Free or low-cost state testing
CDPHE offers free PFAS testing for private wells through its PFAS Testing and Assistance Program.
Department of Public Health and Environment: private well testingGetting your well water tested in Colorado
Colorado has free or low-cost well testing. Across the state, the ones worth testing for are uranium, manganese, radon, arsenic and nitrate, plus bacteria every year.
About 512,000 people in Colorado get their water from a private well, about 1 in 11 residents.
Three ways to get tested, cheapest first.
A lab Colorado 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 ColoradoA 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 ColoradoWhat turns up in Colorado 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.
Uranium21%125 of 598Manganese19%165 of 855Radon13%21 of 161Arsenic12%83 of 697Nitrate10%103 of 1,004Lead4%23 of 593Fluoride4%37 of 977
GermsTest every year, whatever the chart says
Coliform bacteria20%66 of 325StainsNot a health risk
Iron stains18%159 of 905
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 Adams County (about 1 in 4 wells), Montrose County (about 2 in 10 wells), Arapahoe County (about 2 in 10 wells).
- Arsenic shows up most in Montezuma County (about 5 in 10 wells), Montrose County (about 2 in 10 wells), Lake County (about 1 in 15 wells).
- Uranium shows up most in Montrose County (about 2 in 3 wells), Arapahoe County (about 3 in 10 wells), Elbert County (about 1 in 4 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 Colorado: people on wells and typical depth
| County | People on private wells | Share of residents | Typical well depth |
|---|---|---|---|
| El Paso County | 59,907 | 8% | 320 ft |
| Jefferson County | 45,536 | 8% | 300 ft |
| Weld County | 31,749 | 10% | 210 ft |
| Douglas County | 26,161 | 7% | 385 ft |
| La Plata County | 22,036 | 40% | 160 ft |
| Larimer County | 20,204 | 6% | 280 ft |
| Elbert County | 19,684 | 76% | 378 ft |
| Boulder County | 19,411 | 6% | 204 ft |
| Mesa County | 16,261 | 10% | 184 ft |
| Park County | 15,050 | 87% | 250 ft |
| Adams County | 14,196 | 3% | 340 ft |
| Arapahoe County | 12,988 | 2% | 400 ft |
| Pueblo County | 12,305 | 7% | 60 ft |
| Teller County | 12,184 | 49% | 280 ft |
| Garfield County | 11,275 | 18% | 125 ft |
| Las Animas County | 8,876 | 61% | 167 ft |
| Montezuma County | 8,372 | 32% | 110 ft |
| Montrose County | 8,235 | 19% | 123 ft |
| Chaffee County | 8,176 | 42% | 118 ft |
| Fremont County | 7,527 | 15% | 200 ft |
| Delta County | 7,417 | 24% | 100 ft |
| Morgan County | 6,854 | 24% | 90 ft |
| Grand County | 6,577 | 42% | 200 ft |
| Summit County | 6,371 | 21% | 132 ft |
| Routt County | 6,001 | 24% | 210 ft |
| Eagle County | 5,860 | 11% | 140 ft |
| Logan County | 5,709 | 27% | 95 ft |
| Alamosa County | 5,463 | 33% | 120 ft |
| Rio Grande County | 5,434 | 47% | 106 ft |
| Clear Creek County | 5,352 | 57% | 277 ft |
| Gunnison County | 5,294 | 31% | 75 ft |
| Archuleta County | 4,631 | 35% | 140 ft |
| Gilpin County | 4,566 | 79% | 252 ft |
| Pitkin County | 4,457 | 26% | 102 ft |
| Yuma County | 4,095 | 41% | 220 ft |
| Conejos County | 4,047 | 54% | 80 ft |
| Custer County | 3,777 | 80% | 204 ft |
| Saguache County | 3,272 | 51% | 140 ft |
| Otero County | 3,260 | 17% | 40 ft |
| Moffat County | 3,033 | 23% | 245 ft |
| Bent County | 2,785 | 49% | 180 ft |
| Washington County | 2,483 | 52% | 115 ft |
| Huerfano County | 2,316 | 34% | 180 ft |
| Kit Carson County | 2,173 | 31% | 240 ft |
| Lake County | 2,126 | 29% | 110 ft |
| San Miguel County | 2,033 | 25% | 192 ft |
| Prowers County | 1,952 | 16% | 100 ft |
| Costilla County | 1,835 | 52% | 170 ft |
| Rio Blanco County | 1,566 | 24% | 100 ft |
| Lincoln County | 1,551 | 27% | 60 ft |
| Ouray County | 1,301 | 27% | 217 ft |
| Baca County | 1,252 | 36% | 260 ft |
| Dolores County | 1,181 | 51% | 172 ft |
| Phillips County | 1,140 | 25% | 260 ft |
| Crowley County | 1,058 | 18% | 50 ft |
| Jackson County | 660 | 48% | 104 ft |
| Sedgwick County | 654 | 27% | 105 ft |
| Broomfield County | 601 | under 1% | 362 ft |
| Kiowa County | 581 | 40% | 70 ft |
| Cheyenne County | 577 | 33% | 104 ft |
| Mineral County | 537 | 62% | 84 ft |
| Hinsdale County | 328 | 42% | 91 ft |
| San Juan County | 71 | 10% | 143 ft |
| Denver County | 44 | under 1% | 72 ft |
Questions people ask about well water in Colorado
Does Colorado require private wells to be tested?
Colorado 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 Colorado?
CDPHE offers free PFAS testing for private wells through its PFAS Testing and Assistance Program. Otherwise, use a lab certified by Colorado 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 Public Health and Environment.