St. Helena Parish, LA radon potential

EPA places St. Helena 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. That puts St. Helena Parish in the 7th percentile nationally for radon potential — higher than 7% of the counties EPA has rated.

How St. Helena Parish compares

St. Helena Parish, Louisiana is home to about 10,857 people across 408.527 square miles. Averaged across its land area, St. Helena Parish runs about 27 people per square mile. Within its own EPA zone, St. Helena Parish is bigger by population than 22% of the counties that share it. St. Helena Parish falls in EPA Radon Region 6, one of 503 counties nationally EPA assigns to that same geologic province.

Zone vs. an actual test

St. Helena Parish'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. Don't read Zone 3 as a pass for St. Helena Parish — EPA's guidance to test every home makes no exception for counties predicted low.

If St. Helena Parish tests above the action level

A short-term test kit is the standard first step and typically costs far less than mitigation itself. If a test comes back at or above 4 pCi/L, a radon mitigation system for a typical home runs roughly $800–$2,500 (around $1,200 for a common single-family install), driven mainly by foundation type, not by county.

Find Louisiana's state radon program

For St. Helena Parish, an ongoing number beats a one-time test - a Airthings radon monitor tracks St. Helena Parish'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 St. Helena Parish's figures come from

St. Helena Parish's zone, rank and region all trace back to named EPA and Census sources — the methodology guide lists exactly which ones. Whatever zone St. Helena Parish carries, the zone explainer covers what it does and doesn't tell you about any one house.