Quick answer
About 2,436,000 people in Michigan (24.6% of residents) got their water from private wells in 2010, according to USGS estimates. Michigan Department of Environment, Great Lakes, and Energy runs the state’s private well guidance. We didn’t find a free statewide well testing program in Michigan. Certified labs charge for each test, and some county health departments offer lower-cost bacteria and nitrate tests.
- People on private wells
- 2,436,154
- Share of residents
- 24.6%
- Rank among states
- 1st
- Well users modeled above 10 µg/L arsenic
- 11.4%
Where to get your well tested in Michigan
- Michigan Department of Environment, Great Lakes, and Energy: Water Well Construction Program, the state’s guidance for private well owners.
- Well water testing in Michigan: what to test for and how to collect a sample.
- Certified laboratories in Michigan. Use a lab certified for drinking water, so results are reliable.
Free or low-cost testing
We didn’t find a free statewide program in Michigan. Certified labs charge per test; county health departments sometimes offer lower-cost bacteria and nitrate tests.
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 11.4% of Michigan’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 Michigan 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 |
|---|---|---|---|
| Oakland County | 163,617 | 13.6% | 5.6% |
| Genesee County | 127,543 | 30.0% | 29.5% |
| Kent County | 88,007 | 14.6% | 8.3% |
| Jackson County | 75,004 | 46.8% | 5.2% |
| Livingston County | 73,685 | 40.7% | 7.1% |
| Allegan County | 65,670 | 58.9% | 5.1% |
| Berrien County | 59,649 | 38.0% | 5.5% |
| Kalamazoo County | 55,407 | 22.1% | 2.3% |
| Washtenaw County | 54,169 | 15.7% | 12.1% |
| Calhoun County | 54,148 | 39.8% | 6.5% |
| Muskegon County | 53,169 | 30.9% | 9.3% |
| Lapeer County | 53,117 | 60.1% | 56.6% |
Show all 83 counties
| Ottawa County | 51,549 | 19.5% | 3.5% |
| St. Clair County | 48,413 | 29.7% | 16.0% |
| Van Buren County | 44,080 | 57.8% | 2.4% |
| Montcalm County | 41,904 | 66.2% | 5.3% |
| Monroe County | 41,759 | 27.5% | 6.0% |
| Lenawee County | 40,949 | 41.0% | 8.3% |
| Barry County | 39,303 | 66.4% | 12.3% |
| Ingham County | 39,045 | 13.9% | 6.7% |
| Eaton County | 38,972 | 36.2% | 25.0% |
| Clinton County | 38,435 | 51.0% | 29.9% |
| Tuscola County | 38,185 | 68.5% | 36.4% |
| Saginaw County | 38,157 | 19.1% | 45.5% |
| Cass County | 37,800 | 72.3% | 3.6% |
| Newaygo County | 37,727 | 77.9% | 2.2% |
| Shiawassee County | 37,684 | 53.3% | 38.4% |
| Grand Traverse County | 37,169 | 42.7% | 3.4% |
| Ionia County | 34,969 | 54.7% | 7.3% |
| Macomb County | 34,416 | 4.1% | 9.8% |
| St. Joseph County | 31,336 | 51.1% | 2.1% |
| Midland County | 31,214 | 37.3% | 20.4% |
| Sanilac County | 29,339 | 68.0% | 29.5% |
| Hillsdale County | 29,146 | 62.4% | 7.6% |
| Isabella County | 27,864 | 39.6% | 22.5% |
| Mecosta County | 27,812 | 65.0% | 2.1% |
| Branch County | 26,928 | 59.5% | 4.2% |
| Clare County | 23,025 | 74.5% | 1.9% |
| Gratiot County | 22,890 | 53.9% | 49.8% |
| Cheboygan County | 20,016 | 76.5% | 1.4% |
| Gladwin County | 19,943 | 77.6% | 5.5% |
| Oceana County | 19,678 | 74.1% | 3.7% |
| Huron County | 19,630 | 59.3% | 22.6% |
| Marquette County | 19,180 | 28.6% | 2.2% |
| Emmet County | 19,133 | 58.5% | 2.3% |
| Wexford County | 18,895 | 57.7% | 2.0% |
| Roscommon County | 17,879 | 73.1% | 2.1% |
| Osceola County | 17,764 | 75.5% | 2.0% |
| Bay County | 17,648 | 16.4% | 15.8% |
| Otsego County | 16,865 | 69.8% | 1.5% |
| Ogemaw County | 16,863 | 77.7% | 1.6% |
| Manistee County | 16,393 | 66.3% | 4.6% |
| Delta County | 16,061 | 43.3% | 2.5% |
| Mason County | 16,017 | 55.8% | 3.9% |
| Antrim County | 15,616 | 66.2% | 4.5% |
| Leelanau County | 15,526 | 71.5% | 5.0% |
| Charlevoix County | 14,948 | 57.6% | 4.5% |
| Kalkaska County | 14,737 | 85.9% | 1.6% |
| Iosco County | 14,699 | 56.8% | 2.2% |
| Chippewa County | 14,567 | 37.8% | 2.5% |
| Alpena County | 14,186 | 47.9% | 2.0% |
| Menominee County | 13,019 | 54.2% | 1.4% |
| Benzie County | 12,842 | 73.3% | 4.7% |
| Missaukee County | 12,492 | 84.1% | 1.8% |
| Crawford County | 12,105 | 86.0% | 1.8% |
| Arenac County | 11,577 | 72.8% | 15.2% |
| Lake County | 10,704 | 92.8% | 1.8% |
| Alcona County | 9,630 | 88.0% | 1.8% |
| Presque Isle County | 9,571 | 71.6% | 1.8% |
| Houghton County | 9,230 | 25.2% | 2.0% |
| Montmorency County | 8,938 | 91.5% | 1.6% |
| Oscoda County | 8,014 | 92.8% | 2.1% |
| Wayne County | 7,411 | 0.4% | 3.1% |
| Mackinac County | 6,975 | 62.8% | 2.5% |
| Dickinson County | 6,547 | 25.0% | 2.2% |
| Alger County | 6,418 | 66.9% | 1.6% |
| Schoolcraft County | 4,947 | 58.3% | 1.1% |
| Gogebic County | 4,079 | 24.8% | 3.0% |
| Ontonagon County | 3,574 | 52.7% | 5.2% |
| Luce County | 3,240 | 48.9% | 2.0% |
| Baraga County | 3,232 | 36.5% | 2.4% |
| Iron County | 1,582 | 13.4% | 2.5% |
| Keweenaw County | 528 | 24.5% | 3.0% |
Counties with the highest modeled arsenic share: Lapeer County (56.6%), Gratiot County (49.8%), Saginaw County (45.5%), Shiawassee County (38.4%), Tuscola County (36.4%).
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 Michigan offer free well water testing?
We didn’t find a free statewide well testing program in Michigan. Certified labs charge for each test, and some county health departments offer lower-cost bacteria and nitrate tests.
Who oversees private wells in Michigan?
Michigan Department of Environment, Great Lakes, and Energy (Water Well Construction 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 Michigan?
USGS estimates about 2,436,000 people, or 24.6% of the population in 2010. That ranks 1st of the states covered by the estimate.
What should I test my well for in Michigan?
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 Michigan, so add it to the first test.
Sources
- Michigan Department of Environment, Great Lakes, and Energy: Water Well Construction Program
- Michigan Department of Environment, Great Lakes, and Energy: well water testing
- Michigan certified laboratories
- 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)