not use a drilling aid for well and heat exchange drillhole construction and reconstruction unless the drilling aid is approved for use under s. NR 812.091
NR 812.11 History
History: CR 18-095
: r. and recr. Register June 2020 No. 774
, eff. 7-1-20; correction in (6) (c) 4., (15) (i) made under s. 35.17
, Stats., Register June 2020 No. 774
NR 812.12 General drilled type well construction requirements. NR 812.12(1)(1)
A well driller or well constructor shall plan and construct each well to comply with all of the following requirements:
The well shall be adapted to the geologic and groundwater conditions of the proposed well site to ensure full utilization of every natural protection against contamination of the water bearing formation or formations and to exclude possible sources of contamination.
The well shall provide an adequate and contaminant free water supply, where the natural geologic and groundwater conditions allow.
Materials and design.
well driller or well constructor shall construct each drilled well to comply with all of the following:
The requirements specified in s. NR 812.152
for potable high capacity, potable school, and wastewater treatment plant wells.
Special well casing depth areas.
A well driller or well constructor shall provide for greater depth of well casing pipe in special well casing depth areas designated by the department where well histories show contamination extends to a greater depth. In some of these areas department approval shall be obtained for each well prior to construction.
A variance to the setback requirement specified in s. NR 812.08
is not required when the bottom of the quarry is or will be at an elevation higher than the elevation of the ground surface at the well site or if the quarry is no longer used and is permanently filled with water. A well driller or well constructor may construct a well within 500 feet of a quarry if the well is constructed in accordance with all of the following requirements:
The well casing pipe and upper enlarged drillhole depth requirements shall be referenced from the permitted bottom of the quarry.
An additional 20 feet of upper enlarged drillhole and well casing pipe shall be installed over the amount required for the bedrock formation that the well is completed in.
Driving or advancing casing.
A well driller or well constructor may only drive or mechanically advance steel well casing. When a well driller or well constructor drives or advances casing, it shall be done in accordance with all of the following requirements:
A drive shoe or casing shoe meeting the requirements specified in s. NR 812.11 (10)
shall be welded or threaded to the bottom of the casing string.
A drive shoe or casing shoe is not required for any thermoplastic or temporary outer casing.
For a well constructed with thermoplastic casing, the casing may be held down mechanically within an upper-enlarged borehole during grouting to prevent the casing from floating.
Plumbness and alignment.
Well plumbness and alignment shall conform to the requirements specified in s. NR 812.19
upper enlarged drillholes.
A well driller or well constructor shall ensure that any upper enlarged drillhole constructed by the driller is maintained at full diameter during casing setting and grouting.
When a well driller or well constructor constructs a starter drillhole less than or equal to 10 feet deep, the starter drillhole does not need to meet the minimum requirements for upper enlarged drillholes.
The installation of liners shall meet the requirements specified in s. NR 812.21
Grouting and sealing.
A well driller or well constructor shall complete all grouting and sealing requirements using the materials and mixtures specified in s. NR 812.11
and the methods specified in s. NR 812.20
Geologic samples shall be collected by a well driller or well constructor from all of the following:
High capacity potable and nonpotable wells when required by an approval issued by the department.
Cuttings samples shall be collected at 5-foot depth intervals and at each change in geological formation and shall be submitted, along with a copy of the well construction report or a form specified by the department, to the Wisconsin Geological and Natural History Survey no later than 90 days following the completion of the well for the preparation of a geologic log of the well.
Final casing height.
The well driller or well constructor shall complete the well construction such that the well casing pipe extends at least 12 inches above the final ground grade, above a pumphouse or building floor or above any concrete or asphalt platform installed at or above the established ground surface. In addition, for wells in floodplains, the top of the well casing pipe shall terminate at least 2 feet above the regional flood elevation.
A well driller or well constructor shall construct any flowing well in accordance with the requirements specified in s. NR 812.15
The construction of nonpotable wells shall meet the requirements for low capacity potable wells. The drilling mud requirements and the sodium bentonite annular space sealing requirements during well drilling do not apply to nonpotable high capacity wells constructed with reverse rotary methods.
A well driller or well constructor shall develop a new well until the water is practicably clear and free of sand by any one of, or a combination or modification of, the following methods:
A valved or solid plunger surge block may be used to create a surging action in the well. Accumulated material shall be removed periodically. A bailer may be used as the surge block.
An air compressor and piping may be used to create the surging and jetting action in the well. Water in the well shall be alternately brought to the surface by air lift pumping and allowed to drop back down the well to static condition by shutting the air off. This may be performed with an air-rotary drilling rig and drill stem.
Continuous overpumping at a rate of at least 1 1/2 times the design capacity of the well or interrupted overpumping in conjunction with water line drain back to the well in 5-minute cycles may be used. Overpumping alone without a drain back provision or other surging method may not be used to develop screened wells.
A nozzled jetting tool may be used to deliver water at high pressure and velocity to the zone being developed in conjunction with pumping the well.
