Septic suitability in Gibson County, IN
Very limited
Gibson County, IN's SSURGO dominant class comes back "Very limited", covering 79.8% of the county. 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. The county spans 487.378 square miles, home to 33,038 people.
What this number does and doesn't tell you
USDA's survey covers the whole of Gibson County, IN at once, not any single address. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.
Gibson County: conventional vs. engineered cost
79.8% of Gibson County 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.
Gibson County's rank among Indiana counties
Among the 3,058 rated counties on this site, Gibson County, IN ranks 2,052 most-constrained nationally, and 82 of 90 within Indiana.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems