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

Posey County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Posey County sits at the 48th percentile nationally for radon potential — above 48 of every 100 rated counties.

Posey County by the numbers

Posey County, Indiana is home to about 25,067 people across 409.385 square miles. Averaged across its land area, Posey County runs about 61 people per square mile. By population, Posey County is the 552nd largest of every county sharing its EPA zone — the 47th percentile by population within that zone. Posey 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

Call it a middle case: above the 1.3 pCi/L most US homes average, below the 4 pCi/L line EPA uses to recommend mitigation — that's Posey County's Zone 2 prediction. Posey County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Next steps for a home in Posey County

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

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