Washington Parish, LA's soil, for a septic absorption field

Very limited

In Washington Parish, LA, 77.9% of the surveyed land carries a "Very limited" rating for a standard septic drain field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 77.9% of the county. Washington Parish covers 669.637 square miles and counts 45,090 residents.

This is a county figure, not a parcel figure

Nothing about Washington Parish, LA's SSURGO figure applies to a specific address - it's a county-wide average. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Washington Parish.

System cost, conventional vs. engineered

Given Washington 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.

How Washington Parish, LA compares

Nationally, Washington Parish, LA is the 2,141-most-constrained of 3,058 rated counties for septic soil. Within Louisiana alone it ranks 50 of 61.

Further reading

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