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

Rush County is mapped as Zone 1 - Highest Potential by EPA — meaning the county-wide average indoor level is predicted above 4 pCi/L. That puts Rush County in the 80th percentile nationally for radon potential — higher than 80% of the counties EPA has rated.

Rush County by the numbers

Rush County, Indiana is home to about 16,759 people across 408.137 square miles. Averaged across its land area, Rush County runs about 41 people per square mile. By population, Rush County is the 621st largest of every county sharing its EPA zone — the 42nd percentile by population within that zone. Rush County falls in EPA Radon Region 5, one of 524 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Outdoor air nationally averages about 0.4 pCi/L, indoor air about 1.3 pCi/L — Rush County's Zone 1 prediction clears both of those and EPA's fix-it threshold besides. 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 Rush County will test well under the action level, and EPA's guidance is to test regardless of zone.

Next steps for a home in Rush County

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

The methodology guide shows exactly which EPA and Census sources feed Rush County's numbers. Whatever zone Rush County carries, the zone explainer covers what it does and doesn't tell you about any one house.