Is Dewey County, OK a radon risk area?

EPA places Dewey County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. That puts Dewey County in the 2nd percentile nationally for radon potential — higher than 2% of the counties EPA has rated.

Where Dewey County sits nationally

About 4,268 people live in Dewey County, Oklahoma, spread over 999.628 square miles. Population density there runs about 4 people per square mile. Rank 959 by population within its EPA zone puts Dewey County at the 7th percentile among zone peers. Geologically, Dewey County is grouped into EPA Region 6 alongside 502 other counties that share its rock and soil setting.

What this actually means for a house in Dewey County

Dewey County's predicted average sits below the national indoor average of about 1.3 pCi/L, well under EPA's 4 pCi/L action level. A Zone 3 rating means Dewey County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

Testing and mitigation in Dewey County

Nothing about Dewey County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Oklahoma's state radon program

Dewey County's test kit answers today; a Airthings radon monitor keeps answering for Dewey 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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Dewey County carries, the zone explainer covers what it does and doesn't tell you about any one house.