Is Pend Oreille County, WA a radon risk area?

EPA places Pend Oreille County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Nationally, Pend Oreille County ranks higher in radon potential than 78% of rated counties (the 78th percentile).

Where Pend Oreille County sits nationally

About 14,332 people live in Pend Oreille County, Washington, spread over 1,400.245 square miles. Population density there runs about 10 people per square mile. Rank 678 by population within its EPA zone puts Pend Oreille County at the 36th percentile among zone peers. EPA's geology-based Region 10 groups Pend Oreille County with 141 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Where the national indoor average runs about 1.3 pCi/L, Pend Oreille County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. That doesn't mean every Pend Oreille County house tests high — a zone is a county-wide prediction, never a single-home reading — but it's a reason to test sooner rather than let it wait.

Testing and mitigation in Pend Oreille County

Nothing about Pend Oreille 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

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

The methodology guide shows exactly which EPA and Census sources feed Pend Oreille County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.