Montgomery County, IL Shrink-Swell Risk

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

Moderate

Montgomery County, IL: USDA's soil survey rates 81.6% of the county "Moderate" for shrink-swell potential (4.55% 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 Montgomery County's reading doesn't cover

Two lots a mile apart in Montgomery County can carry different soil, even though they share one countywide reading. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Montgomery County will actually do.

What it costs to find out, versus to ignore it

With Montgomery 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.

Montgomery County's rank among Illinois counties

Nationally, Montgomery County, IL is the 376-most-constrained of 3,085 rated counties for shrink-swell soil. Within Illinois alone it ranks 7 of 101. Montgomery County covers 704 square miles and counts 27,615 residents.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Clayton County, GA and Hardin County, KY 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 Morgan County, IL and Macoupin County, IL. The full underlying dataset is downloadable directly, one row per county.