Septic suitability in Union Parish, LA
Very limited
USDA puts Union Parish, LA at "Very limited" for septic absorption fields, the dominant reading across 94.9% of the county's soil. A standard gravity system routinely fails on ground like this; the same share of the county falls in USDA's worst absorption-field bucket outright. For scale: 876.913 square miles and 20,617 people call Union Parish home.
Before you rely on this for one lot
Union Parish's rating is an average across the whole county, not a promise about any one lot inside it. The real answer for one lot is still a site-specific perc test, running about $750-$1,850 (typically near $1,300).
Budgeting for a system in Union Parish, LA
Union Parish's soil reading pushes the likely outcome toward an engineered system rather than a conventional one. Conventional systems run $3,000-$8,000 where they pass; where they don't, engineered alternatives (mound or aerobic treatment, whichever the health department requires) run $10,000-$40,000 - budget toward the higher figure until a perc test says otherwise.
Union Parish's rank among Louisiana counties
Among the 3,058 rated counties on this site, Union Parish, LA ranks 677 most-constrained nationally, and 6 of 61 within Louisiana.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems