Is Cumberland County, NC a radon risk area?

Cumberland County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Nationally that's the 30th percentile for radon potential — Cumberland County outranks 30% of every county EPA has rated.

How Cumberland County compares

About 338,430 people live in Cumberland County, North Carolina, spread over 652.566 square miles. Population density there runs about 519 people per square mile. Rank 80 by population within its EPA zone puts Cumberland County at the 92nd percentile among zone peers. EPA's geology-based Region 4 groups Cumberland County with 735 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Cumberland County

A Zone 3 county like Cumberland County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. A Zone 3 rating means Cumberland County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

If Cumberland County tests above the action level

Nothing about Cumberland County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find North Carolina's state radon program

Cumberland County's test kit answers today; a Airthings radon monitor keeps answering for Cumberland County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

More on how this number was built

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