Quick answer
About 1,114,000 people in Minnesota (21.0% of residents) got their water from private wells in 2010, according to USGS estimates. Minnesota Department of Health runs the state’s private well guidance. MDH provides free well test kits (nitrate, arsenic, coliform bacteria/E. coli, lead and manganese) while supplies last to people who rely on a private well in Dodge, Fillmore, Goodhue, Houston, Mower, Olmsted, Wabasha and Winona counties.
- People on private wells
- 1,113,789
- Share of residents
- 21.0%
- Rank among states
- 14th
- Well users modeled above 10 µg/L arsenic
- 9.1%
Where to get your well tested in Minnesota
- Minnesota Department of Health: Well Management Program, the state’s guidance for private well owners.
- Well water testing in Minnesota: what to test for and how to collect a sample.
- Certified laboratories in Minnesota. Use a lab certified for drinking water, so results are reliable.
Free or low-cost testing
MDH provides free well test kits (nitrate, arsenic, coliform bacteria/E. coli, lead and manganese) while supplies last to people who rely on a private well in Dodge, Fillmore, Goodhue, Houston, Mower, Olmsted, Wabasha and Winona counties. (source)
Mail-in lab kits are another option when no local lab is convenient. See well water test kits for what home kits can and can’t tell you.
What to test for
- Every year: total coliform bacteria and nitrate.
- Before buying equipment: pH, hardness, iron, manganese and, if there’s a smell, hydrogen sulfide.
- Based on location: arsenic, uranium and radon, PFAS, and lead in older plumbing.
USGS modeling estimates that about 9.1% of Minnesota’s private well users have water above the 10 µg/L arsenic limit. Arsenic has no taste or smell, so include it in your first test.
Private wells by county
Estimated people relying on private wells in each Minnesota county in 2010, the share of residents that represents, and the modeled share of well users with arsenic above 10 µg/L. These are USGS model estimates (2010 population), not measurements of any well. Arsenic is hidden for counties with fewer than 500 well users.
| County | People on wells | Share | Arsenic >10 µg/L |
|---|---|---|---|
| Anoka County | 51,670 | 15.6% | 2.3% |
| Stearns County | 51,505 | 34.2% | 7.5% |
| St. Louis County | 51,055 | 25.5% | 3.6% |
| Hennepin County | 42,547 | 3.7% | 6.5% |
| Wright County | 38,637 | 31.0% | 7.0% |
| Washington County | 37,741 | 15.8% | 2.9% |
| Crow Wing County | 32,782 | 52.5% | 2.1% |
| Otter Tail County | 32,399 | 56.5% | 14.7% |
| Sherburne County | 30,359 | 34.3% | 4.7% |
| Itasca County | 25,758 | 57.2% | 6.0% |
| Beltrami County | 25,603 | 57.6% | 3.5% |
| Dakota County | 24,787 | 6.2% | 3.3% |
Show all 87 counties
| Chisago County | 24,244 | 45.0% | 3.1% |
| Cass County | 23,752 | 83.1% | 2.9% |
| Olmsted County | 22,318 | 15.5% | 3.0% |
| Isanti County | 21,531 | 56.9% | 3.8% |
| Morrison County | 20,804 | 62.7% | 4.8% |
| Pine County | 20,719 | 69.6% | 5.7% |
| Becker County | 20,638 | 63.5% | 11.4% |
| Scott County | 19,566 | 15.1% | 8.6% |
| Douglas County | 18,914 | 52.5% | 9.8% |
| Carlton County | 17,334 | 49.0% | 3.7% |
| Rice County | 17,162 | 26.8% | 13.1% |
| Todd County | 16,669 | 67.0% | 6.1% |
| Carver County | 16,060 | 17.6% | 23.1% |
| Winona County | 16,028 | 31.1% | 3.1% |
| Hubbard County | 15,919 | 77.9% | 3.3% |
| Goodhue County | 15,615 | 33.8% | 3.5% |
| Mille Lacs County | 14,993 | 57.4% | 5.4% |
| Kandiyohi County | 14,843 | 35.1% | 38.2% |
| Blue Earth County | 13,674 | 21.4% | 26.7% |
| Ramsey County | 13,248 | 2.6% | 3.6% |
| Benton County | 13,044 | 33.9% | 8.0% |
| Aitkin County | 12,915 | 79.7% | 2.9% |
| Kanabec County | 11,856 | 73.0% | 5.4% |
| Meeker County | 11,504 | 49.4% | 44.4% |
| McLeod County | 11,204 | 30.6% | 28.2% |
| Fillmore County | 9,914 | 47.5% | 4.6% |
