Chapter NR 812

NR 812.152 NR 812.152 Construction requirements for potable high capacity wells, potable school wells, and wastewater treatment plant wells. Potable high capacity wells, potable school wells, and wastewater treatment plant wells shall be planned and constructed according to the location, approval, and general requirements speecified in ss. NR 812.08 to NR 812.12, and according to all of the following requirements:

NR 812.152(1) (1) Minimum diameter. The minimum casing and lower drillhole diameter for potable high capacity wells, potable school wells and wastewater treatment plant shall meet the following requirements:

NR 812.152(1)(a) (a) Four inches for wells completed in unconsolidated formations.

NR 812.152(1)(b) (b) Six inches for wells completed in bedrock formations.

NR 812.152(2) (2) Casing material. Only steel well casing pipe meeting the requirements of s. NR 812.11 (6) may be used.

NR 812.152(3) (3) Upper enlarged drillhole. An upper enlarged drillhole is required for all wells. An upper enlarged drillhole shall be constructed according to the following requirements:

NR 812.152(3)(a) (a) An upper enlarged drillhole shall be a minimum of 3 inches larger than the outside diameter of welded casing pipe, or 3 inches larger than the diameter of the casing couplings, when couplings are used.

NR 812.152(3)(b) (b) The upper enlarged drillhole shall be constructed to at least the minimum casing depth requirements specified in sub. (4).

NR 812.152(3)(c) (c) The upper enlarged drillhole shall be maintained at full diameter for the entire depth by any of the following methods:

NR 812.152(3)(c)1. 1. Circulating bentonite drilling mud.

NR 812.152(3)(c)2. 2. Setting a temporary casing to the bottom of the drillhole, or to the top of bedrock.

NR 812.152(4) (4) Casing depth. Minimum casing depths are measured from the ground surface. All wells shall be constructed with casing that extends to the minimum depth for the geologic formation they are completed in according to the all of the following requirements:

NR 812.152(4)(a) (a) Wells completed in unconsolidated formations.

NR 812.152(4)(a)1. 1. Sixty feet or 20 feet below the static water level when the static water level is greater than 40 feet.

NR 812.152(4)(a)2. 2. One hundred feet, or 20 feet below the static water level when the static water level is greater than 80 feet, when the well is to supply water for a wastewater treatment plant and there is a treatment pond or lagoon or sludge beds on the property.

NR 812.152(4)(b) (b) Wells completed in bedrock.

NR 812.152(4)(b)1. 1. Sixty feet or to the depth of bedrock when the top of bedrock is more than 60 feet below ground surface.

NR 812.152(4)(b)2. 2. One hundred feet when the well is to supply water for a wastewater treatment plant and there is a treatment pond or lagoon or sludge beds on the property.

NR 812.152(5) (5) Grouting. The grouting of an annular space shall be accomplished according to all of the following requirements:

NR 812.152(5)(a) (a) Only neat cement grout meeting the specification under s. NR 812.11 (15) (b) shall be used.

NR 812.152(5)(b) (b) Grout shall be placed using an approved pressure grouting method as specified in s. NR 812.20 (3), except that the grout shall be allowed to set for a minimum of 24 hours before drilling is resumed.

NR 812.152(5)(c) (c) Any temporary casing used during the construction of the upper enlarged drillhole shall be removed.

NR 812.152(6) (6) Driving or advancing casing. Casing may be placed to the bottom of an upper enlarged drillhole meeting the requirements specified in sub. (3) and driven or advanced through unconsolidated material to the final casing depth or to the top of bedrock.

NR 812.152(7) (7) Screens. Screens shall meet all of the following requirements:

NR 812.152(7)(a) (a) Screens shall be continuous-slot screen, v-shaped or wire-wrap on a rod base type and composed of stainless steel or lead-free brass.

NR 812.152(7)(b) (b) Screens may be permanently attached to the casing or riser pipe, or the screen may be placed using the bail-down method or by pushing the screen to the bottom of the casing and pulling it back to expose the screen.

NR 812.152(8) (8) Gravel packs. Gravel packs shall be placed according to the requirements specified in s. NR 812.16.

NR 812.152(9) (9) Geologic samples. Geologic samples shall be collected and submitted according to the requirements specified in s. NR 812.12 (11) (b) from all of the following:

NR 812.152(9)(a) (a) All potable school wells.

NR 812.152(9)(b) (b) High capacity potable wells when required by an approval issued by the department.

NR 812.152 History History: CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7-1-20.

NR 812.16 NR 812.16 Gravel packs.

NR 812.16(1) (1) Conditions. A well driller or a well constructor may construct a screened well with a gravel pack under any of the following conditions:

NR 812.16(1)(a) (a) In an unconsolidated formation well when the natural formation comprising the aquifer is very fine grained or when the aquifer formation is highly variable in size.

