Yamhill County, OR: EPA's radon zone, explained

Yamhill 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. Rank it against the rest of the country and Yamhill County lands in the 60th percentile for radon potential.

Where Yamhill County sits nationally

Yamhill County, Oregon is home to about 110,886 people across 715.938 square miles. Averaged across its land area, Yamhill County runs about 155 people per square mile. By population, Yamhill County is the 181st largest of every county sharing its EPA zone — the 83rd percentile by population within that zone. Yamhill County falls in EPA Radon Region 10, one of 142 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Neither at the 4 pCi/L action level nor down at the roughly 1.3 pCi/L national indoor norm, Yamhill County's Zone 2 prediction lands in the gap between the two. Nothing about a Zone 2 label lowers the case for testing in Yamhill County — EPA recommends it in every zone, moderate included.

Next steps for a home in Yamhill County

For a Yamhill 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 Oregon's state radon program

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

Where Yamhill County's figures come from

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