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

EPA's own radon map rates Putnam County zone 3 - low potential, predicting a county-wide average indoor level below 2 pCi/L. Nationally, Putnam County ranks higher in radon potential than 25% of rated counties (the 25th percentile).

Where Putnam County sits nationally

Putnam County, Florida is home to about 77,301 people across 728.396 square miles. That works out to roughly 106 people per square mile. By population, Putnam County is the 257th largest of every county sharing its EPA zone — the 75th percentile by population within that zone. EPA's geology-based Region 4 groups Putnam County with 735 other counties nationally sharing its underlying rock and soil profile.

Why the zone isn't the answer by itself

A Zone 3 county like Putnam County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. A Zone 3 label describes Putnam County's average, not any one basement or slab in it — testing is still the only way an individual homeowner actually finds out.

Next steps for a home in Putnam County

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 Florida'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

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