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Radon zones in New Hampshire

The EPA assigns every county in New Hampshire to one of three radon potential zones. 1 are in Zone 1, the highest category, home to about 4% of the state's residents.

10
Counties
1
Zone 1 counties
Predicted average above 4 pCi/L
9
Zone 2 counties
Predicted average 2-4 pCi/L
0
Zone 3 counties
Predicted average below 2 pCi/L

The map

Radon potential across New Hampshire

Every county in New Hampshire, filled by the zone the EPA assigns it. Zones follow geology rather than county lines, so the colour usually changes where the bedrock does, not where the border is.

Zone 1 · 1Zone 2 · 9Zone 3 · 0

Hover a county · click to open it

County by county

All 10 New Hampshire counties

Zone 1 · > 4 pCi/LZone 2 · 2 - 4 pCi/LZone 3 · < 2 pCi/L
CountyZonePopulationCOPDSmokingLung ca. deaths
Carroll County152k7.5%10.7%34.7
Belknap County265k7.5%12.2%36.8
Cheshire County278k7.1%11.9%31.0
Coos County231k9.5%15.2%25.9
Grafton County293k6.4%10.5%29.4
Hillsborough County2427k5.7%10.7%31.2
Merrimack County2157k6.4%10.6%31.5
Rockingham County2321k5.7%9.9%30.4
Strafford County2133k6.0%10.7%38.7
Sullivan County244k8.0%13.0%34.4

Zones from the EPA Map of Radon Zones. COPD and smoking are CDC PLACES model-based estimates of adult prevalence. Lung cancer death rates are age-adjusted deaths per 100,000 per year, 2019-2023, from NCI State Cancer Profiles. A dash means the source does not report a value for that county.

Highest potential

Zone 1 counties in New Hampshire

These 1 counties have a predicted average indoor radon screening level above the EPA action level. The EPA recommends every home in them be tested.

Other states

Radon zones elsewhere