Manganese in Wisconsin well water
In Wisconsin, 4% of 7,925 private wells tested between 1999 and 2025 had manganese above the Wisconsin enforcement standard (300 ug/L), according to the UWSP Well Water Quality Viewer.
Manganese stains fixtures and laundry above 50 ug/L. EPA's health advisory is 300 ug/L; infants are the most sensitive, and newer research links elevated manganese to neurological effects in children. It is one of the most common private well problems in New England.
Check your manganese number
Type the value from your lab report. It is compared to the Wisconsin enforcement standard and the EPA limit, the same way the full interpretation does it.
Getting it fixed
Book a free in-home water test with a licensed local company, or see the treatment guide for what removes manganese.
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 | Wells tested | Above state level | Highest | |
|---|---|---|---|---|
| Price | 33 | 18% | 4,398 ug/L | |
| Lincoln | 37 | 14% | 2,564 ug/L | |
| Burnett | 304 | 13% | 4,507 ug/L | |
| Barron | 360 | 11% | 9,964 ug/L | |
| Chippewa | 545 | 10% | 7,170 ug/L | |
| Vilas | 78 | 10% | 2,210 ug/L | |
| Taylor | 215 | 10% | 1,651 ug/L | |
| Wood | 53 | 9% | 5,171 ug/L | |
| Washburn | 33 | 9% | 1,493 ug/L | |
| Sawyer | 72 | 8% | 2,062 ug/L | |
| Oneida | 102 | 8% | 1,326 ug/L | |
| Langlade | 40 | 8% | 1,041 ug/L | |
| Marathon | 816 | 6% | 2,155 ug/L | |
| Juneau | 62 | 5% | 809 ug/L | |
| Shawano | 45 | 4% | 909 ug/L |
Towns with the highest share above the state level
- Eagle Point, Chippewa County23% of 52 wells
- Knowlton, Marathon County14% of 63 wells
- Round Lake, Sawyer County13% of 32 wells
- Hull, Portage County10% of 49 wells
- Lafayette, Chippewa County9% of 45 wells
- Woodmohr, Chippewa County7% of 30 wells
- Excelsior, Sauk County6% of 31 wells
- Mosinee, Marathon County6% of 48 wells
- Anson, Chippewa County6% of 34 wells
- Waterloo, Jefferson County4% of 49 wells
- Farmington, Jefferson County4% of 53 wells
- Stettin, Marathon County3% of 36 wells
- Hebron, Jefferson County3% of 36 wells
- Palmyra, Jefferson County3% of 40 wells
- St. Joseph, St. Croix County2% of 42 wells
- Aztalan, Jefferson County2% of 47 wells
- Watertown, Jefferson County2% of 49 wells
- Chilton, Calumet County2% of 51 wells
- Oakland, Jefferson County1% of 78 wells
- Ixonia, Jefferson County0% of 90 wells
- Koshkonong, Jefferson County0% of 86 wells
- Lake Mills, Jefferson County0% of 65 wells
- Concord, Jefferson County0% of 54 wells
- Sullivan, Jefferson County0% of 54 wells
- New Glarus, Green County0% of 54 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.
- Individual samples from the USGS Water Quality Portal and state monitoring, summarized per geography. manganese counts and shares are listed on each county and town page with their sources.