Radon Levels in Pennsylvania

67 counties — 49 high risk, 17 moderate, 1 low risk

49
17
1
Zone 1 High (73.1%) Zone 2 Moderate (25.4%) Zone 3 Low (1.5%)

Pennsylvania Radon Zone Map

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

Highest-Risk Counties

Adams40.9% above action level
Allegheny32.5% above action level
Armstrong37.5% above action level
Beaver37.5% above action level
Bedford36.4% above action level
Berks33.3% above action level
Blair37% above action level
Bradford25% above action level
Bucks34.9% above action level
Butler42.1% above action level
CameronZone 1 — High
Carbon35.3% above action level
+37 more

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All 67 Counties — By Radon Risk

CountyEPA ZoneTests% Above 4 pCi/L
Adams High 22 40.9%
Allegheny High 271 32.5%
Armstrong High 16 37.5%
Beaver High 40 37.5%
Bedford High 11 36.4%
Berks High 81 33.3%
Blair High 27 37%
Bradford High 16 25%
Bucks High 126 34.9%
Butler High 38 42.1%
Cameron High — —
Carbon High 17 35.3%
Centre High 22 36.4%
Chester High 84 35.7%
Clarion High 7 —
Clearfield High 15 66.7%
Clinton High 9 —
Columbia High 16 37.5%
Cumberland High 47 40.4%
Dauphin High 49 36.7%
Delaware High 106 32.1%
Franklin High 32 43.8%
Fulton High — —
Huntingdon High 9 —
Indiana High 15 —
Juniata High 6 —
Lackawanna High 46 47.8%
Lancaster High 101 30.7%
Lebanon High 29 31%
Lehigh High 66 33.3%
Luzerne High 75 45.3%
Lycoming High 21 47.6%
Mifflin High 11 45.5%
Monroe High 33 42.4%
Montgomery High 163 31.3%
Montour High 4 —
Northampton High 67 34.3%
Northumberland High 20 50%
Perry High 9 44.4%
Schuylkill High 42 38.1%
Snyder High 8 —
Sullivan High — —
Susquehanna High 10 40%
Tioga High 9 44.4%
Union High 9 —
Venango High 12 50%
Westmoreland High 87 44.8%
Wyoming High 6 —
York High 92 35.9%
Cambria Moderate 34 32.4%
Crawford Moderate 19 42.1%
Elk Moderate 7 57.1%
Erie Moderate 57 40.4%
Fayette Moderate 33 39.4%
Forest Moderate — —
Greene Moderate 7 57.1%
Jefferson Moderate 8 50%
Lawrence Moderate 22 31.8%
McKean Moderate 10 40%
Mercer Moderate 21 57.1%
Pike Moderate 12 41.7%
Potter Moderate — —
Somerset Moderate 20 20%
Warren Moderate 10 60%
Washington Moderate 46 39.1%
Wayne Moderate 12 33.3%
Philadelphia Low 258 34.9%

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

Frequently Asked Questions

How many counties in Pennsylvania have high radon risk?

Pennsylvania has 49 counties classified as EPA Zone 1 (high radon risk), 17 as Zone 2 (moderate), and 1 as Zone 3 (low risk).

Is radon a problem in Pennsylvania?

Pennsylvania has 49 high-risk counties where elevated radon is likely. The EPA recommends all homes in Pennsylvania be tested for radon, regardless of which zone they're in.

How do I check radon levels for my Pennsylvania 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.