Williamsburg County, SC Shrink-Swell Risk
Williamsburg County, SC's soil, for shrink-swell risk
Low
Williamsburg County, SC: USDA's soil survey rates 86.1% of the county "Low" for shrink-swell potential (1.74% linear extensibility). That's the easiest starting point on this site's scale - a standard foundation is the reasonable default here, though any one lot can still differ.
What Williamsburg County's reading doesn't cover
Two lots a mile apart in Williamsburg 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 Williamsburg County.
What it costs to find out, versus to ignore it
With Williamsburg County, SC rating "Low", 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.
How Williamsburg County, SC compares
Nationally, Williamsburg County, SC is the 2,232-most-constrained of 3,085 rated counties for shrink-swell soil. Within South Carolina alone it ranks 24 of 46. Williamsburg County, SC is 934 square miles with a population of 29,865.
See how another county compares
Orleans Parish, LA carries this site's most-constrained reading. Bernalillo County, NM and Stephenson County, IL 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 Carolina
Every county in South Carolina is on this site, including Oconee County, SC and Greenwood County, SC. The full underlying dataset is downloadable directly, one row per county.