Free testing, with limits
Colorado tests private wells for PFAS for free, but not for anything else. Check which tests it includes before you count on it for uranium.
Colorado's private well pageUranium in Colorado well water, by county
Uranium is widespread, over the limit in 15% or more of tested wells, in 8 of the 13 Colorado counties with 10 or more tested wells. A county's share tells you how likely a problem is nearby. Only a test of your own well tells you what's in it.
How Colorado compares with the rest of the country
Across Colorado, about 2 in 10 tested wells had uranium over the EPA limit of 30 µg/L (125 of 598). Across all tested wells in the US it's about 1 in 22. So uranium turns up in Colorado wells about 5 times as often as in the country as a whole, and a test is worth adding even if your county isn't on the list below.
Why it matters: Drinking it for years can harm your kidneys and raises the risk of cancer.
Uranium comes out of the rock and sediment the wells draw from.
Uranium in tested wells, county by county
Share of each county's tested wells with at least one result over the EPA limit of 30 µg/L. Counties need 10 or more tested wells to be listed. Widespread means 15% or more, worth checking 5 to 15%, rare under 5%.
| County | Wells tested | Wells over the limit | Level |
|---|---|---|---|
| Montrose County | 51 | Widespread | |
| Otero County | 17 | Widespread | |
| Weld County | 22 | Widespread | |
| Arapahoe County | 67 | Widespread | |
| Elbert County | 29 | Widespread | |
| Adams County | 36 | Widespread | |
| Pueblo County | 18 | Widespread | |
| Douglas County | 31 | Widespread | |
| Montezuma County | 11 | Worth checking | |
| Park County | 84 | Rare | |
| El Paso County | 68 | Rare | |
| Rio Blanco County | 26 | Rare | |
| Lake County | 10 | Rare |
31 more Colorado counties have 1 to 9 tested wells for uranium, too few to rate.
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Where to get your well tested for uranium in Colorado
A lab Colorado certifies
Ask for uranium by name. Results from a certified lab count for a home sale or a loan.
Labs certified by ColoradoA mail-in kit
Fill the bottles at your kitchen tap and mail them back. We mark the kits that include uranium.
Compare kitsKeep reading about wells in Colorado
- Well water testing in Colorado: how to get tested and what turns up statewide
- Uranium in well water: where it comes from, what it does and how to remove it
- Nitrate in Colorado wells, by county
- Arsenic in Colorado wells, by county
- Manganese in Colorado wells, by county
- Lead in Colorado wells, by county
Questions people ask about uranium in Colorado
Is there uranium in Colorado well water?
Uranium is widespread, over the limit in 15% or more of tested wells, in 8 of the 13 Colorado counties with 10 or more tested wells. Across Colorado, about 2 in 10 tested wells had uranium over the EPA limit of 30 µg/L (125 of 598). Across all tested wells in the US it's about 1 in 22. So uranium turns up in Colorado wells about 5 times as often as in the country as a whole, and a test is worth adding even if your county isn't on the list below.
Where can I get my well tested for uranium in Colorado?
Colorado tests private wells for PFAS for free, but not for anything else. If that doesn't cover you, use a lab certified by Colorado for drinking water, or a mail-in kit that includes uranium from a certified lab.
See Colorado's list of certified labs, or compare mail-in kits.
Where these numbers come from
- Lab tests: Water Quality Portal (USGS and EPA), well samples since 2000. A well counts as over if any of its tests was over the EPA limit of 30 µg/L. Wells tested for studies and monitoring, not a random sample of homes.
- Likely overstated: our own check of who tested the wells, when and where. How we check.
- State programs and links: Department of Public Health and Environment.