Is Monroe County, FL a radon risk area?

Monroe County is mapped as Zone 3 - Low Potential by EPA — meaning the county-wide average indoor level is predicted below 2 pCi/L. That puts Monroe County in the 25th percentile nationally for radon potential — higher than 25% of the counties EPA has rated.

Where Monroe County sits nationally

About 80,908 people live in Monroe County, Florida, spread over 983.043 square miles. Population density there runs about 82 people per square mile. Rank 250 by population within its EPA zone puts Monroe County at the 76th 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.

Why the zone isn't the answer by itself

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Monroe County's Zone 3 prediction is the low end of the scale. A Zone 3 label describes Monroe 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 Monroe County

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 Florida'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. Code RADONZONE-10OFF takes 10% off at checkout.

More on how this number was built

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. The guide to what a radon zone actually means covers why testing matters in every zone, not just Zone 1.