Chapter NR 812

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 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:

NR 812.13(1) (1) Minimum diameter. The minimum diameter for all drilled wells in unconsolidated formations, based on nominal size of well casing pipe, is 2 inches.

NR 812.13(2) (2) Casing depth. 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.

NR 812.13(3) (3) Casing material and installation.

NR 812.13(3)(a) (a) Steel or thermoplastic well casing pipe, as specified in s. NR 812.11 (6) or (7), shall be used for low capacity wells and nonpotable high capacity wells.

NR 812.13(3)(b) (b) Thermoplastic casing may only be placed in an upper enlarged drillhole and may not be driven or jetted into place.

NR 812.13(3)(c) (c) 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.

NR 812.13(4) (4) 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:

NR 812.13(4)(a) (a) Screen installation shall be accomplished in a manner that prevents damage to the screen or casing and prevents material from bypassing the well screen.

NR 812.13(4)(b) (b) 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).

NR 812.13(4)(c) (c) 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%.

NR 812.13(5) (5) Gravel Packs. The construction of a gravel pack well shall comply with the additional requirements specified in s. NR 812.16.

NR 812.13(6) (6) Driving or advancing steel well casing. A well driller or well constructor shall drive or advance casing according to the following requirements:

NR 812.13(6)(a) (a) The casing shall be equipped with a drive shoe or casing shoe meeting the requirements specified in s. NR 812.11 (10).

NR 812.13(6)(b) (b) Clay slurry, sodium bentonite slurry, or granular bentonite shall be maintained around the casing during advancement using any of the following methods:

NR 812.13(6)(b)1. 1. 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.

NR 812.13(6)(b)2. 2. 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.

NR 812.13(6)(b)3. 3. 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.

NR 812.13(7) (7) 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:

NR 812.13(7)(a) (a) Minimum depth. The minimum depth of an upper enlarged drillhole shall be one of the following:

NR 812.13(7)(a)1. 1. To the final depth that the well casing is set.

NR 812.13(7)(a)2. 2. 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.

NR 812.13(7)(b) (b) Minimum diameter. The minimum diameter of an upper enlarged drillhole shall meet the following requirements:

NR 812.13(7)(b)1. 1. Four inches greater than the nominal diameter of the casing or couplings.

NR 812.13(7)(b)2. 2. A well driller or well constructor may reduce the diameter of an upper enlarged drillhole to 3 inches greater than the nominal diameter of the casing when flush-threaded thermoplastic casing is used and the required sealing material, according to sub. (8), is placed in the annular space using a pressure grouting method according to the requirements of s. NR 812.20.

NR 812.13(7)(b)3. 3. A well driller or well constructor may reduce the upper enlarged drillhole to 2 inches greater than the nominal diameter of the casing when welded steel casing is used and the required sealing material, according to sub. (8), is placed in the annular space using a pressure grouting method according to the requirements of s. NR 812.20.

NR 812.13(7)(c) (c) Method of keeping hole open. A well driller or well constructor shall maintain an upper enlarged drillhole at full diameter during drilling by any of the following methods:

NR 812.13(7)(c)1. 1. Keeping the drillhole filled up to within 10 feet of the ground surface with drilling mud.

NR 812.13(7)(c)2. 2. Circulating bentonite drilling mud.

NR 812.13(7)(c)3. 3. Setting a temporary outer casing.

NR 812.13(7)(d) (d) Grouting. A well driller or well constructor shall grout an upper enlarged drillhole according to the requirements specified in sub. (8).

NR 812.13(8) (8) Grouting material and methods.

NR 812.13(8)(a) (a) Grouting material shall meet the requirements of s. NR 812.11 (15) and shall be placed in an annular space in accordance with the requirements specified in s. NR 812.20. A flowing well shall be grouted using the materials specified in s. NR 812.15. A potable high capacity well shall be grouted using the materials specified in s. NR 812.152.

NR 812.13(8)(b) (b) For a potable low capacity or nonpotable high capacity well with steel casing, a well driller or well constructor shall use one of the following materials:

NR 812.13(8)(b)1. 1. Clay slurry or bentonite drilling mud and cuttings when the upper enlarged drillhole is less than or equal to 20 feet in depth.

NR 812.13(8)(b)2. 2. Neat cement.

NR 812.13(8)(b)3. 3. Sand-cement.

NR 812.13(8)(b)4. 4. Sodium bentonite.

