Wisconsin Administrative Code
Department of Natural Resources
NR 800 - Environmental Protection - Water Supply
Chapter NR 812 - Well Construction And Pump Installation
Subchapter II - New Water Well and Heat Exchange Drillhole Construction and Reconstruction and Filling and Sealing of Wells and Drillholes
Section NR 812.26 - Well and drillhole filling and sealing

Universal Citation: WI Admin Code § NR 812.26

Current through August 26, 2024

(1) APPLICABILITY. The requirements of this section apply to all wells and drillholes not regulated under ch. NR 132 or s. NR 141.25. An individual who fills and seals a well or drillhole shall complete the work in accordance with all of the requirements of this section.

(2) PROTECTION OF GROUNDWATER QUALITY. The filling and sealing of noncomplying, unused wells or wells with contaminant levels in excess of the standards specified in s. NR 812.06 or drillholes and noncomplying water systems is a crucial step in the protection of the local groundwater quality. Wells or drillholes, especially those with structural defects, may act as conduits for the vertical movement of contamination from or near the ground surface into the groundwater or from one aquifer to another.

(3) LICENSE REQUIREMENT. An individual who fills and seals a well shall be a licensed water well driller or licensed pump installer and an individual who fills and seals a heat exchange drillhole shall be a licensed heat exchange driller, except that a license is not required for any of the following individuals provided all other requirements of this section are met:

(a) An individual who is employed by a licensed water well driller, licensed pump installer or a person registered as a business to perform well drilling or pump installing may fill and seal a well.

(b) An individual who is a water system operator certified under s. 281.17(3), Stats., and the well is within the service area of the local governmental water system for which the individual works may fill and seal a well.

(c) An individual who is employed by a licensed heat exchange driller or a person registered as a business to perform heat exchange drilling may fill and seal a heat exchange drillhole.

(d) An individual who is filling and sealing a drillhole that was not constructed to obtain groundwater or install a heat exchange loop.

(4) CRITERIA FOR FILLING AND SEALING.

(a) A well or drillhole owner shall hire an individual who meets the license requirements of sub. (3) to fill and seal a well or drillhole in any of the following situations:

1. The well water is contaminated with biological, bacteriological, viral, or parasitic agents and 3 attempts at batch chlorination by a well driller or pump installer fail to eliminate the problem.

2. The well or drillhole poses a hazard to health or safety, or to groundwater.

3. The well or heat exchange drillhole construction or location does not comply with the minimum standards of this chapter.

4. Except as provided in subd. 5., the well has not been used for any water supply purpose for more than 90 days.

5. The well is a seasonal well or high capacity irrigation well that has not been used for any water supply purpose for more than 3 consecutive years.

6. The heat exchange drillhole will not be used as part of the heat exchange system.

7. The pump installation is not operational, or it does not comply with the requirements of this chapter.

(b) The department may require a well or drillhole owner to fill and seal a well or drillhole in any of the following situations:

1. The well or drillhole is required to be filled and sealed under par. (a).

2. The well water contains contaminant levels in excess of the standards specified in s. NR 812.06.

3. The well or drillhole was not constructed by an individual meeting the license requirements of s. NR 812.10(1) or 812.151(1).

(c) A well driller or well constructor shall, no later than 30 days after receiving notice from the department, fill and seal a well that the well driller or well constructor constructed or reconstructed, in any of the following situations:

1. The well construction or location does not comply with the minimum standards of this chapter at the time the well was constructed.

2. The drillhole is an unsuccessful attempt to construct or reconstruct a well.

(d) A heat exchange driller shall, no later than 30 days after receiving notice from the department, fill and seal a heat exchange drillhole that the heat exchange driller constructed, in any of the following situations:

1. The heat exchange drillhole construction or location does not comply with the minimum standards of this chapter at the time it was constructed.

2. The drillhole is an unsuccessful attempt to construct or reconstruct a heat exchange drillhole.

(e) Any person who constructs a drillhole that is not a well or heat exchange drillhole shall fill and seal the drillhole at the completion of drilling and sampling activities.

(f) The department may require any person who has filled and sealed a well or drillhole using a method or material or in a manner not in compliance with this section to take corrective action so that the well or drillhole is filled and sealed in a complying manner.

