Madison County, IL Shrink-Swell Risk

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

Moderate

USDA's SSURGO data puts Madison County, IL's soil at "Moderate" shrink-swell potential, an area-weighted linear extensibility of 4.22% across 68.2% of the county's surveyed land. Conventional foundations are the reasonable expectation here, with routine moisture-control practice rather than special engineering.

This is a county figure, not a lot figure

USDA's survey covers the whole of Madison County, IL at once, not any single address. The real answer for one lot is still a site-specific geotechnical report, running about $1,000-$5,000 (typically near $2,700).

Report cost vs. repair cost

With Madison 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.

Madison County's rank among Illinois counties

Nationally, Madison County, IL is the 460-most-constrained of 3,085 rated counties for shrink-swell soil. Within Illinois alone it ranks 17 of 101. Madison County covers 716 square miles and counts 263,017 residents.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Bucks County, PA and Rice County, KS 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 Peoria County, IL and Tazewell County, IL. The full underlying dataset is downloadable directly, one row per county.