Skamania County, WA: EPA's radon zone, explained

EPA's own radon map rates Skamania County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally, Skamania County ranks higher in radon potential than 77% of rated counties (the 77th percentile).

Where Skamania County sits nationally

Skamania County, Washington is home to about 12,660 people across 1,658.268 square miles. Population density there runs about 8 people per square mile. By population, Skamania County is the 707th largest of every county sharing its EPA zone — the 34th percentile by population within that zone. Skamania County falls in EPA Radon Region 10, one of 142 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Skamania 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. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Skamania County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Skamania County

For a Skamania County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Washington's state radon program

For Skamania County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Skamania County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where Skamania County's figures come from

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.