Hamlin County, SD Shrink-Swell Risk
Hamlin County, SD's soil, for shrink-swell risk
Moderate
Hamlin County, SD: USDA's soil survey rates 81.8% of the county "Moderate" for shrink-swell potential (3.66% linear extensibility). Conventional foundations are the reasonable expectation here, with routine moisture-control practice rather than special engineering.
What Hamlin County's reading doesn't cover
Two lots a mile apart in Hamlin County can carry different soil, even though they share one countywide reading. The real answer for one lot is still a site-specific geotechnical report, running about $1,000-$5,000 (typically near $2,700).
What it costs to find out, versus to ignore it
With Hamlin 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, Hamlin County, SD is the 752-most-constrained of 3,085 rated counties for shrink-swell soil. Within South Dakota alone it ranks 49 of 66. Hamlin County covers 507 square miles and counts 6,596 residents.
See how another county compares
Orleans Parish, LA carries this site's most-constrained reading. Wilbarger County, TX and Madison County, MO 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 Custer County, SD and Hanson County, SD. The full underlying dataset is downloadable directly, one row per county.