Warren County, TN: EPA's radon zone, explained

EPA's own radon map rates Warren County zone 2 - moderate potential, predicting a county-wide average indoor level between 2 and 4 pCi/L. Rank it against the rest of the country and Warren County lands in the 54th percentile for radon potential.

Where Warren County sits nationally

Warren County, Tennessee is home to about 43,619 people across 432.673 square miles. That works out to roughly 101 people per square mile. By population, Warren County is the 380th largest of every county sharing its EPA zone — the 63rd percentile by population within that zone. Warren County falls in EPA Radon Region 4, one of 736 counties nationally EPA assigns to that same geologic province.

Why the zone isn't the answer by itself

EPA's Zone 2 rating for Warren County sits below its own 4 pCi/L action level but above the national indoor average of about 1.3 pCi/L. Warren County's Zone 2 rating sits in the middle nationally; EPA's guidance is unchanged by that — test every home regardless of its zone.

Testing and mitigation in Warren County

For a Warren 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 Tennessee's state radon program

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

The methodology guide shows exactly which EPA and Census sources feed Warren County's numbers. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.