Is Adams County, WA a radon risk area?

EPA places Adams 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. Nationally, Adams County ranks higher in radon potential than 47% of rated counties (the 47th percentile).

How Adams County compares

About 21,039 people live in Adams County, Washington, spread over 1,924.989 square miles. Population density there runs about 11 people per square mile. Rank 608 by population within its EPA zone puts Adams County at the 41st percentile among zone peers. EPA's geology-based Region 10 groups Adams County with 141 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

EPA's Zone 2 rating for Adams County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Adams County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Next steps for a home in Adams County

Nothing about Adams 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

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

Adams County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Adams County carries, the zone explainer covers what it does and doesn't tell you about any one house.