Union County, SD Shrink-Swell Risk

Union County, SD's soil, for shrink-swell risk

Moderate

Union County, SD: USDA's soil survey rates 51% of the county "Moderate" for shrink-swell potential (5.99% 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 Union County's reading doesn't cover

Two lots a mile apart in Union 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 Union County.

What it costs to find out, versus to ignore it

With Union County, SD 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, Union County, SD is the 132-most-constrained of 3,085 rated counties for shrink-swell soil. Within South Dakota alone it ranks 11 of 66. Union County, SD is 461 square miles with a population of 17,402.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Reeves County, TX and Grafton County, NH 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 South Dakota

Every county in South Dakota is on this site, including McCook County, SD and Potter County, SD. The full underlying dataset is downloadable directly, one row per county.