NR 812.16(1)(b) (b) In loosely cemented sandstone aquifers that require screening to prevent sand pumping conditions.

NR 812.16(1)(c) (c) In badly fractured or decomposed crystalline bedrock formations.

NR 812.16(2) (2) Material. The gravel or sand used to construct a gravel pack shall meet the requirements specified in s. NR 812.11 (12).

NR 812.16(3) (3) Screens. Screens to be placed in gravel pack wells shall have a set of centering guides on the top and bottom of the screen to ensure an even gravel pack. The screen slot openings shall be sized to retain 90% of the gravel pack. Screen types and materials shall meet the requirements specified in s. NR 812.11 (11). The screen may either be permanently welded or threaded onto the bottom of the well casing pipe or may be installed by pushing the screen to the bottom of the casing pipe and then pulling back the casing pipe to expose the screen.

NR 812.16(4) (4) Placement. Gravel packs shall be placed in accordance with all of the following requirements:

NR 812.16(4)(a) (a) The gravel pack shall be placed through a tremie pipe placed in the annular space.

NR 812.16(4)(b) (b) The gravel pack shall surround the entire screen and shall extend at least 2 feet above the top of the screen.

NR 812.16(4)(c) (c) At least a 2-foot sand seal shall be placed upon the top of the gravel pack to prevent the required annular space sealing material from entering the gravel pack.

NR 812.16(4)(d) (d) For potable wells, the gravel pack may not extend closer to the ground surface than the minimum depth for the upper enlarged drillhole specified in s. NR 812.152 (3).

NR 812.16(4)(e) (e) For nonpotable high capacity wells, the gravel pack may not extend more than 20 feet above the top of the screen.

NR 812.16(5) (5) Thickness. The diameter of the upper enlarged drillhole shall be sized to accommodate the thickness of the gravel pack. The gravel pack shall be at least 2 inches greater than the nominal radius of the screen.

NR 812.16 History History: CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7-1-20.

NR 812.18 NR 812.18 Welding procedures. Plain end well casing pipe shall be welded watertight using welding procedures for plain end well casing pipe in accordance with the specifications in the American Welding Society manual AWS D10.12, “Guide for Welding Mild Steel Pipe.” Well casing pipe to be welded shall conform to the specifications in s. NR 812.11 (6). Pitless adapter connections to well casing pipe shall be made watertight in accordance with welding procedures in the American Welding Society manual AWS D1.1, “Structural Welding Code-Steel.”

NR 812.18 Note Note: Copies of AWS manuals may be obtained directly from the American Welding Society’s website at www.aws.org. Copies are also on file at the offices of the department and the legislative reference bureau.

NR 812.18 History History: CR 18-095: r. and recr., Register June 2020 No. 774, eff. 7-1-20.

NR 812.19 NR 812.19 Well plumbness and alignment. A well driller or well constructor shall construct a well to meet all of the following requirements:

NR 812.19(1) (1) Plumbness. The deviation per 100 feet of well depth from plumb of the center line of the well may not exceed 75% of the well diameter for any well with casing that is 10 inches in diameter or larger.

NR 812.19(2) (2) Alignment.

NR 812.19(2)(a) (a) The well shall allow the free passage of the pump to be permanently installed in the well to the depth of pump setting plus 25% of that depth.

NR 812.19(2)(b) (b) The well shall be aligned so that it does not cause damage to the bearings of a lineshaft turbine pump.

NR 812.19 History History: CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7-1-20.

NR 812.20 NR 812.20 Grouting and sealing. A well driller or well constructor shall complete the grouting or sealing of annular spaces and drillholes using all of the following methods and materials as are applicable:

NR 812.20(1) (1) Grouting and sealing material. Materials used for grouting and sealing shall meet the requirements specified in s. NR 812.11.

NR 812.20(2) (2) General requirements.

NR 812.20(2)(a) (a) Tremie pipes. All of the following general requirements apply to the use of tremie pipes during grouting:

NR 812.20(2)(a)1. 1. The tremie pipe shall be placed to the bottom of the upper enlarged drillhole.

NR 812.20(2)(a)2. 2. When a tremie pipe is placed on the outside of a casing string, it may not be permanently attached to the casing during setting.

NR 812.20(2)(a)3. 3. The tremie pipe shall move freely in the annulus prior to the start of grouting.

NR 812.20(2)(a)4. 4. If the tremie pipe is pulled back during grouting, the bottom of the tremie pipe shall remain submerged in grout.

NR 812.20(2)(a)5. 5. The tremie pipe shall be removed after grouting. If the entire length of tremie pipe cannot be removed after grouting, the driller shall note the reason that the tremie pipe could not be fully removed on the well construction report for the well.

