York County, SC: EPA's radon zone, explained

EPA places York County in Zone 2 - Moderate Potential — a predicted county-wide average indoor radon level between 2 and 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. York County sits at the 64th percentile nationally for radon potential — above 64 of every 100 rated counties.

Where York County sits nationally

York County, South Carolina is home to about 303,001 people across 680.607 square miles. Population density there runs about 445 people per square mile. By population, York County is the 76th largest of every county sharing its EPA zone — the 93rd percentile by population within that zone. Geologically, York County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

Zone vs. an actual test

York County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A county-wide moderate average, like York County's, can still hide a specific house well above or below it — testing is what actually answers the question.

Next steps for a home in York County

For a York 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 South Carolina's state radon program

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

Where York County's figures come from

York 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.