What EPA's radon map says about Caroline County

Caroline County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Caroline County sits at the 19th percentile nationally for radon potential — above 19 of every 100 rated counties.

Caroline County by the numbers

About 33,477 people live in Caroline County, Virginia, spread over 527.365 square miles. That works out to roughly 63 people per square mile. Among counties sharing Caroline County's EPA zone, it outranks 56% of them by population. EPA's geology-based Region 3 groups Caroline County with 244 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

At Zone 3, Caroline County's predicted county average is under the national indoor average (~1.3 pCi/L) and well below EPA's 4 pCi/L action level — outdoor air nationally runs about 0.4 pCi/L for comparison. A Zone 3 rating means Caroline 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.

Testing and mitigation in Caroline County

Mitigation cost doesn't depend on Caroline 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

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

Caroline County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.