De Witt County's SSURGO septic rating
Very limited
De Witt County, IL: USDA's soil survey calls 92.4% of the county "Very limited" for a septic leach field. This is the reading that pushes a project toward an engineered system rather than a conventional one, and it covers 92.4% of De Witt County's land. The county spans 397.561 square miles, home to 15,319 people.
What this number does and doesn't tell you
USDA's survey covers the whole of De Witt County, IL 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.
De Witt County: conventional vs. engineered cost
92.4% of De Witt 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.
How De Witt County, IL compares
Among the 3,058 rated counties on this site, De Witt County, IL ranks 990 most-constrained nationally, and 42 of 101 within Illinois.
Related guides
How this rating is built, and its real limits · Conventional vs. engineered septic systems