Radon Levels in Maryland
Maryland is classified as an EPA Zone 2 state with a moderate risk for radon. Average indoor radon levels range from 1.5 to 5.5 pCi/L, and approximately 24% of Maryland homes test above the EPA action level of 4.0 pCi/L.
Maryland Radon Summary
Key Facts About Radon in Maryland
- Western Maryland (mountain counties) has EPA Zone 1 levels
- Central Maryland has EPA Zone 2
- Eastern Shore (coastal) has lower risk
- Maryland Department of the Environment provides extensive radon information
Maryland Testing Requirements & Recommendations
Maryland does not require testing but recommends it, particularly in the western counties.
Maryland is home to many radon professionals serving the DC metro area.
Major Cities in Maryland
Radon levels can vary significantly within Maryland depending on local geology. All residents — regardless of city — should test their specific home, as neighborhood-level radon varies independently of broader state and county averages.
What Should Maryland Residents Do?
Test Your Home
Use a short-term charcoal test kit ($15–$25) for an initial reading, or a continuous radon detector for ongoing monitoring. Test in your basement or lowest livable area.
Understand Your Result
If your result is below 2.0 pCi/L: monitor periodically. Between 2.0–4.0 pCi/L: consider mitigation. Above 4.0 pCi/L: the EPA recommends mitigation. Above 8.0 pCi/L: take action promptly.
Hire a Certified Contractor if Needed
Look for NRPP or NRSB-certified radon mitigation contractors in Maryland. Mitigation systems typically cost $800–$2,500 and can reduce radon levels by 50–99%.
Verify with a Follow-Up Test
After mitigation, test again to confirm the system is working. Retest every 2 years, or after significant home renovations.
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