Radon Levels in New Hampshire
New Hampshire is classified as an EPA Zone 1 state with a high risk for radon. Average indoor radon levels range from 2 to 7 pCi/L, and approximately 38% of New Hampshire homes test above the EPA action level of 4.0 pCi/L.
New Hampshire Radon Summary
High Radon Risk State
New Hampshire is among the higher-risk states for residential radon. The New Hampshire Department of Health strongly recommends that all residents test their homes. If you have not tested your home, consider ordering a test kit or radon detector today.
Key Facts About Radon in New Hampshire
- New Hampshire's granite geology is a significant radon source
- NH has one of the highest percentages of homes above the action level in New England
- The NH DES actively promotes radon testing
- New England stone foundations are common radon entry points
New Hampshire Testing Requirements & Recommendations
New Hampshire requires radon testing disclosure in real estate transactions. Strongly recommended for all homes.
NH has certified radon mitigation professionals throughout the state.
Major Cities in New Hampshire
Radon levels can vary significantly within New Hampshire 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 New Hampshire 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 New Hampshire. 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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