Septic soil in Catahoula Parish, LA, by the numbers
Very limited
89% of Catahoula Parish, LA's surveyed soil comes back "Very limited" in USDA's own SSURGO data, the county's dominant condition for a septic absorption field. That reading means a conventional system is a poor bet here - 89% of Catahoula Parish lands in the strictest "very limited" bucket USDA uses. Catahoula Parish, LA is 709.252 square miles with a population of 8,280.
What Catahoula Parish's reading doesn't cover
Catahoula Parish's rating is an average across the whole county, not a promise about any one lot inside it. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Catahoula Parish will actually do.
What a system would cost here
With 89% of Catahoula Parish rating "Very limited", a standard gravity system is not a safe assumption here. The engineered-system range, $10,000-$40,000 (mound or aerobic treatment), is the more realistic number to plan around, against $3,000-$8,000 for a conventional system on the rare lot that passes.
Where this sits nationally
Nationally, Catahoula Parish, LA is the 1,374-most-constrained of 3,058 rated counties for septic soil. Within Louisiana alone it ranks 26 of 61.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems