Radon in Utah
About 4 in 10 homes tested in Utah were at or above the EPA action level of 4 pCi/L.
- Below 2 pCi/L: 30%
- 2 to 4 pCi/L: 28%
- 4 pCi/L or more: 42%
The EPA puts 7 of Utah's 29 counties in Zone 1, its highest radon category, 22 in Zone 2 and 0 in Zone 3.
Every county in Utah
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 |
|---|---|---|---|---|
| Beaver County | 3 tests | – | – | 2 |
| Garfield County | 3 tests | – | – | 2 |
| San Juan County | 11 tests | – | – | 2 |
| Box Elder County | 64% | 5.8 pCi/L | 2 | |
| Wasatch County | 62% | 6.0 pCi/L | 2 | |
| Sanpete County | 61% | 5.7 pCi/L | 1 | |
| Juab County | 61% | 6.2 pCi/L | 2 | |
| Morgan County | 61% | 4.7 pCi/L | 2 | |
| Cache County | 57% | 4.7 pCi/L | 2 | |
| Uintah County | 55% | 4.2 pCi/L | 1 | |
| Sevier County | 55% | 4.7 pCi/L | 1 | |
| Utah County | 48% | 3.8 pCi/L | 2 | |
| Duchesne County | 47% | 3.9 pCi/L | 1 | |
| Tooele County | 45% | 3.5 pCi/L | 2 | |
| Wayne County | 2 tests | – | – | 2 |
| Salt Lake County | 39% | 3.1 pCi/L | 2 | |
| Kane County | 11 tests | – | – | 2 |
| Weber County | 36% | 2.6 pCi/L | 2 | |
| Davis County | 34% | 2.7 pCi/L | 2 | |
| Summit County | 33% | 2.6 pCi/L | 2 | |
| Carbon County | 32% | 2.7 pCi/L | 1 | |
| Iron County | 22% | 2.3 pCi/L | 2 | |
| Grand County | 15% | 1.4 pCi/L | 1 | |
| Washington County | 15% | 1.8 pCi/L | 2 | |
| Millard County | 11 tests | – | – | 2 |
| Daggett County | 1 tests | – | – | 2 |
| Emery County | 1 tests | – | – | 2 |
| Rich County | 2 tests | – | – | 2 |
| Piute County | No data | – | – | 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.