Solano County, CA Shrink-Swell Risk
Solano County, CA's soil, for shrink-swell risk
Moderate
Solano County, CA: USDA's soil survey rates 46.4% of the county "Moderate" for shrink-swell potential (5.75% 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 Solano County's reading doesn't cover
Two lots a mile apart in Solano 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 Solano County, CA 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, Solano County, CA is the 165-most-constrained of 3,085 rated counties for shrink-swell soil. Within California alone it ranks 3 of 58. Solano County covers 822 square miles and counts 455,101 residents.
For contrast
Orleans Parish, LA carries this site's most-constrained reading. Lampasas County, TX and Chemung 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 Placer County, CA and Amador County, CA. The full underlying dataset is downloadable directly, one row per county.