A well driller or well constructor may use the same technique as hydraulic jetting described in par. (d)
, except with the use of air rather than water.
Well pump test.
The well driller or well constructor shall conduct a pump test using the well driller's, the well constructor's, or the well owner's pump for each new or reconstructed well to determine the stable yield in gallons per minute, and the water level drawdown. A pump test may be conducted using air-rotary equipment. For flowing wells, the flow rate may be measured using an orifice plate with a manometer or equivalent.
NR 812.12 Note
Note: A stable pumping water level may not be possible in wells completed in crystalline bedrock.
A well driller or well constructor shall thoroughly disinfect wells following completion of construction or reconstruction using a chlorine solution such as a sodium or calcium hypochlorite solution. Chlorine compounds having special additives may not be used. A well driller or well constructor shall disinfect wells in accordance with the following requirements:
A chlorine solution with a minimum of 100 mg/L of chlorine shall be used to disinfect wells and well drilling equipment and the disinfectant shall be prepared according to Table D.
The disinfectant shall be dispersed throughout the entire water column in the well. The disinfectant shall also be brought into contact with the inside of the well casing pipe above the static water level.
The disinfectant shall remain in the well for at least 2 hours except for emergency situations, when water is needed without delay. A contact time of at least 30 minutes shall be provided for emergency situations.
A well driller or well constructor shall thoroughly flush wells to remove the chlorine solution after disinfection.
- See PDF for table
Note: mg/L = milligrams per liter (parts per million)
NR 812.12 History
History: CR 18-095
: r. and recr. Register June 2020 No. 774
, eff. 7-1-20; CR 21-070
: am. (5) (b), cr. (5) (c) Register July 2022 No. 799
, eff. 8-1-22.
NR 812.13 Drilled wells terminating in unconsolidated formations.
A well driller or well constructor shall construct wells terminating in unconsolidated material according to the requirements specified in s. NR 812.12
and all of the following:
The minimum diameter for all drilled wells in unconsolidated formations, based on nominal size of well casing pipe, is 2 inches.
Minimum casing depths shall be measured from the ground surface. The minimum well casing pipe depth for all drilled wells in unconsolidated formations, not including any screen, is 25 feet or 10 feet below the static water level when the static water level is greater than 15 feet below ground surface.
Steel or thermoplastic well casing pipe, as specified in s. NR 812.11 (6)
, shall be used for low capacity wells and nonpotable high capacity wells.
Thermoplastic casing may only be placed in an upper enlarged drillhole and may not be driven or jetted into place.
Drilling tools such as drill bits or stabilizers may not be placed in the thermoplastic well casing pipe nor may any drilling or reconstruction occur after placement of the well casing pipe in the well. This restriction does not prohibit the installation or replacement of screens, or the insertion of equipment for the development and cleaning of wells with screens.
A well driller or well constructor shall install an adequate screen when necessary to prevent sand pumping conditions. Screens installed in a well shall meet the requirements of s. NR 812.11 (11)
. A well driller or well constructor shall install screens according to the following requirements:
Screen installation shall be accomplished in a manner that prevents damage to the screen or casing and prevents material from bypassing the well screen.
A packer or shale trap may be used to provide a sand seal between the bottom of a well casing pipe and the top of a screen. Packers and shale traps shall meet the requirements of s. NR 812.11 (13)
A riser pipe may be installed to extend upward from the top of the screen. The riser pipe material shall be thermoplastic or metal provided the metal does not have a lead content in excess of 0.25%.
The construction of a gravel pack well shall comply with the additional requirements specified in s. NR 812.16
Driving or advancing steel well casing.
A well driller or well constructor shall drive or advance casing according to the following requirements:
Clay slurry, sodium bentonite slurry, or granular bentonite shall be maintained around the casing during advancement using any of the following methods:
When casing is driven or advanced from the ground surface, excavating a funnel-shaped depression around the casing to create a reservoir, which shall be kept filled with dry granular bentonite. The granular bentonite shall be kept dry at the surface during advancement.
Filling a starter drillhole or temporary outer casing with clay slurry or sodium bentonite slurry and drill cuttings having a mud weight of at least 11 pounds per gallon, or with dry granular bentonite, which shall be maintained around the outside of the casing.
Constructing an upper enlarged drillhole in accordance with sub. (7)
. The upper enlarged drillhole shall be kept filled to within 10 feet of the ground surface with clay slurry or sodium bentonite slurry and drill cuttings having a mud weight of at least 11 pounds per gallon, or with dry granular bentonite.
Upper enlarged drillhole.
When an upper enlarged drillhole is constructed for any reason, it shall be completed in accordance with all of the following requirements:
The minimum depth of an upper enlarged drillhole shall be one of the following:
To the bottom of any clay formation, or 20 feet, whichever is less when the casing is driven or mechanically advanced as specified in sub. (6) (b) 3.
The minimum diameter of an upper enlarged drillhole shall meet the following requirements:
Four inches greater than the nominal diameter of the casing or couplings.