Cowlitz County, WA Shrink-Swell Risk

What Cowlitz County, WA's soil means for a foundation

Low

USDA's SSURGO data puts Cowlitz County, WA's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 2.75% across 58.3% of the county's surveyed land. Among the 3,144 counties on this site, that's the clean result: little shrink-swell movement, standard construction the likely outcome.

This is a county figure, not a lot figure

USDA's survey covers the whole of Cowlitz County, WA at once, not any single address. A local geotechnical report, typically $1,000-$5,000 (around $2,700 typical), is the only way to know what one lot in Cowlitz County will actually do.

Report cost vs. repair cost

With Cowlitz County, WA 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, Cowlitz County, WA is the 1,372-most-constrained of 3,085 rated counties for shrink-swell soil. Within Washington alone it ranks 2 of 39. The county spans 1,141 square miles, home to 113,982 people.

Before you act on this

Orleans Parish, LA carries this site's most-constrained reading. Aroostook County, ME and Jasper County, MO 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 Washington

Every county in Washington is on this site, including Thurston County, WA and Clallam County, WA. The full underlying dataset is downloadable directly, one row per county.