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

EPA places Grant County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Rank it against the rest of the country and Grant County lands in the 76th percentile for radon potential.

Where Grant County sits nationally

Grant County, West Virginia is home to about 10,971 people across 477.373 square miles. Population density there runs about 23 people per square mile. By population, Grant County is the 743rd largest of every county sharing its EPA zone — the 30th percentile by population within that zone. EPA's geology-based Region 3 groups Grant County with 244 other counties nationally sharing its underlying rock and soil profile.

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 Grant County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Grant County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Grant County

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

Where Grant County's figures come from

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