Adams County, PA Radon Zone Data

Adams County, PA: EPA's radon zone, explained

Adams County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. That puts Adams County in the 94th percentile nationally for radon potential — higher than 94% of the counties EPA has rated.

Where Adams County sits nationally

Adams County, Pennsylvania is home to about 107,914 people across 518.576 square miles. Population density there runs about 208 people per square mile. By population, Adams County is the 183rd largest of every county sharing its EPA zone — the 83rd percentile by population within that zone. EPA's geology-based Region 3 groups Adams County with 244 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Adams County

Adams County carries a Zone 1 label because its predicted average clears 4 pCi/L outright — three-plus times the 0.4 pCi/L typical outdoors and above the 1.3 pCi/L most homes see. Being in Zone 1 raises the odds Adams County homes test above the action level, but it does not mean any specific house does — EPA recommends every home be tested, in every zone, because the only way to know is to test.

Next steps for a home in Adams County

For a Adams 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 Pennsylvania's state radon program

For Adams County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Adams 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 Adams County's figures come from

Adams County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.