Chapter NR 811

NR 811.13(5)(c) (c) Pea gravel that is round, washed to be free of sand and other fine materials, disinfected and having a maximum diameter of 0.375 inches, may be poured into a well without the use of a conductor pipe if the well is sounded at 50-foot intervals to ensure that bridging of the gravel does not occur.

NR 811.13(6) (6) General filling and sealing requirements. Filling and sealing methods shall meet all of the following requirements:

NR 811.13(6)(a) (a) All wells shall be filled from the bottom of the well up to the ground surface using approved materials unless it is necessary to terminate the filling and sealing below the ground surface to accommodate construction over the well. Well casings and filling and sealing materials may be terminated as much as 3 feet below the ground surface or to a depth below any future building foundation to accommodate construction over the well.

NR 811.13(6)(b) (b) The bottom end of the conductor pipe shall be submerged in the sealing material at all times.

NR 811.13(6)(c) (c) Sealing materials shall be placed by use of a conductor pipe or by means of a dump bailer except when approved bentonite chips or pea gravel are used. Bentonite chips may be poured into the well in accordance with sub. (5) (b). Pea gravel may be poured into the well in accordance with sub. (5) (c). Conductor piping used for pressure methods shall meet the requirements of s. NR 811.12 (14) (b) 8. for well grouting. Conductor piping for non-pressure methods shall be one of the following:

NR 811.13(6)(c)1. 1. Metal pipe.

NR 811.13(6)(c)2. 2. Rubber-covered hose reinforced with braided fiber or steel and rated at least 300 psi.

NR 811.13(6)(c)3. 3. For use at depths less than 100 feet, thermoplastic pipe rated for at least 100 psi, including any of the following:

NR 811.13(6)(c)3.a. a. Polyvinyl chloride (PVC).

NR 811.13(6)(c)3.b. b. Chlorinated polyvinyl chloride (CPVC).

NR 811.13(6)(c)3.c. c. Polyethylene (PE).

NR 811.13(6)(c)3.d. d. Polybutylene (PB).

NR 811.13(6)(c)3.e. e. Acrylonitrile butadiene styrene (ABS).

NR 811.13(7) (7) Special filling and sealing requirements. To fill and seal a well, the owner shall have a person who meets the qualifications under sub. (2) fill and seal the well to prevent it from acting as a channel for the vertical movement of contamination or groundwater, by the following applicable method:

NR 811.13(7)(a) (a) Monitoring wells. Monitoring wells constructed to ch. NR 141 requirements shall be filled and sealed in accordance with ch. NR 141 requirements.

NR 811.13(7)(b) (b) Flowing wells. For flowing wells, the flow shall be confined and the well shall be filled in accordance with par. (c), (d), or (e) or sealed in accordance with sub. (6) using neat cement grout applied by a pressure method.

NR 811.13(7)(c) (c) Drift or other unconsolidated wells. For drift or other unconsolidated wells, the well shall be completely filled from the bottom up with concrete, sand cement grout, neat cement, or approved slow-hydrating bentonite chips. Sealing materials shall meet the requirements of sub. (5). An attempt shall be made to remove any inner ungrouted well casings and screens from gravel-pack wells prior to filling. If the well casings and screens cannot be removed, an attempt shall be made to remove as much gravel pack as possible using air or water or both jetting techniques and the interior and exterior of the ungrouted casings and screens shall then be sealed from the bottom up in accordance with sub. (6) using neat cement applied by a pressure method.

