James City County, VA: EPA's radon zone, explained

EPA's own radon map rates James City County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Rank it against the rest of the country and James City County lands in the 25th percentile for radon potential.

How James City County compares

James City County, Virginia is home to about 82,797 people across 142.298 square miles. Population density there runs about 582 people per square mile. By population, James City County is the 246th largest of every county sharing its EPA zone — the 76th percentile by population within that zone. Geologically, James City County is grouped into EPA Region 3 alongside 244 other counties that share its rock and soil setting.

Zone vs. an actual test

A Zone 3 county like James City County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. Don't read Zone 3 as a pass for James City County — EPA's guidance to test every home makes no exception for counties predicted low.

If James City County tests above the action level

For a James City County homeowner, the order is simple: test first, since a kit costs a small fraction of what mitigation would. Only if the result clears 4 pCi/L does a system — typically $800–$2,500, about $1,200 for a common install — become worth pricing out.

Find Virginia's state radon program

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

Where James City County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.