Is Collier County, FL a radon risk area?

EPA places Collier County in Zone 3 - Low Potential — a predicted county-wide average indoor radon level below 2 pCi/L, based on the geology, soil and aerial radioactivity data behind EPA's national map. Collier County sits at the 31st percentile nationally for radon potential — above 31 of every 100 rated counties.

Collier County by the numbers

About 416,233 people live in Collier County, Florida, spread over 1,997.014 square miles. Population density there runs about 208 people per square mile. Rank 65 by population within its EPA zone puts Collier County at the 94th percentile among zone peers. Geologically, Collier County is grouped into EPA Region 4 alongside 735 other counties that share its rock and soil setting.

What this actually means for a house in Collier County

A Zone 3 county like Collier County is predicted closer to the 0.4 pCi/L typical outdoors than to EPA's 4 pCi/L action level. A Zone 3 rating means Collier County's county-wide average is predicted low, but EPA is explicit that a meaningful share of homes in low-potential zones still test above the action level — a low zone is not a reason to skip testing.

If Collier County tests above the action level

Nothing about Collier 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 Florida's state radon program

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

More on how this number was built

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