EPA radon zones
New Hampshire radon map: every county's zone
1 of New Hampshire's 10 counties are EPA radon zone 1 (predicted average above 4 pCi/L), 9 are zone 2 and 0 are zone 3. High readings occur in every zone, so EPA recommends testing every home.
Belknap CountyZone 2
Carroll CountyZone 1
Cheshire CountyZone 2
Coos CountyZone 2
Grafton CountyZone 2
Hillsborough CountyZone 2
Merrimack CountyZone 2
Rockingham CountyZone 2
Strafford CountyZone 2
Sullivan CountyZone 2
How much does radon mitigation cost?
Most single-family systems cost $800 to $2,500 installed, depending on foundation type and how many suction points are needed. A follow-up test confirms the system works.
What do the zones mean?
EPA radon zones describe counties, not houses. Zone 1 counties have a predicted average indoor level above 4 picocuries per liter (pCi/L), Zone 2 between 2 and 4, Zone 3 below 2. Homes with high levels are found in every zone, which is why EPA recommends that every home be tested, and fixed at 4 pCi/L or above.
Source: EPA Map of Radon Zones.