Is Terrebonne Parish, LA a radon risk area?

EPA places Terrebonne Parish 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. Nationally, Terrebonne Parish ranks higher in radon potential than 26% of rated counties (the 26th percentile).

How Terrebonne Parish compares

About 103,864 people live in Terrebonne Parish, Louisiana, spread over 1,229.885 square miles. Averaged across its land area, Terrebonne Parish runs about 84 people per square mile. Rank 214 by population within its EPA zone puts Terrebonne Parish at the 79th percentile among zone peers. Terrebonne Parish falls in EPA Radon Region 6, one of 503 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

A Zone 3 county like Terrebonne Parish 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 Terrebonne Parish'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 Terrebonne Parish

Nothing about Terrebonne Parish'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 Louisiana's state radon program

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

More on how this number was built

The methodology guide shows exactly which EPA and Census sources feed Terrebonne Parish's numbers. If you're unsure why a low zone still deserves a test, the zone explainer covers that directly.