NR 812.13(8)(b)5. 5. Sodium bentonite-sand.

NR 812.13(8)(d) (d) For a potable low capacity or nonpotable high capacity well with thermoplastic casing, a well driller or well constructor shall use one of the following materials:

NR 812.13(8)(d)1. 1. Sodium bentonite.

NR 812.13(8)(d)2. 2. Sodium bentonite-sand.

NR 812.13(8)(d)3. 3. Neat cement.

NR 812.13(8)(d)4. 4. Sand-cement.

NR 812.13(9) (9) Dual aquifer prohibition. A well driller or well constructor may not construct a well that is open to both an unconsolidated formation and a bedrock formation.

NR 812.13 History History: CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7-1-20; correction in (1), (4) (intro.), (8) (b) (intro.), (d) (intro.) made under s. 35.17, Stats., and cr. (7) (a) (title), (b) (title) under s. 13.92 (4) (b) 2., Stats., Register June 2020 No. 774; CR 21-070: am. (3) (c), (4) (b), (8) (a), cr. (8) (d) 3., 4. Register July 2022 No. 799, eff. 8-1-22.

NR 812.14 NR 812.14 Drilled wells in bedrock formations. A well driller or well constructor shall construct wells terminating in bedrock formations according to the requirements of s. NR 812.12 and the construction of wells in bedrock shall be completed to meet all of the following requirements:

NR 812.14(1) (1) Minimum diameter. The minimum diameter for bedrock wells is 6 inches.

NR 812.14(2) (2) Casing depth. Minimum casing depth shall be measured from the ground surface. The following requirements apply to the minimum casing depth in bedrock formations:

NR 812.14(2)(a) (a) Sandstone. Wells completed in sandstone bedrock shall have a minimum of 30 feet of casing.

NR 812.14(2)(b) (b) Crystalline bedrock. Wells completed in crystalline igneous or metamorphic bedrock shall have a minimum of 40 feet of casing.

NR 812.14(2)(c) (c) Limestone or dolomite. Wells completed in limestone or dolomite bedrock shall have a minimum casing depth as follows:

NR 812.14(2)(c)1. 1. Forty feet when the depth to the top of limestone or dolomite is equal to or greater than 20 feet below the ground surface.

NR 812.14(2)(c)2. 2. Sixty feet when the depth to the top of limestone or dolomite is less than 20 feet below the ground surface.

NR 812.14(3) (3) Casing material and installation.

NR 812.14(3)(a) (a) Material. Either steel or thermoplastic well casing pipe meeting the requirements of s. NR 812.11 (6) or (7) may be used as permanent casing for bedrock wells.

NR 812.14(3)(b) (b) Centering. When well casing is set within an upper enlarged drillhole, it shall be centered within the drillhole to ensure an even annular space around the casing. When casing is placed in an upper enlarged drillhole that extends more than 80 feet below ground surface, a drive shoe or casing shoe shall be welded to the bottom of the casing and the casing shall be driven to a firm seat. The department may require, as a condition of an approval or in a special well casing area, that the well casing pipe be centered in the drillhole using any of the following methods:

NR 812.14(3)(b)1. 1. A set of at least 3 centering guides provided at every pipe joint within the bedrock to ensure an even annular space around the well casing pipe. A minimum of 2 sets of 3 centering guides shall be provided, one near the top of the bedrock and one at the bottom of the string of well casing pipe.

NR 812.14(3)(b)2. 2. A drive shoe or casing shoe welded or threaded onto the bottom of the string of well casing pipe and, if the well casing pipe extends more than 63 feet into the bedrock, at least one set of 3 centering guides provided on the casing pipe within the bedrock. If only one set of guides is provided, it shall be installed within 5 feet of the top of the bedrock.

NR 812.14(3)(c) (c) Hung casing pipe prohibition. Casing shall be set to the bottom of an upper enlarged drillhole unless the casing is installed in compliance with the requirements of par. (d).

NR 812.14(3)(d) (d) Screens. Screens may be installed in loosely cemented sandstone wells. The requirements for screen materials and installation of the screen specified in s. NR 812.13 (4) and the requirements for gravel packs specified in s. NR 812.16 apply to drilled wells in bedrock formations.

NR 812.14(3)(e) (e) Thermoplastic casing use restricted. Thermoplastic casing may only be placed in an upper enlarged drillhole and may not terminate in crystalline bedrock or be driven or jetted into place.

