Winnebago County's SSURGO septic rating

Very limited

Winnebago County, IL: USDA's soil survey calls 68.8% 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 68.8% of the county. For scale: 513.049 square miles and 283,790 people call Winnebago County home.

Before you rely on this for one lot

Winnebago County'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 Winnebago County, IL

Winnebago 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.

Winnebago County's rank among Illinois counties

Among the 3,058 rated counties on this site, Winnebago County, IL ranks 2,502 most-constrained nationally, and 83 of 101 within Illinois.

Related guides

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