NR 811.13(7)(d) (d) Bedrock formation wells. Wells completed in bedrock formations shall be completely filled from the bottom up with concrete, sand-cement, neat cement, or approved slow-hydrating bentonite chips. Sealing materials shall meet the requirements under sub. (5). Wells shall be filled and sealed in accordance with the following formation specific requirements, as applicable:

NR 811.13(7)(d)1. 1. ‘Maquoketa Shale.’ As an alternative for uncontaminated bedrock wells deeper than 250 feet or for wells cased and grouted through the Maquoketa Shale formation, chlorinated, sand-free pea gravel may be used to fill the open drillhole from the bottom of the well up to the 250-foot depth or to a depth 20 feet below the bottom of the protective casing, whichever is deeper. The owner shall contact the department for specific filling and sealing requirements where the top or the bottom of the Maquoketa Shale formation is exposed in the open drillhole.

NR 811.13(7)(d)2. 2. ‘Cambrian Sandstone and Eau Claire formations.’ Minimum 40-foot thick plugs of sealing materials meeting the requirements of under sub. (5) shall be centered at the top of the uppermost Cambrian Sandstone formation and at the top of the Eau Claire formation where these formations are open in the drillhole.

NR 811.13(7)(e) (e) Dug and bored wells. The cover and the top curbing or concrete wall shall be removed to a depth of 5 feet below grade for dug or bored wells. Concrete or rock curbing materials may be caved into the drillhole as the well is being sealed only if performed in a manner to prevent bridging.

NR 811.13(7)(e)1. 1. If constructed in unconsolidated formations, the well shall be filled from the bottom up using clean clay or silt, clean native soil, concrete, sand-cement, neat cement, or approved slow-hydrating bentonite chips or a combination of the above. Sealing materials shall meet the requirements of sub. (5).

NR 811.13(7)(e)2. 2. If constructed partially or completely into bedrock, the well shall be filled from the bottom up to the ground surface with concrete, sand-cement, neat cement, approved slow-hydrating bentonite chips or a combination of the above except that if bedrock is encountered below the ground surface, these materials shall be placed to a point at least 2 feet above the top of the bedrock. The remainder of the well may be filled and sealed with any of the materials listed under subd. 1. Sealing materials shall meet the requirements under sub. (5).

NR 811.13(7)(e)3. 3. Dug or bored wells 18 inches in diameter and smaller shall be filled by means of a conductor pipe, or tremie pipe, except when slow-hydrating bentonite chips are used as specified in sub. (5) (b) or when clean clay or silt or clean native soil is used and the dug or bored well is 25 feet deep or less.

NR 811.13(8) (8) Filling and sealing reports. The person who filled and sealed the well shall file a filling and sealing report with the department, on forms provided by the department, within 30 days after the completion of the well filling and sealing. The report shall be completely filled out in accordance with the information known and shall include complete information on the depths and types of sealing materials used. Well drillers and pump installers shall report to the department any unused or wells that have not been filled and sealed on the property of which they have knowledge.

NR 811.13 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: r. and recr. (title), cr. (intro.), am. (1), (2) (intro.), (3), (4) (title), (a), (c), (d) (intro.), (5) (intro.), (6) (intro.), (a), (7) (intro.), (a), renum. (7) (d) to (7) (d) (intro.) to 2. and am., am. (7) (e) 2., (8) register January 2024 No. 817, eff. 2-1-24; correction in (8) made under s. 35.17, Stats., Register January 2024 No. 817.

NR 811.14 NR 811.14 Special requirements for wells developed in unconsolidated formations.

NR 811.14(1) (1) Cased and grouted depth. The cased and grouted depth for screened wells in unconsolidated formations shall be dependent on the controlling geologic conditions. Where practical, the grouted casing shall extend to at least 5 feet below the normal pumping water level and to within 5 feet of the top of the screen unless the grout depth is at least 60 feet.

NR 811.14(2) (2) Treatment. Additional treatment shall be provided for wells with less than 60 feet of grouted well casing.

NR 811.14(2)(a) (a) Continuous disinfection shall be provided for wells with less than 60 feet of grouted well casing.

NR 811.14(2)(b) (b) Additional detention time and treatment shall be provided when the department determines that additional protection is necessary.

