Radon Levels in New Jersey

21 counties — 7 high risk, 11 moderate, 3 low risk

7
11
3
Zone 1 High (33.3%) Zone 2 Moderate (52.4%) Zone 3 Low (14.3%)

New Jersey Radon Zone Map

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

Highest-Risk Counties

Hunterdon37% above action level
Mercer24.3% above action level
Monmouth31.5% above action level
Morris32.3% above action level
Somerset24.6% above action level
Sussex38.7% above action level
Warren45.5% above action level

Check Your New Jersey ZIP Code

All 21 Counties — By Radon Risk

CountyEPA ZoneTests% Above 4 pCi/L
Hunterdon High 27 37%
Mercer High 70 24.3%
Monmouth High 124 31.5%
Morris High 99 32.3%
Somerset High 57 24.6%
Sussex High 31 38.7%
Warren High 22 45.5%
Bergen Moderate 181 21.5%
Burlington Moderate 93 26.9%
Camden Moderate 102 29.4%
Cumberland Moderate 29 31%
Essex Moderate 126 25.4%
Gloucester Moderate 57 36.8%
Hudson Moderate 94 22.3%
Middlesex Moderate 130 30%
Passaic Moderate 80 32.5%
Salem Moderate 15 —
Union Moderate 84 27.4%
Atlantic Low 52 30.8%
Cape May Low 24 41.7%
Ocean Low 157 37.6%

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

Frequently Asked Questions

How many counties in New Jersey have high radon risk?

New Jersey has 7 counties classified as EPA Zone 1 (high radon risk), 11 as Zone 2 (moderate), and 3 as Zone 3 (low risk).

Is radon a problem in New Jersey?

New Jersey has 7 high-risk counties where elevated radon is likely. The EPA recommends all homes in New Jersey be tested for radon, regardless of which zone they're in.

How do I check radon levels for my New Jersey 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.