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

EPA places Bucks County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Bucks County sits at the 99th percentile nationally for radon potential — above 99 of every 100 rated counties.

How Bucks County compares

Bucks County, Pennsylvania is home to about 650,131 people across 604.436 square miles. That works out to roughly 1,076 people per square mile. By population, Bucks County is the 26th largest of every county sharing its EPA zone — the 98th percentile by population within that zone. EPA's geology-based Region 3 groups Bucks County with 244 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

Bucks 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. A Zone 1 rating means testing is worth doing sooner rather than later, but it is still county-wide average, not a reading for any single house — some homes in Bucks County will test well under the action level, and EPA's guidance is to test regardless of zone.

If Bucks County tests above the action level

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

Where Bucks County's figures come from

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Bucks County carries, the zone explainer covers what it does and doesn't tell you about any one house.