<p>This report summarizes data on ground-water quality stored in the U.S. Geological Survey's computer system (WATSTORE).
The summary includes water quality data for 2,443 single-aquifer wells, which tap one of the State's three major aquifers
(sand and gravel, Silurian dolomite, and sandstone). Data for dissolved solids, hardness, alkalinity, calcium, magnesium,
sodium, potassium, iron, manganese, sulfate, chloride, fluoride, and nitrate are summarized by aquifer and by county, and
locations of wells for which data are available 1 are shown for each aquifer. Calcium, magnesium, and bicarbonate (the principal
component of alkalinity) are the major dissolved constituents in Wisconsin's ground water. High iron concentrations and hardness
cause ground-water quality problems in much of the State. Statewide ,summaries of trace constituent (selected trace metals;
arsenic, boron, and organic carbon) concentrations show that these constituents impair water quality in only a few isolated
wells.</p>