What EPA's radon map says about Alleghany County

EPA places Alleghany 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. Alleghany County sits at the 76th percentile nationally for radon potential — above 76 of every 100 rated counties.

Where Alleghany County sits nationally

About 11,379 people live in Alleghany County, North Carolina, spread over 234.835 square miles. Population density there runs about 48 people per square mile. Among counties sharing Alleghany County's EPA zone, it outranks 31% of them by population. EPA's geology-based Region 4 groups Alleghany County with 735 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Alleghany County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. 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 Alleghany County specifically.

Next steps for a home in Alleghany County

Mitigation cost doesn't depend on Alleghany County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find North Carolina's state radon program

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

More on how this number was built

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.