San Luis Obispo County, CA Shrink-Swell Risk
San Luis Obispo County's SSURGO shrink-swell reading
Moderate
In San Luis Obispo County, CA, 47% of the surveyed soil carries a "Moderate" shrink-swell rating, 3.63% linear extensibility on average. 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.
Before you rely on this for one address
San Luis Obispo County's reading is an average across the whole county, not a promise about any one lot inside it. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in San Luis Obispo County will actually do.
Budgeting for San Luis Obispo County, CA
San Luis Obispo County's soil reading points toward standard foundation practice as the likely outcome, not the exception. 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
Among the 3,085 rated counties on this site, San Luis Obispo County, CA ranks 769 most-constrained nationally, and 13 of 58 within California. San Luis Obispo County, CA is 3,301 square miles with a population of 281,843.
Before you act on this
Orleans Parish, LA carries this site's most-constrained reading. Harding County, NM and Haines Borough, AK 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
Elsewhere in California
Every county in California is on this site, including Santa Barbara County, CA and Trinity County, CA. The full underlying dataset is downloadable directly, one row per county.