Williamson County, IL Shrink-Swell Risk

Williamson County, IL's soil, for shrink-swell risk

Low

Williamson County, IL: USDA's soil survey rates 67.2% of the county "Low" for shrink-swell potential (2.61% linear extensibility). Among the 3,144 counties on this site, that's the clean result: little shrink-swell movement, standard construction the likely outcome.

What Williamson County's reading doesn't cover

Two lots a mile apart in Williamson County can carry different soil, even though they share one countywide reading. A site-specific soil report, usually $1,000-$5,000, is what an engineer would actually pull before designing a foundation on a lot in Williamson County.

What it costs to find out, versus to ignore it

With Williamson County, IL rating "Low", 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, Williamson County, IL is the 1,469-most-constrained of 3,085 rated counties for shrink-swell soil. Within Illinois alone it ranks 97 of 101. Williamson County covers 420 square miles and counts 67,064 residents.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. Little River County, AR and Marion County, TN 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 Lake County, IL and Edwards County, IL. The full underlying dataset is downloadable directly, one row per county.