Douglas County, IL Shrink-Swell Risk

What Douglas County, IL's soil means for a foundation

Moderate

USDA's SSURGO data puts Douglas County, IL's soil at "Moderate" shrink-swell potential, an area-weighted linear extensibility of 4.73% across 85.5% of the county's surveyed land. That's a middle reading: not the sharp swings that crack a foundation outright, but enough that grading and drainage are worth getting right.

This is a county figure, not a lot figure

USDA's survey covers the whole of Douglas County, IL at once, not any single address. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Douglas County will actually do.

Report cost vs. repair cost

With Douglas County, IL rating "Moderate", a geotechnical report is still worthwhile before a build, just less urgent than in a high-risk county. A geotechnical report runs $1,000-$5,000, typically around $2,700. Foundation repair, if a specific lot turns out to differ from the county average, runs $5,000-$15,000.

Douglas County's rank among Illinois counties

Nationally, Douglas County, IL is the 340-most-constrained of 3,085 rated counties for shrink-swell soil. Within Illinois alone it ranks 5 of 101. Douglas County, IL is 417 square miles with a population of 19,824.

Before you act on this

Orleans Parish, LA carries this site's most-constrained reading. Hardin County, IA and Kanabec County, MN are worth a look for comparison.

How this reading is built, and its real limits · Moisture management: the cheap fix that works on any soil

More of Illinois

Every county in Illinois is on this site, including Putnam County, IL and Gallatin County, IL. The full underlying dataset is downloadable directly, one row per county.