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

Orange County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Rank it against the rest of the country and Orange County lands in the 82nd percentile for radon potential.

Where Orange County sits nationally

Orange County, Indiana is home to about 19,824 people across 398.379 square miles. Averaged across its land area, Orange County runs about 50 people per square mile. By population, Orange County is the 578th largest of every county sharing its EPA zone — the 46th percentile by population within that zone. Orange County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Orange County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. Some Orange 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.

Next steps for a home 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 Indiana'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

Orange County's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.