NR 811.14(2)(c) (c) Wells with less than 30 feet of grouted well casing shall be provided with treatment meeting the groundwater under the direct influence of surface water requirements found in ss. NR 810.30, 810.31, 810.33, 810.34, 810.35, 810.36, 810.37, 810.38, 810.39 and 810.40.

NR 811.14(3) (3) Casing and grouting through clay or hardpan. If clay or hardpan is encountered above the formation to be developed, the protective casing and grout shall extend through the materials, but any outer casing shall be withdrawn at least 5 feet above the clay or hardpan during grouting.

NR 811.14(4) (4) Gravel pack. If the well is gravel packed, the gravel shall be acid resistant and free of foreign material, properly sized, washed and disinfected prior to or during placement.

NR 811.14(5) (5) Grout seal. A sand seal, bentonite seal, or seal constructed of both sand and bentonite shall be provided to prevent leakage into the gravel pack. The seal shall be 2 to 4 feet thick.

NR 811.14(6) (6) Gravel refill and observation pipes. Gravel refill pipes and observation pipes, when used, shall be surrounded by a minimum of 1.5 inches of grout if installed in the grouted annular opening. Observation pipes installed between the inner and the protective casing may be plastic. Pipes shall be incorporated into the concrete pump foundation to a point at least 4 inches above the floor, and shall terminate with a threaded cap at least 12 inches above the pumphouse floor.

NR 811.14 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: am. (5) Register January 2024 No. 817, eff. 2-1-24.

NR 811.15 NR 811.15 Special requirements for collector wells.

NR 811.15(1) (1) Continuous disinfection and adequate detention time shall be provided for radial collectors.

NR 811.15(2) (2) Department approval of the well site shall be obtained in accordance with s. NR 811.09 (4) (j) 1. prior to conducting any intensive investigation at the well site.

NR 811.15(3) (3) The area around the collector laterals shall be under the control of the supplier of water for a distance approved by the department.

NR 811.15(4) (4) The location of all caisson construction joints and porthole assemblies shall be indicated on the plans.

NR 811.15(5) (5) The caisson wall shall be constructed of reinforced concrete as provided in s. NR 811.12 (8). An approved water stop shall be installed between each lift. A final water stop or gasket shall be installed between the base of the pumphouse floor and the top of the caisson. All water used in the construction of the collector shall be from a known bacteriologically safe and uncontaminated source.

NR 811.15(6) (6) Provisions shall be made to assure minimum vertical rise of the caisson due to potential buoyancy concerns.

NR 811.15(7) (7) The top of the caisson shall be covered with a watertight concrete floor, and all openings in the floor shall be curbed and have overlapping covers to protect against the entrance of foreign material. The caisson shall be vented through a vent pipe installed through the floor in accordance with the requirements of s. NR 811.64 (8).

NR 811.15(8) (8) Pump discharge pipes may not be placed through caisson walls.

NR 811.15(9) (9) Pumphouses constructed on top of the caisson shall meet the construction requirements of subchs. IV and V. The floor of any pumphouse shall be supported by concrete walls that have frost footings.

NR 811.15 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 811.16 NR 811.16 Special requirements for dug wells and springs.

NR 811.16(1) (1) The department may approve dug wells and springs only when it is not feasible to develop a drilled well.

NR 811.16(2) (2) Dug wells and springs are considered to be groundwater under the direct influence of surface water and shall be provided with treatment meeting the requirements of ss. NR 810.30, 810.31, 810.33, 810.34, 810.35, 810.36, 810.37, 810.38, 810.39 and 810.40.

NR 811.16(3) (3) Dug wells and springs shall be housed in a permanent watertight concrete structure which terminates a minimum of 24 inches above the ground surface, which prevents the entry of surface water, and meets the construction requirements of s. NR 811.12 (8).

NR 811.16(4) (4) Discharge piping for dug wells and springs may not be placed through the sides of the concrete casing.

