Orange County, NC: EPA's radon zone, explained

Orange County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. Orange County sits at the 28th percentile nationally for radon potential — above 28 of every 100 rated counties.

Where Orange County sits nationally

Orange County, North Carolina is home to about 152,877 people across 397.591 square miles. Population density there runs about 385 people per square mile. By population, Orange County is the 168th largest of every county sharing its EPA zone — the 84th percentile by population within that zone. Geologically, Orange County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

What this actually means for a house in Orange County

Orange County's Zone 3 prediction undercuts the roughly 1.3 pCi/L most US homes average, nowhere near EPA's 4 pCi/L threshold for recommending mitigation. Don't read Zone 3 as a pass for Orange County — EPA's guidance to test every home makes no exception for counties predicted low.

Testing and mitigation in Orange County

For a Orange 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 North Carolina's state radon program

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

Where Orange 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 Orange County carries, the zone explainer covers what it does and doesn't tell you about any one house.