(5) GENERAL FILLING AND SEALING REQUIREMENTS.

(a) Filling and sealing prior to construction or demolition. Unless exempted under s. NR 123.23, any well or drillhole removed from service shall be filled and sealed prior to any demolition or construction work on the property.

(b) Removal of obstructions prior to filling and sealing. All debris, pumps, piping, ungrouted liner pipe, and any other obstruction known to be in the well or drillhole shall be removed if possible before the well or drillhole is filled and sealed. When a pump is stuck within the well, a reasonable attempt shall be made using the best available technology to pull it out. If the pump cannot be pulled, a tremie pipe shall be placed in the well to a depth just above the top of the pump and neat cement grout shall be pumped in to entomb the pump and fill and seal the entire well.

(c) Circulation of drilling mud in fractured formations. In a highly fractured or highly permeable geologic formation, sodium bentonite drilling mud may be circulated in the drillhole or in the well prior to the filling and sealing procedures.

(d) Use of a tremie pipe. The sealing material to be used to fill and seal a well or drillhole greater than 3 inches in diameter shall be placed through a tremie pipe or by means of a dump bailer except when bentonite chips or bentonite pellets are used. Tremie pipe shall meet the requirements specified in s. NR 812.11(2). The bottom end of the tremie pipe shall be submerged in the filling and sealing material as the grouting proceeds.

(e) Wells or drillholes with inadequate grouting or sealing of the annular space. Wells or drillholes with inadequate grouting or sealing of the annular space outside the well casing pipe or liner shall be filled and sealed. Techniques are situation dependent and may include reaming a new annular space outside the well casing pipe, use of pressure grouting methods, or perforation of the well casing pipe. When perforation of the well casing or liner pipe is undertaken, it shall be done in accordance with the requirements specified in par. (i).

(f) Termination of filling and sealing material. The well casing pipe and filling and sealing material may be terminated as much as 3 feet below the ground surface or to a depth below any future building foundation at the time of the filling and sealing procedure.

(g) Perforation of casing or liner. Well casing or liners with ungrouted annular spaces that cannot be removed from the well or drillhole shall be perforated or ripped in place prior to filling and sealing. When an ungrouted casing or liner is perforated or ripped in place prior to filling and sealing, it shall be completed in accordance with all the following procedures:

1. The casing pipe or liner shall be perforated using projectiles fired perpendicular to the length of the string of pipe. The perforations shall extend completely through the casing or liner pipe. As an alternative, the casing pipe or liner may be vertically ripped.

2. Four perforation shots or one rip shall be provided for each 5 feet of casing or liner.

3. Each perforation shot shall be a minimum of 0.4 inches in diameter. Each rip shall have a minimum width of 0.25 inches and a minimum length of 12 inches.

4. The orientation of each successive perforation shot or rip shall be rotated by 90 degrees along the string of pipe.

5. After the well casing or liner has been perforated or ripped, the well shall be filled completely with neat cement from the bottom up to the ground surface. The well shall be filled both inside and outside the string of casing or liner pipe using a pressure grouting method in accordance with the requirements specified in s. NR 812.20.

(h) Well or drillhole casing pipe. Except as provided under par. (i), (j), or (k), the well casing pipe or drillhole casing pipe shall be left in place when a well or drillhole is filled and sealed. When the well or drillhole casing pipe is removed under par. (i), (j), or (k), the well or drillhole shall be completely filled and sealed with the sealing material as the well casing pipe is pulled or before it is pulled. Any concrete or neat cement grout that settles in the well or drillhole when the well or drillhole casing pipe is removed shall be replaced.

(i) Dry drillholes. Well casing pipe may be removed from a dry drillhole and reinstalled in a well on the same property within 30 days of original drillhole construction.

(j) Reconstruction ordered by the department. Well casing pipe may be removed from a well or drillhole as part of reconstruction ordered or requested by the department. The well casing pipe may only be reinstalled on the same property if the reconstruction takes place no later than 120 days after the original construction.

(k) Dewatering wells or drillholes. Well casing pipe may be removed from a dewatering well or a drillhole. The removed well casing pipe may only be reused for dewatering wells.

