Section NR 811.18 - Special requirements for sandstone wellsThe 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:
(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.(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.(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.(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.Wis. Admin. Code Department of Natural Resources NR 811.18
CR 09-073: cr. Register November 2010 No. 659, eff. 12-1-10.