Is Greenwood County, SC a radon risk area?

Greenwood County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Greenwood County sits at the 24th percentile nationally for radon potential — above 24 of every 100 rated counties.

Where Greenwood County sits nationally

About 70,041 people live in Greenwood County, South Carolina, spread over 455.606 square miles. Population density there runs about 154 people per square mile. Rank 271 by population within its EPA zone puts Greenwood County at the 74th percentile among zone peers. EPA's geology-based Region 4 groups Greenwood County with 735 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Greenwood County's Zone 3 prediction undercuts the roughly 1.3 pCi/L most US homes average, nowhere near EPA's 4 pCi/L threshold for recommending mitigation. Don't read Zone 3 as a pass for Greenwood County — EPA's guidance to test every home makes no exception for counties predicted low.

If Greenwood County tests above the action level

Nothing about Greenwood 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

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

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.