NR 811.16(5) (5) The supplier of water shall have control of the area around the dug well or spring for a distance approved by the department.

NR 811.16(6) (6) Dug well and spring collector pumping stations shall have a watertight concrete floor. All openings in the floor shall be curbed and protected against the entrance of foreign material. The entrance hatch in the floor shall be located adjacent to the inside of the well perimeter, have a curb at least 4 inches high, have the edge of a gasketed, watertight cover extending down over the curb at least 2 inches, and be kept locked when not in use. The structure shall be vented through a vent pipe installed through the floor in accordance with the requirements of s. NR 811.64 (8).

NR 811.16 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 811.17 NR 811.17 Special requirements for infiltration lines.

NR 811.17(1) (1) The department may approve infiltration lines only when it is not feasible to develop a drilled well.

NR 811.17(2) (2) Infiltration lines are considered to be groundwater under the direct influence of surface water and shall be provided with treatment meeting the requirements of ss. NR 810.30, 810.31, 810.33, 810.34, 810.35, 810.36, 810.37, 810.38, 810.39 and 810.40.

NR 811.17(3) (3) The supplier of water shall have control of the area around the infiltration lines for a distance approved by the department.

NR 811.17 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 811.18 NR 811.18 Special requirements for sandstone wells. The requirements of this section apply to wells drilled in formations commonly referred to as sandstones in Wisconsin. This includes the St. Peter sandstone, the Upper Cambrian sandstones, and the Lake Superior sandstone. All of the following requirements shall be met:

NR 811.18(1) (1) The minimum depth of the grouted casing shall be 60 feet. The grouted casing shall be installed to a depth of 10 feet below the anticipated pumping water level, except in cases when the department determines that this requirement is not necessary to meet the requirements of this chapter.

NR 811.18(2) (2) If the sandstone is overlain by creviced limestone or shale formations, the grouted casing shall be installed a minimum of 15 feet into firm sandstone. The department shall be contacted for the required depth of grouted casing for locations where this type of construction will be required. Wells constructed to utilize aquifers beneath the Maquoketa shale shall be cased and grouted to beneath the depth of the Maquoketa shale.

NR 811.18(3) (3) If the depth of unconsolidated material is more than 60 feet, the grouted casing shall be seated in firm sandstone if the sandstone is the upper rock formation.

NR 811.18(4) (4) If the depth of unconsolidated material is less than 60 feet and the sandstone is the upper rock formation, the department shall be contacted for the required depth of grouted casing.

NR 811.18 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

NR 811.19 NR 811.19 Special requirements for limestone or dolomite wells. This section applies to wells drilled in formations commonly referred to as limestones and dolomites in Wisconsin. This includes the Niagara dolomite, the Galena-Platteville dolomite and the Prairie du Chien dolomite. When an acceptable sandstone aquifer can be utilized, construction of limestone or dolomite wells should be avoided. The following requirements apply to wells located in limestone and dolomite aquifers which are not overlain by consolidated shale or sandstone formations.

NR 811.19(1) (1) At a minimum, continuous disinfection, and possibly detention, shall be provided when the department determines that additional protection is necessary.

NR 811.19(2) (2) Continuous disinfection shall be provided for wells with less than 60 feet of grouted casing.

NR 811.19(3) (3) If the depth of unconsolidated material overlying the limestone is 60 feet or greater for a minimum radius of one-half mile and there is no record of sinkholes, quarries, improperly constructed wells, or outcrops within that area, the minimum depth of grouted casing shall be 60 feet. The department may require greater depths of grouted casing in areas where there is known bacteria or nitrate concentrations exceeding drinking water standards. The casing shall be installed to a depth of 10 feet below the anticipated pumping water level unless the department waives this requirement after finding it unnecessary in meeting the requirements of this chapter.

NR 811.19(4) (4) If the depth of unconsolidated material is more than 60 feet and only 60 feet of grouted casing is required by the department, the casing shall be seated in firm limestone.

