What EPA's radon map says about Davis County

EPA places Davis County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Davis County in the 64th percentile nationally for radon potential — higher than 64% of the counties EPA has rated.

Where Davis County sits nationally

About 378,470 people live in Davis County, Utah, spread over 324.76 square miles. Population density there runs about 1,165 people per square mile. Among counties sharing Davis County's EPA zone, it outranks 94% of them by population. Geologically, Davis County is grouped into EPA Region 8 alongside 290 other counties that share its rock and soil setting.

Zone vs. an actual test

Davis County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A county-wide moderate average, like Davis County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in Davis County

Mitigation cost doesn't depend on Davis County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Utah's state radon program

Davis County's test kit answers today; a Airthings radon monitor keeps answering for Davis County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

Davis County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.