Maryland has 20 counties, with 8 classified as EPA Zone 1 (highest risk). With an average radon level of 8.66 pCi/L, Maryland state testing data reveals significantly elevated risks across multiple counties. Testing is highly recommended.
Maryland is the smallest state in terms of size and yet it is one of most populous in the entire US. The state does not have an active radon program.
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 |
|---|---|---|
| Frederick | 8.29 pCi/L | 7 |
| Potomac | 9.00 pCi/L | 6 |
| Hagerstown | 8.67 pCi/L | 6 |
| Westminster | 14.50 pCi/L | 4 |
| Baltimore | 7.00 pCi/L | 4 |
| Annapolis | 4.25 pCi/L | 4 |
| Upper Marlboro | 15.00 pCi/L | 3 |
| Edgewater | 12.67 pCi/L | 3 |
| Bowie | 9.00 pCi/L | 3 |
| Clarksburg | 8.00 pCi/L | 3 |
| Gambrills | 6.00 pCi/L | 3 |
| Elkton | 5.33 pCi/L | 3 |
| Silver Spring | 4.33 pCi/L | 3 |
| Chesapeake Beach | 14.00 pCi/L | 2 |
| Cumberland | 9.00 pCi/L | 2 |
| Frostburg | 9.00 pCi/L | 2 |
| Owings | 5.50 pCi/L | 2 |
| Huntingtown | 4.50 pCi/L | 2 |
| Mc Henry | 20.00 pCi/L | 1 |
| Mount Airy | 20.00 pCi/L | 1 |
All 20 Maryland counties with their EPA radon zone classification and user-submitted average radon levels.
Browse radon data for individual cities across Maryland. Each city page includes user-submitted radon levels, local contractors, and mitigation resources.