Well water in Forest County, Wisconsin
In Forest County, 4% of 106 private wells tested between 2003 and 2025 had arsenic above the Wisconsin enforcement standard (10 ug/L), according to the UWSP Well Water Quality Viewer.
619 private wells tested 2005 to 2023 in state summaries; 31 individual samples from 19 wells, 1977 to 2024. Data refreshed September 9, 2026.
What homeowner tests found
Wisconsin Well Water Quality Viewer samples: private wells tested and reported to the state, 2005 to 2023. 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.
What individual samples found
Each row summarizes every public sample for that contaminant inside Forest County. Above limit means above the EPA maximum contaminant level; where EPA has no enforceable limit, the row shows a health guideline or nuisance level instead.
| Contaminant | Samples | Detected | Above limit | Median | Highest | Limit | |
|---|---|---|---|---|---|---|---|
| Uranium 1979 to 2024 | 31 | 74% | 0% | 0.024 | 29 | 30 ug/L EPA limit | |
| Radium (226 + 228) 2003 to 2013 | 10 | 80% | 0% | 0.092 | 0.88 | 5 pCi/L EPA limit | |
| Radon 1982 to 2003 | 16 | 100% | no limit | 433 | 4,600 | 2,000 pCi/L health guideline |
Sampled fewer than 10 times, too few to summarize: Arsenic (6), Lead (3), Nitrate (2), Copper (2), Iron (3), Sodium (3).
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What this means
Among homeowners in Forest County who sent a sample to the state lab, the health-based limits most often exceeded were arsenic (4% of 106 wells) and nitrate (<1% of 619 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 Forest County
- Volatile organic compounds (VOCs)20 leaking underground storage tank sites on record locally.
- Arsenic4% of 106 local wells tested were above the Wisconsin enforcement standard.
- Nitrate<1% of 619 local wells tested were above the Wisconsin enforcement standard.
- Coliform bacteriaRecommended for every private well, every year.
- RadonMedian local reading is 433 pCi/L.
- CopperDetected in 100% of local samples.
- IronDetected in 100% of local samples.
Contamination sources on record in Forest County
Wisconsin DNR records 20 leaking underground storage tank sites in Forest County, among 125 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.
- 20
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 36
- lined landfills and transfer facilities
- 69
- other remediation projects
Treatment that fits the local profile
- Copper
- Neutralizing filter to raise pH; Point-of-use reverse osmosis
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
Get your Forest County water tested at home
A licensed local water treatment company tests your tap water in your home, walks you through the numbers, and quotes treatment only if something needs fixing. Free, about 30 minutes, no obligation. Tell us what you need and we match you with a company that serves Forest County.
Common questions
Is there arsenic in well water in Forest County?
Arsenic was detected in 67% of 6 public well samples in Forest County, and 0% were above the EPA limit of 10 ug/L. Arsenic has no taste or smell; a lab test is the only way to know your level.
How high is radon in well water in Forest County?
The median radon level across 16 public samples in Forest County was 433 pCi/L, with a high of 4,600 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Forest 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 Forest County
- Argonne0% nitrate
- Armstrong Creek0% nitrate
- Crandon2% nitrate
- Hiles0% nitrate
- Laona<1% nitrate
- Lincoln0% nitrate
- Nashville1% nitrate
- Wabeno0% nitrate
7 towns have fewer than 30 public samples and are included in the Forest County totals above rather than shown separately: Alvin, Blackwell, Caswell, Crandon, Freedom, Popple River, Ross.
Sources
- USGS Water Quality Portal: 76 samples in Forest 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 10 contaminants in Forest County, up to 619 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: 125 regulated sites located in Forest 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.