Iron in Wisconsin well water
In Wisconsin, 18% of 6,371 private wells tested between 1994 and 2025 had iron above the Wisconsin nuisance level (300 ug/L), according to the UWSP Well Water Quality Viewer.
Iron is a nuisance rather than a health hazard: rust stains, metallic taste, and clogged fixtures above 300 ug/L. It often occurs with manganese and can feed iron bacteria that foul plumbing.
Check your iron number
Type the value from your lab report. It is compared to the Wisconsin nuisance level and the EPA limit, the same way the full interpretation does it.
Test your Wisconsin well for iron
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 iron
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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 iron
Iron and manganese oxidizing filter
whole-house, at the point of entry, about $1,800
Air-injection or greensand media; fixes staining at the source.
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 iron in Wisconsin: certified labs, state programs and prices.
By county, from homeowner tests
Share of private wells above the state guidance level (300 ug/L) in tests homeowners sent to the state lab, 1999 to 2025.
| County | Above state level | Wells tested | Highest |
|---|---|---|---|
| Price | 33 | 15,370 ug/L | |
| Sheboygan | 66 | 7,410 ug/L | |
| Jefferson | 684 | 61,640 ug/L | |
| Kewaunee | 45 | 2,712 ug/L | |
| Manitowoc | 47 | 24,814 ug/L | |
| Fond du Lac | 118 | 6,612 ug/L | |
| Taylor | 108 | 37,556 ug/L | |
| Oneida | 79 | 18,540 ug/L | |
| Vilas | 68 | 10,731 ug/L | |
| Clark | 50 | 17,088 ug/L | |
| Shawano | 32 | 14,000 ug/L | |
| Washington | 36 | 9,717 ug/L | |
| Wood | 38 | 5,837 ug/L | |
| Pepin | 93 | 7,570 ug/L | |
| Dodge | 112 | 9,326 ug/L |
Towns with the highest share above the state level
- Watertown, Jefferson County59% of 37 wells
- Palmyra, Jefferson County55% of 31 wells
- Ixonia, Jefferson County54% of 70 wells
- Farmington, Jefferson County49% of 45 wells
- Jefferson, Jefferson County39% of 36 wells
- Hebron, Jefferson County38% of 32 wells
- Sullivan, Jefferson County35% of 43 wells
- Lake Mills, Jefferson County34% of 50 wells
- Concord, Jefferson County33% of 45 wells
- Hull, Portage County33% of 39 wells
- Mosinee, Marathon County26% of 34 wells
- Aztalan, Jefferson County26% of 38 wells
- Oakland, Jefferson County24% of 58 wells
- Knowlton, Marathon County24% of 50 wells
- St. Joseph, St. Croix County20% of 30 wells
- Eagle Point, Chippewa County18% of 50 wells
- Koshkonong, Jefferson County18% of 68 wells
- Stockton, Portage County15% of 33 wells
- Waterloo, Jefferson County14% of 42 wells
- Anson, Chippewa County13% of 30 wells
- Cooks Valley, Chippewa County13% of 39 wells
- Lafayette, Chippewa County10% of 41 wells
- Chilton, Calumet County9% of 33 wells
- Sevastopol, Door County7% of 43 wells
- Dekorra, Columbia County5% of 42 wells
By county, from individual samples
Public monitoring samples against the EPA limit; counties with at least 30 samples.
| County | Above EPA limit | Samples | Detected | Median | Highest |
|---|---|---|---|---|---|
| Dunn | no limit | 57 | 100% | 460 | 12,000 ug/L |
| Jackson | no limit | 34 | 100% | 315 | 6,400 ug/L |
| Kenosha | no limit | 54 | 100% | 400 | 16,000 ug/L |
| Milwaukee | no limit | 164 | 100% | 520 | 7,600 ug/L |
| Door | no limit | 54 | 100% | 100 | 10,000 ug/L |
| Buffalo | no limit | 34 | 100% | 965 | 12,000 ug/L |
| Wood | no limit | 175 | 100% | 390 | 37,000 ug/L |
| Kewaunee | no limit | 36 | 100% | 320 | 2,000 ug/L |
| Walworth | no limit | 182 | 99% | 870 | 10,000 ug/L |
| La Crosse | no limit | 121 | 99% | 220 | 7,200 ug/L |
| Rock | no limit | 104 | 99% | 40 | 7,700 ug/L |
| Trempealeau | no limit | 94 | 99% | 2,600 | 61,000 ug/L |
| Menominee | no limit | 89 | 99% | 140 | 6,000 ug/L |
| Green | no limit | 67 | 99% | 100 | 1,400 ug/L |
| Grant | no limit | 134 | 99% | 200 | 16,000 ug/L |
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.
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. iron counts and shares are listed on each county and town page with their sources.