Colorado has 63 counties, with 51 classified as EPA Zone 1 (highest risk). With an average radon level of 8.97 pCi/L, Colorado state testing data reveals significantly elevated risks across multiple counties. Testing is highly recommended.
Colorado is the 8th most expansive state and the 22nd most populous. Most Colorado counties have shown moderate to excessive levels of radon.
The state of Colorado also has a very commendable Radon program, with a wide variety of resources and information available on the official site.
Explore radon data organized by metro region, including average levels, hotspot cities, and local mitigation professionals.
Cities with the most user-submitted radon test data, ranked by number of submissions.
| City | Avg User Radon Level | Submissions |
|---|---|---|
| Fairplay | 12.00 pCi/L | 9 |
| Crested Butte | 8.56 pCi/L | 9 |
| Denver | 6.22 pCi/L | 9 |
| Montrose | 9.25 pCi/L | 8 |
| Gunnison | 7.38 pCi/L | 8 |
| Buena Vista | 12.57 pCi/L | 7 |
| Pueblo | 10.67 pCi/L | 6 |
| Grand Junction | 8.17 pCi/L | 6 |
| Bayfield | 6.00 pCi/L | 6 |
| Canon City | 10.80 pCi/L | 5 |
| Aurora | 7.40 pCi/L | 5 |
| Windsor | 7.00 pCi/L | 5 |
| Telluride | 6.80 pCi/L | 5 |
| Parker | 5.40 pCi/L | 5 |
| Salida | 15.50 pCi/L | 4 |
| Johnstown | 9.50 pCi/L | 4 |
| Granby | 9.00 pCi/L | 4 |
| Longmont | 8.00 pCi/L | 4 |
| Edwards | 6.75 pCi/L | 4 |
| Mancos | 6.00 pCi/L | 4 |
All 63 Colorado counties with their EPA radon zone classification and user-submitted average radon levels.
Browse radon data for individual cities across Colorado. Each city page includes user-submitted radon levels, local contractors, and mitigation resources.