Monroe County, AL: EPA's radon zone, explained

EPA places Monroe 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. Rank it against the rest of the country and Monroe County lands in the 12th percentile for radon potential.

Where Monroe County sits nationally

Monroe County, Alabama is home to about 19,057 people across 1,025.669 square miles. Population density there runs about 19 people per square mile. By population, Monroe County is the 642nd largest of every county sharing its EPA zone — the 38th percentile by population within that zone. 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

Monroe County's Zone 3 prediction undercuts the roughly 1.3 pCi/L most US homes average, nowhere near EPA's 4 pCi/L threshold for recommending mitigation. Low doesn't mean zero: EPA's own data shows homes in Zone 3 counties like Monroe County testing above the action level often enough that skipping a test isn't the safe assumption.

If Monroe County tests above the action level

For a Monroe 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 Alabama's state radon program

For Monroe County, an ongoing number beats a one-time test - a Airthings radon monitor tracks Monroe County's levels over time. RadonZoneCheck earns a commission there, at no extra cost to you. Use code RADONZONE-10OFF at checkout for 10% off.

Where Monroe County's figures come from

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