(l) Gravel packs. When a well has a gravel pack that extends up to or within 20 feet of the ground surface, at least the top 20 feet of the gravel pack shall be jetted out or removed in some other manner. Once the gravel pack has been removed, the open annular space shall be filled and sealed with neat cement grout or concrete applied with a pressure method injected through a tremie pipe.

(m) Well pits. When a well terminating in a pit is filled and sealed, the pit shall also be filled and sealed, except when the pit is an alcove or if the pit will only be used for the purpose of housing valves and the pit complies with s. NR 812.36(1). The filling of a well pit shall meet all of the following requirements:

1. All water system features shall be removed from the pit prior to filling and sealing.

2. The floor of the pit shall be perforated with several holes.

3. One wall of the pit shall be knocked out or perforated with several holes.

4. The pit shall be filled and sealed with clean native soil less permeable than the soil surrounding the pit.

(n) Nonpressurized conduits. When wells having nonpressurized conduits are filled and sealed, the basement end of the conduit shall be permanently sealed with a watertight cap or seal.

(6) FILLING AND SEALING MATERIALS AND METHODS.

(a) General. Once obstructions have been removed from a well or a drillhole, the well or drillhole shall be filled and sealed, from the bottom up with the use of a tremie pipe, except where the use of a tremie pipe is specifically exempted. As allowed in this section, all materials used to fill and seal wells and drillholes shall meet the specifications of s. NR 812.11(15).

(b) Use of bentonite chips or pellets. Bentonite chips or pellets may be used to fill and seal wells and drillholes, subject to all of the following restrictions:

1. Bentonite chips may not be used for wells and drillholes less than 3 inches in diameter.

2. The total depth may not be deeper than 500 feet and the number of feet of standing water in the well or drillhole may not be more than 350 feet.

3. Bentonite chips or pellets may not be used for any well or drillhole filled with drilling mud or bentonite slurry.

4. Any bentonite chips or pellets placed below the water table shall be screened and poured in a manner that prevents bridging.

5. The depth of bentonite chips or pellets shall be monitored during the filling process, at a minimum of once every calculated 10 bags, to ensure the bentonite chips or pellets are not bridging in the well or drillhole. Any bridge of the bentonite chips or pellets shall be removed.

6. After installing bentonite chips or bentonite pellets, clear water obtained from an uncontaminated source shall be poured into the well to hydrate the bentonite chips. Water shall be introduced until the water level rises to the top of the well casing and the well will not accept any additional water at the time the individual who performs the filling and sealing operation leaves the site.

1. Drilled wells and driven point wells larger than 3 inches in diameter shall be filled and sealed with neat cement grout, sand-cement grout, concrete, bentonite chips, or bentonite pellets.

2. Drilled wells and driven point wells less than or equal to 3 inches in diameter shall be filled and sealed with neat cement grout poured or pumped down the drive pipe or drillhole or by poured bentonite pellets. The use of a tremie pipe is not required.

(d) Drillholes completed in unconsolidated formations.

1. Drillholes less than 3 inches in diameter that extend below the water table shall be filled and sealed with bentonite pellets, or neat cement grout.

2. Drillholes less than 3 inches in diameter that do not extend below the water table may be filled and sealed with granular bentonite.

3. Drillholes 3 inches in diameter or greater shall be filled with drilling mud, cuttings, bentonite pellets, or bentonite chips to fill and seal the drillhole up to 10 feet below ground surface. From the existing ground surface to 10 feet below grade, the drillhole shall be filled with bentonite chips or pellets and hydrated with clear water obtained from an uncontaminated source.

4. The top 18 inches near the surface may consist of asphalt, concrete, sand and gravel base coarse, or native soil. Sealing material in drillholes completed in agricultural areas may be terminated 30 inches below the ground surface and clean native soil may be placed on top of the settled sealing material to avoid interference with agricultural activities.

(e) Wells completed in bedrock formations.

1. Wells completed in bedrock formations shall be filled completely and sealed from the bottom up with neat cement grout, sand-cement grout, concrete, bentonite chips, or pellets except bentonite chips are not allowed for wells and drillholes less than 3 inches in diameter.

