Wayne County, IN: the USDA septic-suitability picture
Very limited
Wayne County, IN: USDA's soil survey calls 97.2% of the county "Very limited" for a septic leach field. Expect the ground itself to work against a plain gravity system; USDA's strictest bucket alone covers 97.2% of the county. For scale: 401.755 square miles and 66,410 people call Wayne County home.
Before you rely on this for one lot
USDA's survey covers the whole of Wayne County, IN at once, not any single address. 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 Wayne County, IN
Wayne County'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.
Where this sits nationally
Among the 3,058 rated counties on this site, Wayne County, IN ranks 349 most-constrained nationally, and 26 of 90 within Indiana.
Before you act on this
How this rating is built, and its real limits · Conventional vs. engineered septic systems