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

EPA's own radon map rates Northampton 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 Northampton County lands in the 98th percentile for radon potential.

Where Northampton County sits nationally

Northampton County, Pennsylvania is home to about 322,989 people across 369.787 square miles. Population density there runs about 873 people per square mile. By population, Northampton County is the 73rd largest of every county sharing its EPA zone — the 93rd percentile by population within that zone. EPA's geology-based Region 3 groups Northampton County with 244 other counties nationally sharing its underlying rock and soil profile.

Zone vs. an actual test

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Northampton County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. 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 Northampton County will test well under the action level, and EPA's guidance is to test regardless of zone.

Next steps for a home in Northampton County

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

Northampton County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone Northampton County carries, the zone explainer covers what it does and doesn't tell you about any one house.