Free or low-cost state testing
DPHHS offers free well water testing to prospective or licensed childcare facilities.
Department of Environmental Quality: private well testingGetting your well water tested in Montana
Montana has free or low-cost well testing. Across the state, the ones worth testing for are manganese, arsenic, radon, uranium and nitrate, plus bacteria every year.
About 393,000 people in Montana get their water from a private well, about 1 in 3 residents.
Three ways to get tested, cheapest first.
A lab Montana certifies
The state's list of labs certified for drinking water. Many sell bottles you pick up or get by mail, and their results count for a home sale or loan.
Labs certified by MontanaA mail-in kit
Order online, fill the bottles at your kitchen tap and get results by email in about a week. Full well tests run about $210 to $220.
Compare kits for MontanaWhat turns up in Montana wells.
Share of tested wells over the limit, from lab tests the USGS, EPA and state agencies collected since 2000. Your own well needs its own test.
Manganese34%582 of 1,720Arsenic19%131 of 693Radon18%31 of 168Uranium9%28 of 324Nitrate7%44 of 588Fluoride5%40 of 775Lead4%28 of 677
GermsTest every year, whatever the chart says
Coliform bacteria29%20 of 69StainsNot a health risk
Iron stains32%347 of 1,072
Rare: under 5%Worth checking: 5 to 15%Widespread: 15%+
Lab results: Water Quality Portal (USGS and EPA)
Where it shows up most
- Nitrate shows up most in Valley County (about 1 in 3 wells), Roosevelt County (about 2 in 10 wells).
- Arsenic shows up most in Silver Bow County (about 5 in 10 wells), Lewis and Clark County (about 1 in 7 wells).
- Uranium shows up most in Jefferson County (about 1 in 9 wells).
Find your county.
5 counties have a full report with local test results and well depths.
No full report for that county yet. The statewide results above still apply, and so do the three ways to get tested.
Every county in Montana: people on wells and typical depth
| County | People on private wells | Share of residents | Typical well depth |
|---|---|---|---|
| Flathead County | 47,064 | 45% | 193 ft |
| Missoula County | 37,878 | 32% | 100 ft |
| Gallatin County | 34,439 | 29% | 82 ft |
| Ravalli County | 33,358 | 76% | 76 ft |
| Lewis and Clark County | 27,963 | 39% | 111 ft |
| Yellowstone County | 26,528 | 16% | 38 ft |
| Lake County | 15,964 | 51% | 180 ft |
| Cascade County | 13,274 | 16% | 142 ft |
| Lincoln County | 12,621 | 64% | 151 ft |
| Jefferson County | 8,420 | 70% | 195 ft |
| Silver Bow County | 8,053 | 23% | 116 ft |
| Park County | 7,602 | 44% | 120 ft |
| Sanders County | 7,456 | 60% | 170 ft |
| Carbon County | 7,004 | 67% | 58 ft |
| Big Horn County | 6,422 | 49% | 50 ft |
| Stillwater County | 6,195 | 69% | 60 ft |
| Madison County | 5,911 | 69% | 105 ft |
| Hill County | 5,204 | 32% | 111 ft |
| Roosevelt County | 5,020 | 47% | 79 ft |
| Beaverhead County | 4,980 | 53% | 80 ft |
| Richland County | 4,542 | 40% | 74 ft |
| Fergus County | 4,422 | 39% | 140 ft |
| Broadwater County | 4,273 | 63% | 150 ft |
| Glacier County | 3,824 | 28% | 101 ft |
| Rosebud County | 3,238 | 39% | 140 ft |
| Valley County | 3,202 | 42% | 75 ft |
| Teton County | 3,191 | 51% | 32 ft |
| Blaine County | 3,032 | 43% | 80 ft |
| Custer County | 2,853 | 24% | 220 ft |
| Sheridan County | 2,593 | 73% | 108 ft |
| Deer Lodge County | 2,564 | 27% | 63 ft |
| Chouteau County | 2,548 | 43% | 68 ft |
| Musselshell County | 2,547 | 54% | 220 ft |
| Mineral County | 2,521 | 56% | 122 ft |
| Dawson County | 2,518 | 28% | 100 ft |
| Powell County | 2,238 | 32% | 85 ft |
| Granite County | 2,140 | 65% | 86 ft |
| Sweet Grass County | 1,946 | 53% | 80 ft |
| Pondera County | 1,881 | 32% | 85 ft |
| Phillips County | 1,852 | 44% | 72 ft |
| Judith Basin County | 1,423 | 70% | 90 ft |
| Powder River County | 1,206 | 71% | 241 ft |
| Daniels County | 1,094 | 66% | 76 ft |
| McCone County | 1,081 | 63% | 114 ft |
| Toole County | 1,063 | 21% | 91 ft |
| Carter County | 990 | 70% | 160 ft |
| Fallon County | 965 | 32% | 237 ft |
| Meagher County | 874 | 45% | 110 ft |
| Garfield County | 791 | 67% | 160 ft |
| Wheatland County | 744 | 36% | 100 ft |
| Liberty County | 617 | 31% | 150 ft |
| Golden Valley County | 577 | 70% | 100 ft |
| Treasure County | 507 | 67% | 60 ft |
| Prairie County | 502 | 46% | 154 ft |
| Wibaux County | 498 | 53% | 144 ft |
| Petroleum County | 332 | 67% | 160 ft |
Questions people ask about well water in Montana
Does Montana require private wells to be tested?
Montana doesn't require routine testing of existing private wells. Keeping a well safe is up to the owner, so test for bacteria and nitrate every year.
Where can I get my well water tested in Montana?
DPHHS offers free well water testing to prospective or licensed childcare facilities. Otherwise, use a lab certified by Montana for drinking water. The state's list is linked on this page.
Where these numbers come from
- How many people use wells: EPA estimates from the 2020 Census.
- Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000.
- State programs and links: Department of Environmental Quality.