NR 812.20(2)(b) (b) Grouting and sealing. All of the following general requirements apply to the grouting and sealing of wells:

NR 812.20(2)(b)1. 1. Grout shall be placed from the bottom of the annular space to the ground surface.

NR 812.20(2)(b)2. 2. The density of the grout flowing from the annular space at the ground surface shall be the same as the density of the grout being placed.

NR 812.20(2)(b)3. 3. Grout shall be placed in one operation. When grout fails to come to the ground surface in fractured bedrock formations after pumping more than the calculated amount of grout to fill the annulus, the grouting operation may be interrupted to allow the grout to set, or bentonite chips may be used as allowed under s. NR 812.14 (8), and grouting shall continue as soon as possible. If circumstances prevent completing the grouting work in one operation, the well driller or well constructor shall report the reason on the well construction report.

NR 812.20(2)(b)4. 4. Any settling of the grout more than 6 feet below the ground surface shall be made up by adding grout until it comes back up to the ground surface.

NR 812.20(2)(b)5. 5. Cement grouts shall be allowed to set for a minimum of 12 hours before drilling operations continue.

NR 812.20(2)(c) (c) Temporary casing removal. When a temporary outer casing is used to construct the upper enlarged drillhole, a well driller or well constructor shall make an attempt to remove the temporary outer casing during or after the grouting process. If possible, the temporary outer casing shall be removed. The grout level shall remain above the bottom of the casing during removal of the casing.

NR 812.20(3) (3) Pressure grout placement methods. A well driller or well constructor shall complete the pressure grouting of wells using any of the following methods:

NR 812.20(3)(a) (a) Tremie pipe-pumped. The grout material shall be placed by a pump through a tremie pipe into the annular space between the well casing pipe and the upper enlarged drillhole wall or inside surface of the temporary outer casing.

NR 812.20(3)(b) (b) Grout shoe-continuous injection. The grout shoe-continuous injection method of grouting shall be completed in accordance with all of the following:

NR 812.20(3)(b)1. 1. The bottom of the well casing pipe shall be fitted with a grout shoe equipped with a check valve.

NR 812.20(3)(b)2. 2. A tremie pipe or drill stem shall be connected to the grout shoe and shall extend up through the well casing pipe to a grout pump at the ground surface.

NR 812.20(3)(b)3. 3. The well casing pipe shall be suspended a short distance above the bottom of the upper enlarged drillhole.

NR 812.20(3)(b)4. 4. Grout material shall be pumped through the tremie pipe and the grout shoe until the entire annular space is filled with grout.

NR 812.20(3)(b)5. 5. The tremie pipe or drill stem shall be removed and the well casing pipe shall be set to the bottom of the upper enlarged drillhole.

NR 812.20(3)(d) (d) Braden-head method. All of the following requirements apply to the use of the Braden-head method of grouting:

NR 812.20(3)(d)1. 1. The well casing pipe shall be suspended a short distance above the bottom of the upper enlarged drillhole.

NR 812.20(3)(d)2. 2. The well casing pipe and annulus shall be filled with water, drilling mud, or bentonite slurry. A tremie pipe shall be set inside the well casing pipe to the bottom and shall extend watertight through a sanitary well seal installed securely in the top of the well casing pipe. A packer may be installed inside the well casing pipe, at depth, as an alternative to using a well seal at the top.

NR 812.20(3)(d)3. 3. The grout shall be pumped down the tremie pipe and up the annular space.

NR 812.20(3)(d)4. 4. Immediately following grout flow at the surface, the well casing pipe shall be set to the bottom of the upper enlarged drillhole of an unconsolidated formation well or driven to a firm seat in bedrock.

NR 812.20(3)(e) (e) Grout displacement method. The grout displacement method may only be used for wells when the upper enlarged drillhole is less than or equal to 200 feet deep or when drilling mud or bentonite slurry has been circulated in the upper enlarged drillhole from the bottom up to the ground surface prior to the grouting. All of the following requirements apply to the use of the grout displacement method:

NR 812.20(3)(e)1. 1. The well driller or well constructor shall place a measured volume of grout that is equal to the volume of the annular space plus at least 15% into the upper enlarged drillhole through a tremie pipe.

NR 812.20(3)(e)2. 2. The well casing pipe shall be fitted with centering guides and a drillable plug at the bottom and shall be lowered through the grout to the bottom of the upper enlarged drillhole allowing the grout to be forced up into the annular space.

NR 812.20(3)(e)3. 3. If necessary, pressure shall be applied and maintained on the top of the well casing pipe to hold it in place for at least 12 hours or until the grout sets, whichever is longer. Water may be added to the well casing pipe to provide extra weight.

NR 812.20(3)(e)4. 4. If the grout does not flow at the ground surface, the remainder of the annular space shall be filled with grout placed through a tremie pipe that shall be at the drill site.