Randolph County's SSURGO septic rating

Very limited

Randolph County, IL: USDA's soil survey calls 84.6% of the county "Very limited" for a septic leach field. 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. The county spans 575.367 square miles, home to 29,903 people.

What this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in Randolph County, IL - never a reading for one specific parcel. Budget $750-$1,850 for a real perc test on any specific parcel - that's the only figure a permit application accepts.

Randolph County: conventional vs. engineered cost

84.6% of Randolph 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 Randolph County, IL compares

Among the 3,058 rated counties on this site, Randolph County, IL ranks 1,729 most-constrained nationally, and 59 of 101 within Illinois.

Further reading

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