Radon in Wyoming
About 4 in 10 homes tested in Wyoming were at or above the EPA action level of 4 pCi/L.
- Below 2 pCi/L: 26%
- 2 to 4 pCi/L: 31%
- 4 pCi/L or more: 43%
The EPA puts 21 of Wyoming's 23 counties in Zone 1, its highest radon category, 2 in Zone 2 and 0 in Zone 3.
Every county in Wyoming
Sorted by the share of homes tested at or above 4 pCi/L. Select a county for local details and costs.
| County | Homes tested | At or above 4 | Median | EPA zone |
|---|---|---|---|---|
| Sheridan County | 70% | 5.8 pCi/L | 1 | |
| Lincoln County | 68% | 7.8 pCi/L | 1 | |
| Weston County | 66% | 6.3 pCi/L | 2 | |
| Converse County | 62% | 4.8 pCi/L | 1 | |
| Crook County | 59% | 5.1 pCi/L | 1 | |
| Hot Springs County | 56% | 4.2 pCi/L | 1 | |
| Fremont County | 56% | 4.7 pCi/L | 1 | |
| Natrona County | 56% | 4.3 pCi/L | 1 | |
| Sublette County | 50% | 4.0 pCi/L | 1 | |
| Sweetwater County | 50% | 3.9 pCi/L | 1 | |
| Teton County | 45% | 3.4 pCi/L | 1 | |
| Campbell County | 44% | 3.5 pCi/L | 1 | |
| Park County | 43% | 3.4 pCi/L | 1 | |
| Big Horn County | 42% | 3.5 pCi/L | 1 | |
| Goshen County | 42% | 3.3 pCi/L | 1 | |
| Carbon County | 41% | 3.0 pCi/L | 1 | |
| Washakie County | 39% | 3.2 pCi/L | 1 | |
| Johnson County | 35% | 3.1 pCi/L | 1 | |
| Albany County | 28% | 2.7 pCi/L | 1 | |
| Platte County | 27% | 2.4 pCi/L | 2 | |
| Laramie County | 26% | 2.5 pCi/L | 1 | |
| Niobrara County | 6 tests | – | – | 1 |
| Uinta County | 25% | 2.2 pCi/L | 1 |
"–" means fewer than 20 tests or no lab data, too few for a reliable figure.
Sources
- EPA Map of Radon Zones (public domain).
- CDC Environmental Public Health Tracking Network, radon tests from labs, 2008–2017. Pre-mitigation tests only.
Last updated October 2026. How we calculate these numbers.