Radon Levels in Idaho
44 counties — 19 high risk, 20 moderate, 5 low risk
Idaho Radon Zone Map
Counties colored by EPA radon zone. Red = Zone 1, Orange = Zone 2, Green = Zone 3.
Highest-Risk Counties
BenewahZone 1 — High
BlaineZone 1 — High
BoiseZone 1 — High
Bonner41.7% above action level
BoundaryZone 1 — High
ButteZone 1 — High
CamasZone 1 — High
ClarkZone 1 — High
ClearwaterZone 1 — High
CusterZone 1 — High
ElmoreZone 1 — High
FremontZone 1 — High
+7 more
Check Your Idaho ZIP Code
All 44 Counties — By Radon Risk
Sources: EPA Map of Radon Zones, CDC Environmental Health Tracking Network
Frequently Asked Questions
How many counties in Idaho have high radon risk?
Idaho has 19 counties classified as EPA Zone 1 (high radon risk), 20 as Zone 2 (moderate), and 5 as Zone 3 (low risk).
Is radon a problem in Idaho?
Idaho has 19 high-risk counties where elevated radon is likely. The EPA recommends all homes in Idaho be tested for radon, regardless of which zone they're in.
How do I check radon levels for my Idaho 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.