Is Monroe County, TN a radon risk area?

EPA places Monroe County in Zone 1 - Highest Potential — a predicted county-wide average indoor radon level above 4 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Monroe County sits at the 90th percentile nationally for radon potential — above 90 of every 100 rated counties.

Where Monroe County sits nationally

About 49,154 people live in Monroe County, Tennessee, spread over 635.774 square miles. That works out to roughly 77 people per square mile. Rank 317 by population within its EPA zone puts Monroe County at the 70th percentile among zone peers. EPA's geology-based Region 4 groups Monroe County with 735 other counties nationally sharing its underlying rock and soil profile.

What this actually means for a house in Monroe County

Fixing a home becomes an EPA recommendation past 4 pCi/L, and that is precisely the side of the line Monroe County's Zone 1 prediction lands on, well above the roughly 1.3 pCi/L most US homes average. 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 Monroe County will test well under the action level, and EPA's guidance is to test regardless of zone.

If Monroe County tests above the action level

Nothing about Monroe County's EPA zone changes the mitigation number: $800–$2,500 nationally (around $1,200 typical), set by the house's foundation rather than the county it sits in — and only relevant once a test actually clears 4 pCi/L.

Find Tennessee's state radon program

Monroe County's test kit answers today; a Airthings radon monitor keeps answering for Monroe 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 Monroe County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.