| Le Sueur County | 9,911 | 35.8% | 26.7% |
| Mower County | 9,556 | 24.4% | 6.1% |
| Clay County | 9,163 | 15.5% | 17.5% |
| Freeborn County | 9,128 | 29.2% | 9.0% |
| Roseau County | 9,060 | 58.0% | 2.5% |
| Wabasha County | 8,926 | 41.2% | 4.0% |
| Polk County | 8,146 | 25.8% | 31.3% |
| Steele County | 7,752 | 21.2% | 12.8% |
| Houston County | 7,196 | 37.8% | 3.5% |
| Nicollet County | 7,181 | 21.9% | 19.0% |
| Wadena County | 6,969 | 50.3% | 4.7% |
| Dodge County | 6,771 | 33.7% | 8.4% |
| Sibley County | 6,729 | 44.2% | 26.8% |
| Pope County | 6,327 | 57.5% | 8.4% |
| Clearwater County | 6,308 | 72.5% | 7.1% |
| Waseca County | 5,772 | 30.2% | 15.3% |
| Brown County | 5,606 | 21.7% | 31.6% |
| Renville County | 5,469 | 34.8% | 32.6% |
| Martin County | 5,270 | 25.3% | 43.1% |
| Redwood County | 4,902 | 30.5% | 39.8% |
| Lyon County | 4,900 | 19.0% | 11.8% |
| Pennington County | 4,478 | 32.1% | 5.7% |
| Murray County | 4,459 | 51.1% | 17.6% |
| Faribault County | 4,404 | 30.3% | 23.3% |
| Nobles County | 4,217 | 19.7% | 8.0% |
| Jackson County | 4,030 | 39.3% | 40.8% |
| Cottonwood County | 4,015 | 34.4% | 31.8% |
| Yellow Medicine County | 4,013 | 38.4% | 18.2% |
| Swift County | 3,941 | 40.3% | 21.1% |
| Lake County | 3,770 | 34.7% | 2.2% |
| Chippewa County | 3,648 | 29.3% | 7.6% |
| Lac qui Parle County | 3,534 | 48.7% | 18.6% |
| Marshall County | 3,512 | 37.2% | 5.0% |
| Koochiching County | 3,266 | 24.5% | 4.5% |
| Watonwan County | 3,091 | 27.6% | 40.6% |
| Mahnomen County | 2,961 | 54.7% | 9.0% |
| Lake of the Woods County | 2,878 | 71.1% | 3.6% |
| Norman County | 2,834 | 41.4% | 9.0% |
| Stevens County | 2,729 | 28.1% | 5.0% |
| Grant County | 2,495 | 41.5% | 16.4% |
| Wilkin County | 2,369 | 36.0% | 10.9% |
| Cook County | 2,311 | 44.7% | 2.3% |
| Red Lake County | 1,943 | 47.5% | 5.6% |
| Rock County | 1,693 | 17.5% | 21.3% |
| Pipestone County | 1,644 | 17.1% | 5.3% |
| Big Stone County | 1,591 | 30.2% | 23.6% |
| Lincoln County | 1,429 | 24.2% | 4.7% |
| Traverse County | 1,280 | 36.0% | 8.8% |
| Kittson County | 901 | 19.8% | 5.4% |
Counties with the highest modeled arsenic share: Meeker County (44.4%), Martin County (43.1%), Jackson County (40.8%), Watonwan County (40.6%), Redwood County (39.8%).
After you get results
Enter your numbers in the test results tool to see what needs treating and in what order. The guide to reading a well water test explains units and limits.
Common questions
Does Minnesota offer free well water testing?
MDH provides free well test kits (nitrate, arsenic, coliform bacteria/E. coli, lead and manganese) while supplies last to people who rely on a private well in Dodge, Fillmore, Goodhue, Houston, Mower, Olmsted, Wabasha and Winona counties.
Who oversees private wells in Minnesota?
Minnesota Department of Health (Well Management Program) publishes guidance for private well owners. Private wells aren’t covered by the federal Safe Drinking Water Act, so testing and treatment are up to the owner.
How many people use private wells in Minnesota?
USGS estimates about 1,114,000 people, or 21.0% of the population in 2010. That ranks 14th of the states covered by the estimate.
What should I test my well for in Minnesota?
Test every year for total coliform bacteria and nitrate, plus pH, hardness, iron and manganese before buying equipment. Arsenic is a known concern in parts of Minnesota, so add it to the first test.
Sources
- Minnesota Department of Health: Well Management Program
- Minnesota Department of Health: well water testing
- Minnesota certified laboratories
- Minnesota free or low-cost testing
- USGS data release: domestic well locations and populations served, 2000 and 2010 (Johnson, Belitz and Lombard, 2019)
- CDC Environmental Public Health Tracking: private well water data (from USGS)