Plymouth County, IA Shrink-Swell Risk

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

Moderate

USDA's SSURGO data puts Plymouth County, IA's soil at "Moderate" shrink-swell potential, an area-weighted linear extensibility of 3.56% across 72% 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 Plymouth 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 Plymouth 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, Plymouth County, IA is the 802-most-constrained of 3,085 rated counties for shrink-swell soil. Within Iowa alone it ranks 60 of 99. Plymouth County, IA is 863 square miles with a population of 25,825.

Before you act on this

Orleans Parish, LA carries this site's most-constrained reading. Chicot County, AR and Buchanan County, IA 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 Pottawattamie County, IA and Buena Vista County, IA. The full underlying dataset is downloadable directly, one row per county.