NR 811.19(5) (5) If the depth of unconsolidated material is less than 60 feet at the well site or within one-half mile of the well site, the water system owner shall contact the department to determine the required minimum depth of grouted casing. An inner casing size of at least 12 inches in diameter shall be required to permit the installation of a grouted liner at a future date if the water from the well shows evidence of contamination. The department may waive the casing size requirement if it is demonstrated that it is unnecessary to meet the requirements of this chapter, but in that case a minimum of 100 feet of grouted casing is required.

NR 811.19 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10; CR 22-074: am. (3), (5) Register January 2024 No. 817, eff. 2-1-24; correction in (5) made under s. 35.17, Stats., Register January 2024 No. 817.

NR 811.20 NR 811.20 Special requirements for granite wells. The department shall be contacted for specific case-by-case constructional requirements for all proposed developments of wells in Precambrian igneous and metamorphic rock commonly referred to as “granite”. At a minimum, continuous disinfection and possibly detention, shall be provided when the department determines that additional protection is necessary.

NR 811.20 History History: CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.

subch. III of ch. NR 811 Subchapter III — Source Development — Surface Water

NR 811.21 NR 811.21 General requirements. Surface water sources include all lakes, rivers, and streams. The source of water selected by the water system owner as a surface water supply shall be from the best available source practicable. The source shall provide the highest quality water reasonably available which, with appropriate treatment and adequate safeguards, will meet the drinking water standards under ch. NR 809. The water system owner shall contact the department’s office of energy to initiate pre-application consultation regarding ch. 30, Stats., permitting. Any proposal that will result in a diversion from the Great Lakes basin requires department approval under s. 281.346, Stats. A water system that utilizes a surface water source shall meet all of the following requirements:

NR 811.21(1) (1) Quality. The water system owner shall conduct an investigative study that includes both natural and man-made factors that may affect water quality of the selected surface water supply. The study shall include all of the following:

NR 811.21(1)(a) (a) Determining possible future uses of the water body.

NR 811.21(1)(b) (b) Determining degree of control of the watershed by the water system.

NR 811.21(1)(c) (c) Assessing degree of hazard to the water supply by agricultural, industrial, recreational, shipping and residential activities in the watershed, and by accidental spillage of materials that may be harmful or detrimental to the treatment process.

NR 811.21(1)(d) (d) Assessing all waste discharges, point source and non-point source, and activities that could impact the water supply. The location of each waste discharge shall be shown on a scale map.

NR 811.21(1)(e) (e) For lakes, an analysis of the area water currents and for streams, an analysis of streamflows, and their potential impact on water quality. Consideration shall be given to potential wind and ice conditions.

NR 811.21(1)(f) (f) Obtaining samples that are representative of the proposed intake structure based on depth and location. Parameters that may be subject to seasonal variation shall be taken for a period of up to one year or over a sufficient period of time to assess such variation. Testing shall include turbidity, pH, alkalinity, hardness, bromide, total organic carbon, color, taste and odor, ammonia, microbiological organisms, heavy metals including lead and copper, volatile organics, synthetic organics, inorganics, and radiological characteristics of the water. The microbiological testing shall satisfy the Long Term 2 Enhanced Surface Water Treatment Rule requirements found in ss. NR 809.33 to 809.335. The source water shall meet the surface water quality standards in ch. NR 102.

NR 811.21(2) (2) Quantity. The quantity of the water at the source shall:

NR 811.21(2)(a) (a) Be adequate in conjunction with water from other existing sources to meet the maximum 20-year projected water demand of the service area, as shown by calculations based on a one in 50-year drought or the extreme drought of record, and shall include multiple year droughts.

NR 811.21 Note Note: The department recommends water systems using a surface water supply source are provided with redundant intakes or an alternative means of supplying the maximum day water demand.

NR 811.21(2)(b) (b) Provide a reasonable reserve for anticipated growth.