Grundy County, IL's soil, for a septic absorption field

Very limited

In Grundy County, IL, 96.4% of the surveyed land carries a "Very limited" rating for a standard septic drain field. That reading means a conventional system is a poor bet here - 96.4% of Grundy County lands in the strictest "very limited" bucket USDA uses. Grundy County covers 418.133 square miles and counts 53,835 residents.

This is a county figure, not a parcel figure

Nothing about Grundy County, IL's SSURGO figure applies to a specific address - it's a county-wide average. A site-specific perc test, usually $750-$1,850, is what a health department will actually require before permitting a lot in Grundy County.

System cost, conventional vs. engineered

Given Grundy 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.

How Grundy County, IL compares

Nationally, Grundy County, IL is the 465-most-constrained of 3,058 rated counties for septic soil. Within Illinois alone it ranks 21 of 101.

Before you act on this

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