NR 812.14(3)(f) (f) Damaged or deformed thermoplastic casing. A well using thermoplastic casing terminating in bedrock shall be free of cracks and free of deformation and the inside diameter shall remain within manufacturer’s specifications after construction or reconstruction. A failed well constructed with thermoplastic casing shall have the casing removed or drilled out prior to filling and sealing.

NR 812.14(3)(g) (g) Drilling tool use restricted. 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 insertion of equipment for the development and cleaning of wells.

NR 812.14(4) (4) Driving or advancing casing. A well driller or well constructor may drive or mechanically advance steel casing from the ground surface to the top of bedrock when the depth to the top of bedrock is equal to the minimum casing depths under sub. (3) or deeper. When steel casing is driven or mechanically advanced to the top of bedrock, it shall be completed in accordance with all of the following:

NR 812.14(4)(a) (a) Drive shoe. The casing shall be equipped with a drive shoe or casing shoe meeting the requirements specified in s. NR 812.11 (10).

NR 812.14(4)(b) (b) Annular space sealing. Clay slurry, sodium bentonite slurry, or granular bentonite shall be maintained around steel casing during advancement using any of the following methods:

NR 812.14(4)(b)1. 1. 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.

NR 812.14(4)(b)2. 2. 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.

NR 812.14(4)(b)3. 3. Constructing an upper enlarged drillhole in accordance with sub. (5). 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 which shall be maintained around the outside of the casing.

NR 812.14(4)(c) (c) Driving to a firm seat. Steel casing shall be driven or advanced to a firm seat into the top of bedrock.

NR 812.14(4)(d) (d) Mechanically holding down thermoplastic casing. For a well constructed with thermoplastic casing, the casing may not be driven to a firm seat. However, the casing may be held down mechanically within an upper enlarged borehole during grouting to prevent the casing from floating.

NR 812.14(5) (5) Upper enlarged drillhole. When a well is constructed with casing that extends 5 feet or more below the top of bedrock, an upper enlarged drillhole shall be constructed to the depth the casing is set. When a well driller or well constructor constructs an upper enlarged drillhole for any reason, it shall be constructed in accordance with all of the following:

NR 812.14(5)(a) (a) Minimum diameter. The minimum diameter of an upper enlarged drillhole shall meet the following requirements:

NR 812.14(5)(a)1. 1. The upper enlarged drillhole shall be 4 inches greater than the nominal diameter of the casing when coupled joints are used.

NR 812.14(5)(a)2. 2. A well driller or well constructor may reduce the diameter of an upper enlarged drillhole to 2 inches greater than the nominal diameter of the casing when welded steel casing is used and the required sealing material, according to the requirements of sub. (7), is placed in the annular space between the upper enlarged drillhole and the well casing pipe using a pressure grouting method according to the requirements of s. NR 812.20.

NR 812.14(5)(b) (b) Method of keeping hole open. A well driller or well constructor shall maintain an upper enlarged drillhole at full diameter during drilling by any of the following methods:

NR 812.14(5)(b)1. 1. Keeping the drillhole filled up to within 10 feet of the ground surface with drilling mud.

NR 812.14(5)(b)2. 2. Circulating bentonite drilling mud.

NR 812.14(5)(b)3. 3. Setting a temporary outer casing to the top of bedrock.

NR 812.14(5)(b)4. 4. Circulating air, air and water, or drilling foam when the drillhole is constructed through non-caving clay, silt, or hardpan.

NR 812.14(5)(c) (c) Minimum depth. The minimum depth of an upper enlarged drillhole shall be one of the following:

NR 812.14(5)(c)1. 1. To the final depth that the well casing is set.

NR 812.14(5)(c)2. 2. To the bottom of any clay formation, or 20 feet, whichever is less, when the casing is driven or advanced to the top of bedrock in accordance with sub. (4) (b) 3.

NR 812.14(5)(c)3. 3. For a well constructed using thermoplastic casing, to a depth not more than 5 feet into the top of firm limestone, dolomite, or shale.

NR 812.14(5)(d) (d) Grouting. A well driller or well constructor shall grout an upper enlarged drillhole according to the requirements specified in sub. (7).

NR 812.14(6) (6) Lower drillhole. A well driller or well constructor shall complete the drilling of a lower drillhole in accordance with all of the following: