EPA Radon Zone Data

Radon Risk by State

The EPA divides the US into three radon zones based on predicted indoor radon levels. Select your state to see your risk level and take action.

High23 states
Moderate21 states
Lower7 states
Click any state to see details
Source: EPA Map of Radon Zones (EPA 402-R-93-071)
Select Your State

Click any state on the map to see its EPA radon zone, average levels, and recommended actions.

All 50 States + DC

Full State Risk Index

StateEPA ZoneRisk LevelAvg Indoor LevelHigh-Risk CountiesAction
COColorado
Zone 1High6.0–10.0 pCi/L42 / 64Test Immediately →
CTConnecticut
Zone 1High4.0–6.0 pCi/L6 / 8Test Immediately →
IDIdaho
Zone 1High4.0–8.0 pCi/L28 / 44Test Immediately →
ILIllinois
Zone 1High4.0–7.0 pCi/L78 / 102Test Immediately →
INIndiana
Zone 1High4.0–6.0 pCi/L72 / 92Test Immediately →
IAIowa
Zone 1High7.0–12.0 pCi/L99 / 99Test Immediately →
KSKansas
Zone 1High4.0–7.0 pCi/L82 / 105Test Immediately →
MEMaine
Zone 1High5.0–9.0 pCi/L14 / 16Test Immediately →
MDMaryland
Zone 1High3.0–6.0 pCi/L12 / 24Test Immediately →
MNMinnesota
Zone 1High4.0–8.0 pCi/L68 / 87Test Immediately →
MOMissouri
Zone 1High4.0–7.0 pCi/L68 / 115Test Immediately →
MTMontana
Zone 1High4.0–8.0 pCi/L38 / 56Test Immediately →
NENebraska
Zone 1High5.0–9.0 pCi/L88 / 93Test Immediately →
NHNew Hampshire
Zone 1High5.0–8.0 pCi/L8 / 10Test Immediately →
NJNew Jersey
Zone 1High3.0–6.0 pCi/L14 / 21Test Immediately →
NDNorth Dakota
Zone 1High5.0–10.0 pCi/L48 / 53Test Immediately →
OHOhio
Zone 1High4.0–7.0 pCi/L72 / 88Test Immediately →
PAPennsylvania
Zone 1High6.0–10.0 pCi/L48 / 67Test Immediately →
SDSouth Dakota
Zone 1High5.0–10.0 pCi/L52 / 66Test Immediately →
UTUtah
Zone 1High4.0–8.0 pCi/L20 / 29Test Immediately →
VTVermont
Zone 1High4.0–7.0 pCi/L12 / 14Test Immediately →
WIWisconsin
Zone 1High4.0–7.0 pCi/L58 / 72Test Immediately →
WYWyoming
Zone 1High4.0–9.0 pCi/L18 / 23Test Immediately →
AKAlaska
Zone 2Moderate2.0–4.0 pCi/L4 / 29Test Recommended →
AZArizona
Zone 2Moderate1.5–3.5 pCi/L3 / 15Test Recommended →
DEDelaware
Zone 2Moderate2.0–4.0 pCi/L1 / 3Test Recommended →
GAGeorgia
Zone 2Moderate1.5–3.5 pCi/L8 / 159Test Recommended →
KYKentucky
Zone 2Moderate2.0–4.0 pCi/L22 / 120Test Recommended →
MAMassachusetts
Zone 2Moderate2.0–4.0 pCi/L4 / 14Test Recommended →
MIMichigan
Zone 2Moderate2.0–4.0 pCi/L18 / 83Test Recommended →
NVNevada
Zone 2Moderate2.0–4.0 pCi/L5 / 17Test Recommended →
NMNew Mexico
Zone 2Moderate2.0–5.0 pCi/L10 / 33Test Recommended →
NYNew York
Zone 2Moderate2.0–5.0 pCi/L22 / 62Test Recommended →
NCNorth Carolina
Zone 2Moderate1.5–4.0 pCi/L14 / 100Test Recommended →
OKOklahoma
Zone 2Moderate2.0–4.0 pCi/L12 / 77Test Recommended →
OROregon
Zone 2Moderate2.0–4.0 pCi/L12 / 36Test Recommended →
RIRhode Island
Zone 2Moderate2.0–4.0 pCi/L3 / 5Test Recommended →
SCSouth Carolina
Zone 2Moderate1.5–3.5 pCi/L8 / 46Test Recommended →
TNTennessee
Zone 2Moderate2.0–4.0 pCi/L18 / 95Test Recommended →
TXTexas
Zone 2Moderate1.0–3.0 pCi/L28 / 254Test Recommended →
VAVirginia
Zone 2Moderate2.0–5.0 pCi/L28 / 133Test Recommended →
WAWashington
Zone 2Moderate2.0–4.0 pCi/L10 / 39Test Recommended →
DCWashington D.C.
Zone 2Moderate2.0–4.0 pCi/L0 / 1Test Recommended →
WVWest Virginia
Zone 2Moderate2.0–5.0 pCi/L18 / 55Test Recommended →
ALAlabama
Zone 3Lower1.0–2.0 pCi/L2 / 67Test Advised →
ARArkansas
Zone 3Lower0.8–2.0 pCi/L1 / 75Test Advised →
CACalifornia
Zone 3Lower0.5–2.0 pCi/L7 / 58Test Advised →
FLFlorida
Zone 3Lower0.5–1.5 pCi/L0 / 67Test Advised →
HIHawaii
Zone 3Lower0.3–1.0 pCi/L0 / 5Test Advised →
LALouisiana
Zone 3Lower0.5–1.5 pCi/L0 / 64Test Advised →
MSMississippi
Zone 3Lower0.5–1.5 pCi/L0 / 82Test Advised →
Source: EPA Map of Radon Zones (EPA 402-R-93-071). Zone designations are based on EPA data and are intended to assist national, state, and local organizations in targeting their resources and to help prioritize radon-resistant new construction requirements. All homes should be tested regardless of zone.

No Zone Is Completely Safe.

Even Zone 3 homes can have dangerous radon levels. The only way to know is to test.

Find a Test Kit Near You
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Disclaimer: This site relies on publicly available state, local, and federal information and statistics sourced from the U.S. EPA, CDC, and the U.S. Surgeon General. Data may change over time. Contact your local government and municipalities for regular updates, current information, and assistance regarding radon testing and mitigation programs in your area.

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Data: EPA · CDC · U.S. Surgeon General