Total coliform in Wisconsin well water
In Wisconsin, 10% of 11,282 private wells tested between 1990 and 2025 had total coliform above the Wisconsin limit (any detection) (n/a MPN/100mL), according to the UWSP Well Water Quality Viewer.
Coliform bacteria live in soil and on plants as well as in sewage. Their presence means surface water or soil is getting into the well through the cap, casing or a nearby defect. Most coliforms are harmless, but they mean disease-causing organisms can get in the same way.
Check your total coliform number
Type the value from your lab report. It is compared to the EPA limit, the same way the full interpretation does it.
Test your Wisconsin well for total coliform
Certified lab analysis of your own tap water, bottles and prepaid return shipping included. The Essential well panel covers arsenic, uranium, nitrate, lead, copper, manganese, iron, sodium and bacteria; radon and PFAS are add-ons.
Order the Tap Score well water test kit, from $209Already tested? Upload the report
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Systems that remove total coliform
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Some links below are affiliate links. If you buy through one, the merchant pays us a commission at no extra cost to you. It does not change which products we list or what the data says.
For total coliform
Aquasana Rhino Well Water with UV
whole-house, at the point of entry, about $2,871
Whole-house system built for wells: sediment pre-filter, KDF and carbon, and a UV lamp rated to kill 99.99% of bacteria and viruses. It does not remove arsenic, nitrate, uranium or radon.
Rather have it installed and sized for your well? Book a free in-home water test with a licensed local company.
Where to get a well tested for total coliform in Wisconsin: certified labs, state programs and prices.
By county, from homeowner tests
Share of private wells above the state guidance level (n/a MPN/100mL) in tests homeowners sent to the state lab, 2000 to 2025.
Towns with the highest share above the state level
- Red River, Kewaunee County27% of 52 wells
- Eau Pleine, Portage County24% of 33 wells
- Beaver Dam, Dodge County23% of 60 wells
- Carson, Portage County22% of 41 wells
- La Valle, Sauk County22% of 32 wells
- Trenton, Washington County19% of 31 wells
- Lima, Sheboygan County17% of 35 wells
- Exeter, Green County17% of 30 wells
- Brothertown, Calumet County16% of 55 wells
- Lebanon, Waupaca County16% of 43 wells
- Matteson, Waupaca County16% of 37 wells
- Linwood, Portage County16% of 31 wells
- Stockbridge, Calumet County16% of 77 wells
- Harrison village, Calumet County15% of 40 wells
- Adams, Adams County14% of 35 wells
- Plover, Portage County14% of 65 wells
- Dewey, Portage County14% of 51 wells
- Plymouth, Sheboygan County14% of 37 wells
- St. Joseph, St. Croix County13% of 60 wells
- Rhine, Sheboygan County13% of 38 wells
- Scandinavia, Waupaca County13% of 69 wells
- Lincoln, Kewaunee County13% of 85 wells
- Grand Rapids, Wood County13% of 48 wells
- Trade Lake, Burnett County12% of 33 wells
- Lanark, Portage County12% of 85 wells
Sources
- Wisconsin Well Water Quality Viewer samples: 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.