Section 812.21. Liners.

  Only new steel or thermoplastic well casing pipe as specified in s. NR 812.17 may be used for liner pipe.

(1)   Liners installed to correct contaminated water supplies, to line-off the vertical zone of contamination, or to prevent cross-migration between aquifers. Liner pipe installed in a well with water containing contaminant levels exceeding the drinking water standards of s. NR 812.06 , except turbidity, may be either steel or thermoplastic pipe and shall meet the specifications of s. NR 812.17 and have a nominal diameter at least 2 inches smaller than the nominal diameter of the permanent well casing pipe or the diameter of the drillhole. If the liner pipe has threaded and coupled joints the outside diameter of the couplings shall be 2 inches smaller in diameter than the nominal diameter of the original well casing pipe or the diameter of the drillhole.

(a) The liner pipe shall have a set of at least 3 centering guides at least every 40 feet and they shall be installed so as to not restrict the flow of grout sealing material. A minimum of 2 sets of guides shall be provided, one at the top and one at the bottom of the liner.

(b) When the liner pipe does not extend to the bottom of the well, a flange or approved packer shall be provided at the bottom of the liner between the outside of the liner and the inside of the drillhole or the inside of the well casing pipe, or the liner shall rest on backfill material to be later drilled or bailed out.

(c) The liner pipe should extend to the ground surface but shall extend at least to the bottom of the pitless adapter when one is used.

(d) The liner pipe shall be completely sealed in place from the bottom of the liner to the top of the liner with neat cement grout using an approved pressure method according to the grouting requirements of s. NR 812.20 . If the liner pipe is thermoplastic, the cement grout thickness may not exceed 1-1/2 inches. The liner shall be supported until the grout has set.

(e) Sealing a drillhole with neat cement grout or concrete and subsequently drilling through this material may not be used to reconstruct a well with water containing contaminate levels exceeding the drinking water standards of s. NR 812.06 , except turbidity.

(f) Liners may only be used to reconstruct existing wells cased with stove pipe casing if:

1. The stove pipe casing is removed and the drillhole is maintained at full diameter before the liner pipe is set and grouted in place, or

2. The existing stove pipe casing and drillhole is completely clear of obstructions to the depth of liner pipe setting.

(2)   Liners installed for caving or sloughing protection, for a non-health-related water quality problem or for a turbidity problem.

(a) A liner pipe shall be installed when the following conditions exist:

1. A caving or sloughing formation is encountered in drilling or subsequent to well completion and causes interference with the proper functioning of the well or pumping equipment; or

2. The well produces turbid water or pumps sand after unsuccessful attempts at redevelopment.

(b) Liner pipe used only to seal off a caving or sloughing zone, for a non-health-related water quality problem or to prevent turbid water may be either steel or thermoplastic meeting the requirements of s. NR 812.17 . Steel liner pipe may have a lesser wall thickness than is required in Table V for the diameter of well casing pipe but shall have a wall thickness of at least 0.216 inches. When thermoplastic pipe is used and is sealed in place with cement grout, the grout thickness may not exceed 1-1/2 inches.

(c) Liner pipe installed for the reasons cited in par. (b) may have the largest practical diameter allowing installation in the well.

(d) The liner pipe shall extend at least 10 feet above the static water level or packers shall be installed far enough above and below the caving zone to prevent further entrance of material into the well. When the liner pipe does not extend to the bottom of the well, the liner pipe shall be supported on the bottom and top with a pipe flange or packer installed between the outside of the liner and the inside of the drillhole.

(e) Sealing a drillhole with neat cement grout or concrete grout and subsequently drilling through the hardened grout may be used to reconstruct a well with water containing contaminant levels not exceeding the drinking water standards of s. NR 812.06 for non-health-related water quality problems or for turbidity problems.

History: Cr. Register, January, 1991, No. 421 , eff. 2-1-91; am. (intro), (1) (d), (2) (b), (c) and (e), Register, September, 1994, No. 465 , eff. 10-1-94.