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

EPA's own radon map rates Kittitas County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Nationally that's the 55th percentile for radon potential — Kittitas County outranks 55% of every county EPA has rated.

Where Kittitas County sits nationally

Kittitas County, Washington is home to about 48,172 people across 2,297.291 square miles. Averaged across its land area, Kittitas County runs about 21 people per square mile. By population, Kittitas County is the 348th largest of every county sharing its EPA zone — the 66th percentile by population within that zone. Geologically, Kittitas County is grouped into EPA Region 10 alongside 141 other counties that share its rock and soil setting.

What this actually means for a house in Kittitas County

Kittitas County's Zone 2 prediction clears the 1.3 pCi/L national indoor average without reaching EPA's own 4 pCi/L point for recommending a fix. Kittitas County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Testing and mitigation in Kittitas County

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

Where Kittitas County's figures come from

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