Septic soil in Ford County, IL, by the numbers

Very limited

Soil across 99.8% of Ford County, IL rates "Very limited" in USDA's septic-absorption-field interpretation. 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. Ford County covers 485.597 square miles and counts 13,451 residents.

This is a county figure, not a parcel figure

This is a countywide, area-weighted figure across every soil survey map unit in Ford County, IL - never a reading for one specific parcel. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Ford County.

System cost, conventional vs. engineered

Given Ford County's rating, plan for the engineered-system range rather than the conventional one. The engineered-system range, $10,000-$40,000 (mound or aerobic treatment), is the more realistic number to plan around, against $3,000-$8,000 for a conventional system on the rare lot that passes.

Ford County's rank among Illinois counties

Nationally, Ford County, IL is the 6-most-constrained of 3,058 rated counties for septic soil. Within Illinois alone it ranks 1 of 101.

Related guides

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