West Carroll Parish's SSURGO septic rating
Very limited
West Carroll Parish, LA's SSURGO dominant class comes back "Very limited", covering 97.8% of the county. Practically, that rules out a simple gravity system for most of the county - 97.8% of it sits in USDA's most-constrained bucket. The county spans 359.686 square miles, home to 9,254 people.
What this number does and doesn't tell you
West Carroll Parish's rating is an average across the whole county, not a promise about any one lot inside it. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
West Carroll Parish: conventional vs. engineered cost
97.8% of West Carroll Parish carrying a "Very limited" reading changes the realistic budget here. 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.
Where this sits nationally
Among the 3,058 rated counties on this site, West Carroll Parish, LA ranks 281 most-constrained nationally, and 4 of 61 within Louisiana.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems