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Well filling and sealing

Abandoned or unused wells pose a great threat to the safety and quality of groundwater drinking water supplies. An unused well provides a direct path for contaminants and pollutants to the underground aquifers that supply working wells.

Wells must be properly filled when they are removed from service. If your property is served by a municipal drinking water system, a municipal well filling and sealing ordinance may also require you to obtain a permit or permanently fill and seal any private wells on your property. Drillholes and exploratory boreholes must also be properly filled and sealed when they are no longer in use.

As of June 1, 2008, only licensed well drillers and pump installers can fill and seal wells under Wisconsin law.

A well or drillhole is considered to be permanently abandoned when it has been completely filled and sealed by a licensed driller or pump installer using materials and methods as prescribed in s. NR 812.26, Wis. Adm. Code [exit DNR]. This generally means that the pump and any piping inside of the casing have been removed and the well or drillhole has been filled from bottom to top with proper filling materials, such as cement grout, concrete grout, concrete, a clay/sand slurry mix or, in some cases, bentonite chips.