Modoc County, CA Shrink-Swell Risk

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

Moderate

USDA's SSURGO data puts Modoc County, CA's soil at "Moderate" shrink-swell potential, an area-weighted linear extensibility of 3.55% across 45.7% of the county's surveyed land. Conventional foundations are the reasonable expectation here, with routine moisture-control practice rather than special engineering.

This is a county figure, not a lot figure

USDA's survey covers the whole of Modoc 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 Modoc 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.

Modoc County's rank among California counties

Nationally, Modoc County, CA is the 810-most-constrained of 3,085 rated counties for shrink-swell soil. Within California alone it ranks 14 of 58. Modoc County covers 3,948 square miles and counts 8,491 residents.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Sedgwick County, CO and Hamilton County, IA 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 Plumas County, CA and San Bernardino County, CA. The full underlying dataset is downloadable directly, one row per county.