Tillamook County, OR Radon Zone Data

Tillamook County, OR radon potential

Tillamook County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Rank it against the rest of the country and Tillamook County lands in the 17th percentile for radon potential.

Tillamook County by the numbers

Tillamook County, Oregon is home to about 27,264 people across 1,103.185 square miles. That works out to roughly 25 people per square mile. Within its own EPA zone, Tillamook County is bigger by population than 50% of the counties that share it. EPA's geology-based Region 10 groups Tillamook County with 141 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Tillamook County

At Zone 3, Tillamook County's predicted county average is under the national indoor average (~1.3 pCi/L) and well below EPA's 4 pCi/L action level — outdoor air nationally runs about 0.4 pCi/L for comparison. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Tillamook County testing above the action level often enough that skipping a test isn't the safe assumption.

Testing and mitigation in Tillamook County

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Oregon's state radon program

For Tillamook County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Tillamook 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 Tillamook County's figures come from

The methodology guide shows exactly which EPA and Census sources feed Tillamook County's numbers. Whatever zone Tillamook County carries, the zone explainer covers what it does and doesn't tell you about any one house.