Colusa County, CA Shrink-Swell Risk

Shrink-swell potential in Colusa County, CA

Moderate

Soil across 34.5% of Colusa County, CA comes back "Moderate" in USDA's shrink-swell data, averaging 5.09% 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 this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in Colusa County, CA - never a reading for one specific parcel. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Colusa County will actually do.

Colusa County: the real numbers

Colusa 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.

Colusa County's rank among California counties

Among the 3,085 rated counties on this site, Colusa County, CA ranks 278 most-constrained nationally, and 4 of 58 within California. The county spans 1,151 square miles, home to 22,074 people.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. Sharp County, AR and Cortland 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

Elsewhere in California

Every county in California is on this site, including Trinity County, CA and Tehama County, CA. The full underlying dataset is downloadable directly, one row per county.