Clay County, IL Shrink-Swell Risk

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

Moderate

USDA's SSURGO data puts Clay County, IL's soil at "Moderate" shrink-swell potential, an area-weighted linear extensibility of 3.54% across 70% 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 Clay 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 Clay County will actually do.

Report cost vs. repair cost

With Clay 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.

Where this sits nationally

Nationally, Clay County, IL is the 817-most-constrained of 3,085 rated counties for shrink-swell soil. Within Illinois alone it ranks 57 of 101. Clay County, IL is 468 square miles with a population of 12,821.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. San Juan County, WA and Mercer County, OH 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 McHenry County, IL and Champaign County, IL. The full underlying dataset is downloadable directly, one row per county.