Eau Claire County, Wisconsin: drinking water report. Eau Claire County in west-central Wisconsin has a population of about 106,000.
Eau Claire County in west-central Wisconsin has a population of about 106,000. The city of Eau Claire draws water from 16 deep wells tapping the Wonewoc-Mt. Simon sandstone aquifer, producing naturally cold, clear groundwater. The county sits at the confluence of the Chippewa and Eau Claire Rivers, and while the city does not use river water for drinking supply, the rivers influence the shallow aquifer zones that some rural properties tap.
PFAS contamination from the Eau Claire municipal airport has emerged as the county's most pressing water quality issue. According to the Wisconsin DNR's 2024 PFAS investigation, firefighting foam used at the airport has contaminated shallow groundwater in the surrounding area, with PFOS detected at concentrations up to 80 ppt in private wells near the airport – above Wisconsin's recommended groundwater enforcement standard of 20 ppt.
The city's deep municipal wells draw from a different aquifer zone than the affected shallow wells, and testing has not shown PFAS contamination in the municipal supply. A 2024 Wisconsin DHS assessment confirmed that the city's treated water tested below detection limits for all regulated PFAS compounds. However, manganese in some of the city's wells requires treatment, and one well has been taken offline due to elevated manganese levels.
The distinction between deep municipal wells and shallow private wells matters in Eau Claire County. City water draws from a protected deep aquifer. Private wells near the airport are vulnerable to the PFAS plume.
Check your water to see data for your specific area. If you are on a private well near the airport, independent PFAS testing is a priority. For PFAS, reverse osmosis is the most effective household treatment. Our water filter guide explains the options. Pull your detailed report for any available historical data, and visit our Wisconsin page for statewide context.