State radon data hub
Utah radon levels, county by county
28 Utah counties have published radon test data. Ranked worst-first below — the median county sees 40% of home tests reach the EPA action level of 4 pCi/L. Deep-dive pages (data + geology + housing stock) exist for 2 counties so far; more ship as coverage expands.
Costs, licensing, and how to read a quote: the Utah mitigation cost guide. Instant county lookup: radon by ZIP.
| # | County | % tests ≥ 4 pCi/L | Tests (10-yr) | EPA zone |
|---|---|---|---|---|
| 1 | Beaver | 100% | 3 | 2 |
| 2 | Garfield | 100% | 3 | 2 |
| 3 | San Juan | 66.7% | 11 | 2 |
| 4 | Box Elder | 64.3% | 338 | 2 |
| 5 | Wasatch | 61.7% | 373 | 2 |
| 6 | Sanpete | 61.3% | 56 | 1 |
| 7 | Juab | 61% | 31 | 2 |
| 8 | Morgan | 60.6% | 69 | 2 |
| 9 | Cache | 56.8% | 1,002 | 2 |
| 10 | Uintah | 55.3% | 60 | 1 |
| 11 | Sevier | 54.6% | 91 | 1 |
| 12 | Utah | 48% | 4,620 | 2 |
| 13 | Duchesne | 47.4% | 27 | 1 |
| 14 | Tooele | 45.4% | 371 | 2 |
| 15 | Wayne | 40% | 2 | 2 |
| 16 | Salt Lake | 39.1% | 10,449 | 2 |
| 17 | Kane | 38.9% | 11 | 2 |
| 18 | Weber | 36.2% | 870 | 2 |
| 19 | Davis | 33.7% | 2,100 | 2 |
| 20 | Summit | 33.1% | 595 | 2 |
| 21 | Carbon | 32.3% | 52 | 1 |
| 22 | Iron | 22.4% | 84 | 2 |
| 23 | Grand | 14.8% | 39 | 1 |
| 24 | Washington | 14.8% | 178 | 2 |
| 25 | Millard | 11.1% | 11 | 2 |
| 26 | Daggett | 0% | 1 | 2 |
| 27 | Emery | 0% | 1 | 2 |
| 28 | Rich | 0% | 2 | 2 |
Source: CDC EPHT (labs), 2008–2017; county rank by share of tests at or above 4 pCi/L (counties with too few reported tests are excluded — absence of data is not absence of radon). Zones: EPA Map of Radon Zones. Piute County has no published CDC test data and is omitted. Full sourcing on the methodology page.