Benton County, IA Shrink-Swell Risk

What Benton County, IA's soil means for a foundation

Moderate

USDA's SSURGO data puts Benton County, IA's soil at "Moderate" shrink-swell potential, an area-weighted linear extensibility of 3.78% across 72.7% of the county's surveyed land. That's a middle reading: not the sharp swings that crack a foundation outright, but enough that grading and drainage are worth getting right.

This is a county figure, not a lot figure

USDA's survey covers the whole of Benton County, IA 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 Benton County, IA 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, Benton County, IA is the 684-most-constrained of 3,085 rated counties for shrink-swell soil. Within Iowa alone it ranks 54 of 99. The county spans 716 square miles, home to 25,799 people.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Sawyer County, WI and Montgomery County, TX 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 Iowa

Every county in Iowa is on this site, including Guthrie County, IA and Decatur County, IA. The full underlying dataset is downloadable directly, one row per county.