Is Chester County, SC a radon risk area?

EPA's own radon map rates Chester County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Nationally that's the 18th percentile for radon potential — Chester County outranks 18% of every county EPA has rated.

How Chester County compares

About 32,323 people live in Chester County, South Carolina, spread over 580.865 square miles. Averaged across its land area, Chester County runs about 56 people per square mile. Rank 462 by population within its EPA zone puts Chester County at the 55th percentile among zone peers. Geologically, Chester County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

What this actually means for a house in Chester County

Chester 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. Even at Zone 3, Chester County homes are not guaranteed a low reading — zone is a county-wide average, and EPA recommends testing every home regardless of zone.

Next steps for a home in Chester County

Nothing about Chester County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find South Carolina's state radon program

Chester County's test kit answers today; a Airthings radon monitor keeps answering for Chester County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

More on how this number was built

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