Jefferson County, PA radon potential

Jefferson 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. That puts Jefferson County in the 54th percentile nationally for radon potential — higher than 54% of the counties EPA has rated.

Jefferson County by the numbers

Jefferson County, Pennsylvania is home to about 43,367 people across 652.44 square miles. Population density there runs about 66 people per square mile. Within its own EPA zone, Jefferson County is bigger by population than 63% of the counties that share it. Geologically, Jefferson County is grouped into EPA Region 3 alongside 244 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

EPA's Zone 2 rating for Jefferson County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. A county-wide moderate average, like Jefferson County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Testing and mitigation in Jefferson 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 Jefferson County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Jefferson 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 Jefferson 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. Whatever zone Jefferson County carries, the zone explainer covers what it does and doesn't tell you about any one house.