Section NR 812.15 - Flowing wells(1) CONTROL OF FLOW. When a well driller or well constructor constructs a flowing well, the flow shall be confined to the interior of the well casing. When the flow of water is not contained to the interior of the well casing using planned construction methods, the well driller or well constructor shall notify the department of the location of the flowing well immediately, and take one of the following actions: (a) Reconstruct the well to contain the flow to the interior of the casing.(b) Fill and seal the well according to one of the methods specified in s. NR 812.26 (6) (i).(2) GENERAL REQUIREMENTS. A flowing well constructed with an upper enlarged drillhole shall be grouted in accordance with par. (c). When a new well is constructed to replace a well with uncontrolled flow, the well shall be constructed to meet all of the following requirements: (a)Upper enlarged drillhole requirement. An upper enlarged drillhole shall be constructed in accordance with the requirements specified in subs. (3) or (4).(b)Driving or advancing casing. Steel well casing shall be driven or advanced only through the bottom of an upper enlarged drillhole constructed in accordance with the requirements specified in subs. (3) or (4). The upper enlarged drillhole shall be kept filled with drilling mud with a mud weight of at least 9 pounds per gallon or with dry granular bentonite, which shall be maintained around the outside of the casing. Approved drilling additives may be added to the drilling mud to increase the mud weight.(c)Grouting requirement. The annular space of a flowing well shall be grouted with neat cement using the methods specified in s. NR 812.20.(3) CONSTRUCTION REQUIREMENTS IN UNCONSOLIDATED FORMATIONS. In addition to the general requirements of this section and the requirements specified in ss. NR 812.10 to NR 812.13, a well driller or well constructor shall construct or reconstruct a flowing well in unconsolidated formations according to all of the following requirements: (a)Upper enlarged drillhole. An upper enlarged drillhole shall be constructed to at least 25 feet or halfway through any known confining bed, whichever is deeper, except when the well is double cased in accordance with par. (e).(b)Minimum diameter. The upper enlarged drillhole shall be a minimum of 4 inches larger than the nominal diameter of any casing to be grouted, except as allowed under par. (e).(c)Method of keeping the hole open. The upper enlarged drillhole shall be kept open during construction using any of the following methods: 1. Driving temporary casing to the depth specified in par. (a). 2. Circulating drilling mud with a weight of at least 9 pounds per gallon. Additives approved under s. NR 812.091 may be added to the drilling mud to increase the mud weight.(d)Screens. A well screen may be placed according to the requirements specified in s. NR 812.13 (4) prior to grouting.(e)Double cased wells. When a well is double cased, it shall be constructed in accordance with all of the following requirements: 1. The nominal casing diameter of the outer casing may be reduced to a minimum of 2 inches in diameter greater than the nominal diameter of the inner casing when welded steel or flush-threaded thermoplastic casing is used for an inner casing.2. An upper enlarged drillhole shall be constructed into the confining bed in accordance with par. (c).3. The outer casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues.4. A second upper enlarged drillhole shall be constructed to at least the minimum casing depth for the formation encountered and in accordance with par. (c).5. The inner casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues.(4) CONSTRUCTION REQUIREMENTS IN BEDROCK FORMATIONS. In addition to the general requirements of this section and the requirements specified in ss. NR 812.10 to 812.14, a well driller or well constructor shall construct or reconstruct a flowing well in bedrock formations according to all of the following requirements: (a)Upper enlarged drillhole.1. An upper enlarged drillhole shall be constructed to the minimum casing depth for the bedrock formation encountered or halfway through any known confining bed, whichever is deeper, except when the well is double cased in accordance with par. (e).2. When the depth to the top of bedrock is more than the minimum casing depth for the bedrock formation encountered, the upper enlarged drillhole depth may be reduced to 25 feet below ground surface when steel casing is driven or advanced according to the requirements of sub. (2) (b).(b)Minimum diameter. The upper enlarged drillhole shall be a minimum of 4 inches larger than the nominal diameter of any casing to be grouted, except when the well is double cased in accordance with par. (e).(c)Method of keeping the hole open. The upper enlarged drillhole shall be kept open during construction using any of the following methods: 1. Driving temporary casing to the depth of casing setting or to the top of bedrock.2. Circulating drilling mud with a weight of at least 9 pounds per gallon. Approved additives may be added to the drilling mud to increase the mud weight.(d)Seating casing. Any casing set into an upper enlarged drillhole constructed more than 5 feet into bedrock shall be driven to a firm seat prior to grouting the annular space.(e)Double cased wells. When a well is double cased in bedrock, it shall be constructed in accordance with all of the following requirements: 1. The outer casing may be reduced to a minimum of 2 inches in diameter greater than the nominal diameter of the inner casing when welded steel casing is used as an inner casing. The minimum diameter of an inner casing is 6 inches.2. An upper enlarged drillhole shall be constructed into the confining bed in accordance with par. (c).3. The outer casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues.4. A second upper enlarged drillhole shall be constructed to at least the minimum casing depth for the formation encountered and in accordance with par. (c).5. The inner casing shall be placed in the upper enlarged drillhole and grouted in place according to the requirements specified in sub. (2). The grout shall be allowed to set for a minimum of 24 hours before drilling continues.Wis. Admin. Code Department of Natural Resources NR 812.15
Cr. Register, January, 1991, No. 421, eff. 2-1-91; am. (2) and (3) (intro.), (b) 2. e. and Figure 6, Register, September, 1994, No. 465, eff. 10-1-94; CR 13-099: r. and recr. Figures (5) (b) 1., (6) (b) 1., (7) (b) 2., (9) (c) 1., (10) (c) 2., Register September 2014 No. 705, eff. 10-1-14.Amended by, CR 18-095: r. and recr. Register June 2020 No. 774, eff. 7-1-20; correction in (4) (intro.) made under s. 35.17, Stats., Register June 2020 No. 774, eff. 7/1/2020Amended by, CR 21-070: am. (2) (c) Register July 2022 No. 799, eff. 8/1/2022.