Wis. Stat. § 293.66: Groundwater quality.

(1) For the site of any activity that will take place under a mining or prospecting permit or under another approval related to a mining or prospecting operation, the department shall determine the depth in the Precambrian bedrock below which the groundwater is not reasonably capable of being used or made suitable for human consumption and is not hydrologically connected to other sources of groundwater that are suitable for human consumption. The department shall notify the applicant of its determination before the department issues a draft environmental impact statement.

(2) For an activity regulated under a mining or prospecting permit or another approval related to the mining or prospecting operation, the department may not apply a groundwater enforcement standard at any point that is deeper than the depth identified under sub. (1).