Mercer County, WV radon potential

EPA's own radon map rates Mercer County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Rank it against the rest of the country and Mercer County lands in the 91st percentile for radon potential.

Mercer County by the numbers

Mercer County, West Virginia is home to about 57,524 people across 418.962 square miles. Averaged across its land area, Mercer County runs about 137 people per square mile. Within its own EPA zone, Mercer County is bigger by population than 73% of the counties that share it. EPA's geology-based Region 3 groups Mercer County with 244 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Mercer County

Where the national indoor average runs about 1.3 pCi/L, Mercer County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. 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 Mercer County will test well under the action level, and EPA's guidance is to test regardless of zone.

Testing and mitigation in Mercer 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 West Virginia's state radon program

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

Where Mercer County's figures come from

Mercer 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.