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

Putnam County is mapped as Zone 2 - Moderate Potential by EPA — meaning the county-wide average indoor level is predicted between 2 and 4 pCi/L. Putnam County sits at the 59th percentile nationally for radon potential — above 59 of every 100 rated counties.

Where Putnam County sits nationally

Putnam County, Tennessee is home to about 84,894 people across 401.106 square miles. That works out to roughly 212 people per square mile. By population, Putnam County is the 225th largest of every county sharing its EPA zone — the 78th percentile by population within that zone. Putnam 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

Putnam County's predicted average falls between EPA's 4 pCi/L action level and the national indoor average of about 1.3 pCi/L (outdoor air runs roughly 0.4 pCi/L). A Zone 2 rating is a moderate county-wide average, not a guarantee about any one house in Putnam County — testing is the only way to know an individual home's actual level.

If Putnam County tests above the action level

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

Putnam 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.