Washington has 39 counties, with 7 classified as EPA Zone 1 (highest risk). With an average radon level of 7.01 pCi/L, Washington state testing data reveals significantly elevated risks across multiple counties. Testing is highly recommended.
Washington is the 18th most expansive state in terms of size and the 13th most populous.
Washington does have an active radon program, dedicated to educating citizens about the risks associated with the deadly gas. You can find more information on Radon, testing and mitigation at the official page.
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 |
|---|---|---|
| Vancouver | 6.56 pCi/L | 9 |
| Kent | 3.60 pCi/L | 5 |
| Seattle | 5.25 pCi/L | 4 |
| Olympia | 5.00 pCi/L | 4 |
| Bellevue | 3.75 pCi/L | 4 |
| Spokane | 11.67 pCi/L | 3 |
| Camas | 8.00 pCi/L | 3 |
| Centralia | 7.00 pCi/L | 3 |
| Bellingham | 4.50 pCi/L | 2 |
| Kirkland | 4.50 pCi/L | 2 |
| Washougal | 8.00 pCi/L | 1 |
| Ridgefield | 5.00 pCi/L | 1 |
| Moses Lake | No submissions | 0 |
All 39 Washington counties with their EPA radon zone classification and user-submitted average radon levels.
Browse radon data for individual cities across Washington. Each city page includes user-submitted radon levels, local contractors, and mitigation resources.