What St. James Parish, LA's soil rates for a septic system

Very limited

90.2% of St. James 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. Practically, that rules out a simple gravity system for most of the county - 90.2% of it sits in USDA's most-constrained bucket. St. James Parish covers 237.861 square miles and counts 19,110 residents.

This is a county figure, not a parcel figure

This is a countywide, area-weighted figure across every soil survey map unit in St. James Parish, LA - never a reading for one specific parcel. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in St. James Parish.

System cost, conventional vs. engineered

Given St. James Parish's rating, plan for the engineered-system range rather than the conventional one. 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, St. James Parish, LA is the 1,248-most-constrained of 3,058 rated counties for septic soil. Within Louisiana alone it ranks 19 of 61.

Related guides

How this rating is built, and its real limits · Conventional vs. engineered septic systems