Clarion County, PA radon potential

EPA's own radon map rates Clarion County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 87th percentile for radon potential — Clarion County outranks 87% of every county EPA has rated.

Where Clarion County sits nationally

Clarion County, Pennsylvania is home to about 36,855 people across 600.836 square miles. That works out to roughly 61 people per square mile. Within its own EPA zone, Clarion County is bigger by population than 62% of the counties that share it. EPA's geology-based Region 3 groups Clarion County with 244 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, Clarion County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. That doesn't mean every Clarion 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.

Next steps for a home in Clarion 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 Pennsylvania's state radon program

For Clarion County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Clarion 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 Clarion 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.