What EPA's radon map says about Mathews County

Mathews County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. That puts Mathews County in the 6th percentile nationally for radon potential — higher than 6% of the counties EPA has rated.

Where Mathews County sits nationally

About 8,602 people live in Mathews County, Virginia, spread over 85.912 square miles. Averaged across its land area, Mathews County runs about 100 people per square mile. Among counties sharing Mathews County's EPA zone, it outranks 17% of them by population. EPA's geology-based Region 3 groups Mathews County with 244 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Mathews County's predicted average sits below the national indoor average of about 1.3 pCi/L, well under EPA's 4 pCi/L action level. A Zone 3 rating means Mathews 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 Mathews County tests above the action level

Mitigation cost doesn't depend on Mathews 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

Mathews County's test kit answers today; a Airthings radon monitor keeps answering for Mathews 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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Mathews County carries, the zone explainer covers what it does and doesn't tell you about any one house.