Is Stevens County, WA a radon risk area?
Stevens County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. That puts Stevens County in the 90th percentile nationally for radon potential — higher than 90% of the counties EPA has rated.
Where Stevens County sits nationally
About 49,015 people live in Stevens County, Washington, spread over 2,477.103 square miles. Averaged across its land area, Stevens County runs about 20 people per square mile. Rank 319 by population within its EPA zone puts Stevens County at the 70th percentile among zone peers. Stevens County falls in EPA Radon Region 10, one of 142 counties nationally EPA assigns to that same geologic province.
What this actually means for a house in Stevens County
Stevens County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. Being in Zone 1 raises the odds Stevens County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.
Next steps for a home in Stevens County
Nothing about Stevens 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 Washington's state radon program
Stevens County's test kit answers today; a Airthings radon monitor keeps answering for Stevens County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Code RADONZONE-10OFF takes 10% off at checkout.
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. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.