Section 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:
(1) MINIMUM DIAMETER. The minimum diameter for all drilled wells in unconsolidated formations, based on nominal size of well casing pipe, is 2 inches.(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.(3) CASING MATERIAL AND INSTALLATION.(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.(b) Thermoplastic casing may only be placed in an upper enlarged drillhole and may not be driven or jetted into place.(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.(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:(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.(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).(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%.(5) GRAVEL PACKS. The construction of a gravel pack well shall comply with the additional requirements specified in s. NR 812.16.(6) DRIVING OR ADVANCING STEEL WELL CASING. A well driller or well constructor shall drive or advance casing according to the following requirements: (a) The casing shall be equipped with a drive shoe or casing shoe meeting the requirements specified in s. NR 812.11 (10).(b) Clay slurry, sodium bentonite slurry, or granular bentonite shall be maintained around the casing during advancement using any of the following methods: 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.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.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.(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: (a)Minimum depth. The minimum depth of an upper enlarged drillhole shall be one of the following: 1. To the final depth that the well casing is set.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.(b)Minimum diameter. The minimum diameter of an upper enlarged drillhole shall meet the following requirements:1. Four inches greater than the nominal diameter of the casing or couplings.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 812.20.3. 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.(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:1. Keeping the drillhole filled up to within 10 feet of the ground surface with drilling mud.2. Circulating bentonite drilling mud.3. Setting a temporary outer casing.(d)Grouting. A well driller or well constructor shall grout an upper enlarged drillhole according to the requirements specified in sub. (8).(8) GROUTING MATERIAL AND METHODS. (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.(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: 1. Clay slurry or bentonite drilling mud and cuttings when the upper enlarged drillhole is less than or equal to 20 feet in depth.5. Sodium bentonite-sand.(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: 2. Sodium bentonite-sand.(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.Wis. Admin. Code Department of Natural Resources NR 812.13
Cr. Register, January, 1991, No. 421, eff. 2-1-91; am. (2) (a) 2., (b) 1., (3) (a) 1. and (b) 4., Register, September, 1994, No. 465, eff. 10-1-94; correction in (2) (e) 1., made under s. 13.93(2m) (b) 1, Stats., Register, September, 1996, No. 489 CR 13-099: am. (3) (b) 7., Register September 2014 No. 705, eff. 10-1-1.Amended by, 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, eff. 7/1/2020Amended by, CR 21-070: am. (3) (c), (4) (b), (8) (a), cr. (8) (d) 3., 4. Register July 2022 No. 799, eff. 8/1/2022.