Septic soil in Ouachita Parish, LA, by the numbers

Very limited

Soil across 67.6% of Ouachita Parish, LA rates "Very limited" in USDA's septic-absorption-field interpretation. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 67.6% of the county. Ouachita Parish, LA is 610.145 square miles with a population of 157,874.

What Ouachita Parish's reading doesn't cover

This is a countywide, area-weighted figure across every soil survey map unit in Ouachita Parish, LA - never a reading for one specific parcel. A local percolation test, typically $750-$1,850 (around $1,300 typical), is the only way to know what one lot in Ouachita Parish will actually do.

What a system would cost here

With 67.6% of Ouachita 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.

Ouachita Parish's rank among Louisiana counties

Nationally, Ouachita Parish, LA is the 2,541-most-constrained of 3,058 rated counties for septic soil. Within Louisiana alone it ranks 58 of 61.

Further reading

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