Monroe County, IN radon potential

EPA's own radon map rates Monroe County zone 1 - highest potential, predicting a county-wide average indoor level above 4 pCi/L. That puts Monroe County in the 95th percentile nationally for radon potential — higher than 95% of the counties EPA has rated.

How Monroe County compares

Monroe County, Indiana is home to about 140,702 people across 394.523 square miles. Population density there runs about 357 people per square mile. Within its own EPA zone, Monroe County is bigger by population than 87% of the counties that share it. Monroe 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

Where the national indoor average runs about 1.3 pCi/L, Monroe County's Zone 1 rating puts its predicted county average above EPA's 4 pCi/L action level itself. Being in Zone 1 raises the odds Monroe 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.

If Monroe County tests above the action level

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Indiana's state radon program

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

Where Monroe County's figures come from

Monroe 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.