Radon Levels in Maine

16 counties — 12 high risk, 4 moderate, 0 low risk

12
4
Zone 1 High (75.0%) Zone 2 Moderate (25.0%) Zone 3 Low (0.0%)

Maine Radon Zone Map

Counties colored by EPA radon zone. Red = Zone 1, Orange = Zone 2, Green = Zone 3.

Highest-Risk Counties

Androscoggin52.6% above action level
Aroostook50% above action level
Cumberland46.2% above action level
FranklinZone 1 — High
Hancock66.7% above action level
Kennebec42.3% above action level
Lincoln44.4% above action level
Oxford53.3% above action level
Penobscot62.5% above action level
PiscataquisZone 1 — High
Somerset40% above action level
York50% above action level

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All 16 Counties — By Radon Risk

CountyEPA ZoneTests% Above 4 pCi/L
Androscoggin High 19 52.6%
Aroostook High 16 50%
Cumberland High 52 46.2%
Franklin High 8 —
Hancock High 9 66.7%
Kennebec High 26 42.3%
Lincoln High 9 44.4%
Oxford High 15 53.3%
Penobscot High 24 62.5%
Piscataquis High 5 —
Somerset High 10 40%
York High 46 50%
Knox Moderate 8 62.5%
Sagadahoc Moderate 5 —
Waldo Moderate 8 75%
Washington Moderate 6 100%

Sources: EPA Map of Radon Zones, CDC Environmental Health Tracking Network

Frequently Asked Questions

How many counties in Maine have high radon risk?

Maine has 12 counties classified as EPA Zone 1 (high radon risk), 4 as Zone 2 (moderate), and 0 as Zone 3 (low risk).

Is radon a problem in Maine?

Maine has 12 high-risk counties where elevated radon is likely. The EPA recommends all homes in Maine be tested for radon, regardless of which zone they're in.

How do I check radon levels for my Maine address?

Enter your ZIP code in the search box above to see your county's EPA radon zone and available testing data. For your specific home's radon level, you'll need a radon test kit.