Jefferson County, WV: EPA's radon zone, explained

EPA's own radon map rates Jefferson County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Nationally that's the 91st percentile for radon potential — Jefferson County outranks 91% of every county EPA has rated.

Where Jefferson County sits nationally

Jefferson County, West Virginia is home to about 61,264 people across 209.289 square miles. Population density there runs about 293 people per square mile. By population, Jefferson County is the 270th largest of every county sharing its EPA zone — the 75th percentile by population within that zone. Jefferson County falls in EPA Radon Region 3, one of 245 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Jefferson County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. EPA's guidance doesn't change because of a Zone 1 label: test the house. What changes is the reason to not put it off in Jefferson County specifically.

Next steps for a home in Jefferson County

For a Jefferson 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 West Virginia'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. RADONZONE-10OFF at checkout knocks 10% off.

Where Jefferson County's figures come from

Jefferson County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.