In order for communities to plan for the future, it is essential that both the quantity and quality of groundwater be protected. Wisconsin law requires that by January 1, 2010

Groundwater in about 10 percent of wells open to Quaternary glacial and shallow bedrock aquifers in southeastern Wisconsin has arsenic concentrations greater than the U.S. Environmental Protection Agency’s standard of 10 μg/l.

Groundwater use in southeastern Wisconsin has resulted in more than 400 feet of drawdown in the deep sandstone aquifer since pumping begin in the 1860’s.

In Wisconsin the widespread use of the herbicide atrazine has led to the presence of atrazine and it's metabolites in some groundwaters. One of the metabolites, diaminoatrazine, is of particular interest because it is reported to pose a greater health threat (to those drinking the water) than the other metabolites.

Guidance for disinfection of domestic wells in arsenic-sensitive areas of Wisconsin calls for a treatment at 20 percent of the chlorine strength and 10 percent of the contact time recommended for non-arsenic impacted wells.

Ninety eight groundwater samples from water utilities from around the state of Wisconsin were analyzed for uranium activity (U-234, U-235, and U-238), thorium activity (Th-228, Th-230, Th-232), radium activity (Ra-226 and Ra-228), polonium-210 activity (Po-210)