EPA Zone Data 2026
NH Radon Levels
View EPA radon zone classifications for every county in NH. Select your county to see detailed risk data, testing recommendations, and mitigation cost estimates.
1
Zone 1
High Risk
High Risk
9
Zone 2
Moderate
Moderate
0
Zone 3
Low Risk
Low Risk
Belknap
Zone 2
Carroll
Zone 1
Cheshire
Zone 2
Coos
Zone 2
Grafton
Zone 2
Hillsborough
Zone 2
Merrimack
Zone 2
Rockingham
Zone 2
Strafford
Zone 2
Sullivan
Zone 2
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