Well water in Sheboygan County, Wisconsin
In Sheboygan County, 10% of 305 private wells tested between 1993 and 2025 had total coliform above the Wisconsin limit (any detection), according to the UWSP Well Water Quality Viewer.
984 private wells tested 1999 to 2025 in state summaries; 9 individual samples from 9 wells, 1964 to 2013. Data refreshed September 9, 2026.
What homeowner tests found
Wisconsin Well Water Quality Viewer samples: private wells tested and reported to the state, 1999 to 2025. 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.
Get the free Sheboygan County well report
One email with the numbers above, what they mean for a home in Sheboygan County, exactly which tests to order, and what treatment fits the local profile. No spam, unsubscribe in one click.
What this means
Among homeowners in Sheboygan County who sent a sample to the state lab, the health-based limits most often exceeded were total coliform (10% of 305 wells), arsenic (7% of 220 wells), and copper (2% of 139 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.
Iron and sodium exceed the state's advisory level in a sizable share of wells; these are mostly a taste, staining or diet issue rather than a toxicity one.
What to test for in Sheboygan County
- Volatile organic compounds (VOCs)202 leaking underground storage tank sites on record locally.
- Iron41% of 66 local wells tested were above the Wisconsin nuisance level.
- Sodium38% of 71 local wells tested were above the EPA advisory level.
- Total coliform10% of 305 local wells tested were above the Wisconsin limit (any detection).
- Arsenic7% of 220 local wells tested were above the Wisconsin enforcement standard.
- Copper2% of 139 local wells tested were above the Wisconsin enforcement standard.
- Nitrate1% of 984 local wells tested were above the Wisconsin enforcement standard.
- Manganese<1% of 139 local wells tested were above the Wisconsin enforcement standard.
- Lead<1% of 140 local wells tested were above the Wisconsin enforcement standard.
Contamination sources on record in Sheboygan County
Wisconsin DNR records 202 leaking underground storage tank sites in Sheboygan County, among 751 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.
- 202
- leaking underground storage tank sitesGasoline and heating oil that leaked from tanks move through groundwater as benzene, MTBE and other volatile organic compounds.
- 63
- lined landfills and transfer facilities
- 486
- other remediation projects
Treatment that fits the local profile
- Total coliform
- Inspect and repair the well cap and casing, then shock chlorinate and retest; UV disinfection whole-house; Chlorination system
- Arsenic
- Point-of-use reverse osmosis; Adsorptive media (iron-based) whole-house; Anion exchange
- Iron
- Oxidizing filter whole-house; Water softener (low levels); Aeration plus filtration
- Sodium
- Point-of-use reverse osmosis; Distillation
- Fluoride
- Point-of-use reverse osmosis; Activated alumina; Distillation
- Copper
- Neutralizing filter to raise pH; Point-of-use reverse osmosis
Get your Sheboygan 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 Sheboygan County.
Common questions
How high is radon in well water in Sheboygan County?
The median radon level across 1 public samples in Sheboygan County was 98 pCi/L, with a high of 98 pCi/L. New Hampshire recommends treatment above 2,000 pCi/L.
How often should I test a private well in Sheboygan 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 Sheboygan County
- Greenbush3% nitrate
- Herman0% nitrate
- Holland0% nitrate
- Howards Grove village0% nitrate
- Lima17% total coliform
- Lyndon2% nitrate
- Plymouth14% total coliform
- Rhine13% total coliform
- Scott0% nitrate
- Sheboygan0% nitrate
- Sheboygan Falls0% nitrate
- Sherman0% nitrate
- Wilson8% total coliform
15 towns have fewer than 30 public samples and are included in the Sheboygan County totals above rather than shown separately: Adell village, Cascade village, Cedar Grove village, Elkhart Lake village, Glenbeulah village, Kohler village, Mitchell, Mosel, Oostburg village, Plymouth, Random Lake village, Russell, Sheboygan, Sheboygan Falls, Waldo village.
Sources
- USGS Water Quality Portal: 27 samples in Sheboygan 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 Sheboygan County, up to 984 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: 751 regulated sites located in Sheboygan 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.