Whitley County, IN: EPA's radon zone, explained
Whitley County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. Nationally that's the 86th percentile for radon potential — Whitley County outranks 86% of every county EPA has rated.
Whitley County by the numbers
Whitley County, Indiana is home to about 34,885 people across 335.622 square miles. Averaged across its land area, Whitley County runs about 104 people per square mile. By population, Whitley County is the 425th largest of every county sharing its EPA zone — the 60th percentile by population within that zone. Whitley County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.
What this actually means for a house in Whitley County
Whitley 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 Whitley 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 Whitley County
For a Whitley 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 Whitley County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Whitley 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 Whitley County's figures come from
The methodology guide shows exactly which EPA and Census sources feed Whitley County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.