What EPA's radon map says about McMinn County

McMinn 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 McMinn County lands in the 91st percentile for radon potential.

How McMinn County compares

About 56,754 people live in McMinn County, Tennessee, spread over 430.117 square miles. Averaged across its land area, McMinn County runs about 132 people per square mile. Among counties sharing McMinn County's EPA zone, it outranks 73% of them by population. McMinn County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

Where the national indoor average runs about 1.3 pCi/L, McMinn 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 McMinn 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 McMinn County tests above the action level

Mitigation cost doesn't depend on McMinn County's zone — it depends on the house's foundation. A typical system runs $800–$2,500 (about $1,200 typical), and testing first is what tells you whether that's needed at all.

Find Tennessee's state radon program

McMinn County's test kit answers today; a Airthings radon monitor keeps answering for McMinn County over time. Affiliate link, RadonZoneCheck earns a commission there, at no extra cost to you. RADONZONE-10OFF at checkout knocks 10% off.

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed McMinn County's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.