Is Marengo County, AL a radon risk area?

EPA places Marengo 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. That puts Marengo County in the 12th percentile nationally for radon potential — higher than 12% of the counties EPA has rated.

Marengo County by the numbers

About 18,512 people live in Marengo County, Alabama, spread over 976.898 square miles. Population density there runs about 19 people per square mile. Rank 654 by population within its EPA zone puts Marengo County at the 37th percentile among zone peers. Marengo 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

Well clear of both the 1.3 pCi/L national indoor average and EPA's 4 pCi/L action level, Marengo County's Zone 3 prediction is the low end of the scale. A Zone 3 rating means Marengo 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 Marengo County tests above the action level

Nothing about Marengo 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 Alabama's state radon program

Marengo County's test kit answers today; a Airthings radon monitor keeps answering for Marengo 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

Every figure on this page traces to EPA's own Map of Radon Zones and Census data, documented in the methodology guide. Whatever zone Marengo County carries, the zone explainer covers what it does and doesn't tell you about any one house.