Siskiyou County, CA Shrink-Swell Risk

What Siskiyou County, CA's soil means for a foundation

Low

USDA's SSURGO data puts Siskiyou County, CA's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 2.38% across 75.8% of the county's surveyed land. That's as favorable a county-level reading as this dataset produces - standard foundation practice, pending one lot's own geotechnical report.

This is a county figure, not a lot figure

USDA's survey covers the whole of Siskiyou County, CA 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 Siskiyou County, CA 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.

Where this sits nationally

Nationally, Siskiyou County, CA is the 1,661-most-constrained of 3,085 rated counties for shrink-swell soil. Within California alone it ranks 42 of 58. Siskiyou County, CA is 6,279 square miles with a population of 42,498.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Will County, IL and Onondaga County, NY 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 California

Every county in California is on this site, including Del Norte County, CA and San Diego County, CA. The full underlying dataset is downloadable directly, one row per county.