Is Benton County, WA a radon risk area?

Benton County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. That puts Benton County in the 62nd percentile nationally for radon potential — higher than 62% of the counties EPA has rated.

Benton County by the numbers

About 218,190 people live in Benton County, Washington, spread over 1,700.128 square miles. Population density there runs about 128 people per square mile. Rank 112 by population within its EPA zone puts Benton County at the 89th percentile among zone peers. Geologically, Benton County is grouped into EPA Region 10 alongside 141 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

Benton County's Zone 2 prediction clears the 1.3 pCi/L national indoor average without reaching EPA's own 4 pCi/L point for recommending a fix. A county-wide moderate average, like Benton 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 Benton County

Nothing about Benton 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

Benton County's test kit answers today; a Airthings radon monitor keeps answering for Benton 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. Whatever zone Benton County carries, the zone explainer covers what it does and doesn't tell you about any one house.