What EPA's radon map says about York County

EPA's own radon map rates York County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. Rank it against the rest of the country and York County lands in the 99th percentile for radon potential.

How York County compares

About 471,240 people live in York County, Pennsylvania, spread over 904.352 square miles. Population density there runs about 521 people per square mile. Among counties sharing York County's EPA zone, it outranks 96% of them by population. Geologically, York County is grouped into EPA Region 3 alongside 244 other counties that share its rock and soil setting.

Why the zone isn't the answer by itself

York County's predicted average sits above EPA's own action level of 4 pCi/L — the concentration at which EPA recommends fixing a home — versus a national average around 1.3 pCi/L indoors and 0.4 pCi/L outdoors. Some York County homes will test comfortably under the action level despite the county's Zone 1 rating — the only way to know which kind of home you have is an actual test.

If York County tests above the action level

Mitigation cost doesn't depend on York 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 Pennsylvania's state radon program

York County's test kit answers today; a Airthings radon monitor keeps answering for York 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 York County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.