Gallatin County's SSURGO septic rating

Very limited

Gallatin County, IL: USDA's soil survey calls 86.9% of the county "Very limited" for a septic leach field. Practically, that rules out a simple gravity system for most of the county - 86.9% of it sits in USDA's most-constrained bucket. For scale: 322.942 square miles and 4,690 people call Gallatin County home.

Before you rely on this for one lot

Two lots a mile apart in Gallatin County can carry different soil, even though they share one countywide rating. 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 Gallatin County, IL

Gallatin 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, Gallatin County, IL ranks 1,554 most-constrained nationally, and 54 of 101 within Illinois.

Related guides

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