2. Chlorinated sand-free pea gravel may be used to fill and seal an uncontaminated bedrock well deeper than 250 feet. Pea gravel may be poured without the use of a tremie pipe provided the well is sounded at 50-foot intervals to prevent bridging. When using pea gravel, the well shall be filled from the bottom up to 20 feet below the bottom of the casing pipe, or up to the 250-foot depth, whichever is deeper.

3. When a well extends through the Maquoketa Shale formation, a neat cement grout, concrete, or bentonite chip or pellet plug at least 40 feet thick shall be placed and centered at the contact surface between the Maquoketa Shale and adjacent geologic formations, both above and below. When a well extends through the top of the uppermost Cambrian Sandstone formation or the top of the Eau Claire Formation of the Cambrian Sandstone, a neat cement grout, concrete, or bentonite chip or pellet plug at least 40 feet thick shall be placed and centered at the upper formation boundary whenever these layers are present in the open bedrock drillhole.

(f) Drillholes completed in bedrock formations. Drillholes completed into bedrock formations shall be filled and sealed from the bottom up with neat cement grout, sand cement grout, bentonite chips, or bentonite pellets except bentonite chips are not allowed for wells and drillholes less than 3 inches in diameter.

(g) Dug and bored wells.

1. Dug or bored wells shall have the cover removed and the top five feet of curbing or concrete wall removed. Rock curbing may be caved into the drillhole as the well is being sealed only if done in a manner to prevent bridging. The well shall be filled and sealed using clean clay or silt, clean native soil, bentonite chips or pellets, concrete, sand-cement grout, or neat cement grout if constructed in unconsolidated formations.

2. Dug or bored wells constructed partially or completely into bedrock shall be filled and sealed with neat cement grout, sand-cement grout, concrete, or bentonite chips or pellets to a point at least two feet above the top of the bedrock. The remainder of the well or drillhole may be filled and sealed using any of the materials listed in par. (c) 1.

3. Dug or bored wells 18 inches in diameter and smaller shall be filled and sealed by means of a tremie pipe, except when bentonite chips or pellets are used or when clean clay or silt or clean native soil is used and the dug or bored well is 25 feet deep or less.

(h) Heat exchange drillholes. The filling and sealing of heat exchange drillholes shall be completed according to all of the following requirements:

1. If the loops for a heat exchange drillhole have not been grouted in place and can be removed from the drillhole, the loops shall be removed before filling and sealing.

2. If the loop for a heat exchange drillhole has been grouted into the drillhole and cannot be removed, the loop shall be evacuated of all fluids and cement or bentonite grout shall be pumped into the loop. The loops may be left in place after grouting or may be cut off below ground surface.

(i) Flowing wells. Materials for filling and sealing a flowing well shall be neat cement or neat cement with approved additives to increase the grout density and shall meet the requirements of s. NR 812.11(15). The flow of water at the ground surface from a flowing well shall be reduced or stopped prior to filling and sealing using one of the following methods:

1. Centering a tremie pipe in the drillhole or casing within an inflatable packer.

2. Extending the well casing to a height above the piezometric surface.

3. Placing chlorinated sand-free pea gravel in a bedrock well from the bottom of the well to no higher than 40 feet from the bottom of the casing pipe.

4. Pumping water out of a nearby well completed in the same flowing formation.

(7) WELL AND DRILLHOLE FILLING AND SEALING REPORTS.

(a) A well and drillhole filling and sealing report shall be filed with the department no later than 30 days after the well or drillhole is filled and sealed.

(b) The filling and sealing report shall be filed with the department electronically by the person performing the filling and sealing work and shall include all of the following information:

1. A complete and accurate description of the location of the well or drillhole that was filled and sealed.

2. The materials and method of filling and sealing.

3. The construction of the well or drillhole.

4. The geologic features of the well or drillhole.

5. The Wisconsin Unique Well Number of the well, if known.

6. The presence of any unused wells or drillholes that are not filled and sealed for which they have knowledge.

Disclaimer: These regulations may not be the most recent version. Wisconsin may have more current or accurate information. We make no warranties or guarantees about the accuracy, completeness, or adequacy of the information contained on this site or the information linked to on the state site. Please check official sources.

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