Well water in Eau Claire County, Wisconsin
In Eau Claire County, 5% of 1,184 private wells tested between 1988 and 2025 had nitrate above the Wisconsin enforcement standard (10 mg/L), according to the UWSP Well Water Quality Viewer.
1,184 private wells tested 2014 to 2024 in state summaries; 4 individual samples from 4 wells, 1957 to 2014. Data refreshed September 9, 2026.
What homeowner tests found
Wisconsin Well Water Quality Viewer samples: private wells tested and reported to the state, 2014 to 2024. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA. County and state figures combine the town summaries, weighted by wells tested; medians are not combined.
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What this means
Among homeowners in Eau Claire County who sent a sample to the state lab, the health-based limits most often exceeded were nitrate (5% of 1,184 wells). These are ordinary wells tested by their owners, so the shares are the best available picture of a typical well here, with one caveat: people test more often when they suspect a problem.
What to test for in Eau Claire County
- Volatile organic compounds (VOCs)99 leaking underground storage tank sites on record locally.
- Sodium7% of 14 local wells tested were above the EPA advisory level.
- Nitrate5% of 1,184 local wells tested were above the Wisconsin enforcement standard.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 940 pCi/L.
- FluorideDetected in 100% of local samples.
- ChlorideDetected in 100% of local samples.
- ManganeseDetected in 75% of local samples.
Contamination sources on record in Eau Claire County
Wisconsin DNR records 99 leaking underground storage tank sites in Eau Claire County, among 389 regulated sites in total. Groundwater does not follow property lines, so a well within a few hundred feet of one of these is worth testing for what that site could release.
- 99
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 22
- lined landfills and transfer facilities
- 268
- other remediation projects
Treatment that fits the local profile
- Nitrate
- Point-of-use reverse osmosis; Anion exchange; Distillation
- Sodium
- Point-of-use reverse osmosis; Distillation
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Manganese
- Oxidizing filter (greensand, birm) whole-house; Water softener (low levels); Point-of-use reverse osmosis
- Chloride
- Point-of-use reverse osmosis; Distillation
Get your Eau Claire County water tested at home
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Common questions
How high is radon in well water in Eau Claire County?
The median radon level across 1 public samples in Eau Claire County was 940 pCi/L, with a high of 940 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Eau Claire County?
Test for bacteria and nitrate every year. Test once for arsenic, uranium, radon, fluoride, manganese and PFAS, then again every three to five years or after any change in taste, color, or plumbing.
Towns in Eau Claire County
- Bridge Creek4% nitrate
- Brunswick2% nitrate
- Lincoln4% nitrate
- Ludington2% nitrate
- Pleasant Valley7% nitrate
- Seymour2% nitrate
- Union9% nitrate
- Washington3% nitrate
11 towns have fewer than 30 public samples and are included in the Eau Claire County totals above rather than shown separately: Altoona, Augusta, Clear Creek, Drammen, Eau Claire, Fairchild, Fairchild village, Fall Creek village, Lake Hallie village, Otter Creek, Wilson.
Sources
- USGS Water Quality Portal: 12 samples in Eau Claire County. Data from the Water Quality Portal, a service of USGS, EPA and USDA; groundwater samples collected by USGS and cooperators. Retrieved September 3, 2026.
- Wisconsin Well Water Quality Viewer samples: summaries for 9 contaminants in Eau Claire County, up to 1,184 wells each. Private well samples compiled by the UWSP Center for Watershed Science and Education from the DNR Groundwater Retrieval Network, DATCP surveys, the UWSP Water and Environmental Analysis Lab and county health programs, published in the Wisconsin Well Water Quality Viewer with Wisconsin DHS. Samples are located to the town, village or city they fall in; one result per well and parameter (the latest) so repeat samples do not double count; wells without a state well number are keyed by location. Shares are against Wisconsin NR 140 enforcement standards (arsenic 10 ug/L, nitrate 10 mg/L as N, manganese 300 ug/L, lead 15 ug/L, copper 1.3 mg/L) and the iron and chloride secondary levels. Many samples were submitted by homeowners with a reason to test, so shares can run above a random survey. Retrieved September 9, 2026.
- Wisconsin DNR regulated sites: 389 regulated sites located in Eau Claire County. Open and closed remediation activities (BRRTS, including leaking underground storage tanks and spills) and landfill and waste sites from the Wisconsin Department of Natural Resources. Retrieved September 9, 2026.
Non-detects count as samples and are treated as zero when computing medians. Exactly at the limit counts as not above it. A sample belongs to the town containing the well's reported coordinates.