Cook County, IL Shrink-Swell Risk

Shrink-swell potential in Cook County, IL

Moderate

Soil across 41.7% of Cook County, IL comes back "Moderate" in USDA's shrink-swell data, averaging 4.41% linear extensibility. A real but modest amount of movement - standard foundations usually hold up, but drainage and moisture control around the foundation still matter more than on low-risk soil.

What this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in Cook County, IL - never a reading for one specific parcel. The real answer for one lot is still a site-specific geotechnical report, running about $1,000-$5,000 (typically near $2,700).

Cook County: the real numbers

Cook County's soil reading points toward standard foundation practice as the likely outcome, not the exception. 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

Among the 3,085 rated counties on this site, Cook County, IL ranks 406 most-constrained nationally, and 8 of 101 within Illinois. The county spans 945 square miles, home to 5,182,617 people.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Weakley County, TN and Fairfield 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

Elsewhere in Illinois

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