Well water in Elkhorn, Wisconsin
In Elkhorn, 1% of 327 private wells tested between 2011 and 2023 had nitrate above the Wisconsin enforcement standard (10 mg/L), according to the UWSP Well Water Quality Viewer.
327 private wells tested 2011 to 2023 in state summaries; 1 individual samples from 1 wells, 1983. Data refreshed September 9, 2026.
What homeowner tests found
Wisconsin Well Water Quality Viewer samples: private wells tested and reported to the state, 2011 to 2023. Shares are against the level the state applies to each contaminant, named in the last column; several are stricter than EPA.
| Contaminant | Wells tested | Above state level | Median | 95th pct | Highest | State level | |
|---|---|---|---|---|---|---|---|
| Nitrate | 327 | 1% | 0.686 | 6.78 | 13.9 | 10 mg/L |
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What this means
Among homeowners in Elkhorn who sent a sample to the state lab, the health-based limits most often exceeded were nitrate (1% of 327 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 Elkhorn
- Volatile organic compounds (VOCs)24 leaking underground storage tank sites on record locally.
- Nitrate1% of 327 local wells tested were above the Wisconsin enforcement standard.
- Coliform bacteriaRecommended for every private well, every year.
Contamination sources on record in Elkhorn
Wisconsin DNR records 24 leaking underground storage tank sites in Elkhorn, among 68 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.
- 24
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 1
- lined landfill or transfer facility
- 43
- other remediation projects
Get your Elkhorn water tested at home
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Common questions
How often should I test a private well in Elkhorn?
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.
Sources
- USGS Water Quality Portal: 2 samples in Elkhorn. 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 1 contaminants in Elkhorn, up to 327 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: 68 regulated sites located in Elkhorn. 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.