What EPA's radon map says about Chesterfield County

EPA's own radon map rates Chesterfield 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 Chesterfield County lands in the 21st percentile for radon potential.

Chesterfield County by the numbers

About 44,488 people live in Chesterfield County, South Carolina, spread over 798.986 square miles. That works out to roughly 56 people per square mile. Among counties sharing Chesterfield County's EPA zone, it outranks 64% of them by population. Chesterfield County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

At Zone 3, Chesterfield 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. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Chesterfield County testing above the action level often enough that skipping a test isn't the safe assumption.

Next steps for a home in Chesterfield County

Mitigation cost doesn't depend on Chesterfield 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 South Carolina's state radon program

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

The methodology guide shows exactly which EPA and Census sources feed Chesterfield County's numbers. Whatever zone Chesterfield County carries, the zone explainer covers what it does and doesn't tell you about any one house.