What EPA's radon map says about Cumberland County

EPA places Cumberland 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. That puts Cumberland County in the 76th percentile nationally for radon potential — higher than 76% of the counties EPA has rated.

How Cumberland County compares

About 10,062 people live in Cumberland County, Virginia, spread over 297.474 square miles. Population density there runs about 34 people per square mile. Among counties sharing Cumberland County's EPA zone, it outranks 29% of them by population. EPA's geology-based Region 3 groups Cumberland County with 244 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Cumberland County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. 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 Cumberland County specifically.

Testing and mitigation in Cumberland County

Mitigation cost doesn't depend on Cumberland 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 Virginia'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. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

Cumberland County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Cumberland County carries, the zone explainer covers what it does and doesn't tell you about any one house.