Columbia County, WA Shrink-Swell Risk

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

Low

USDA's SSURGO data puts Columbia County, WA's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 1.76% across 95.6% 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 Columbia County, WA 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 Columbia 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, Columbia County, WA is the 2,212-most-constrained of 3,085 rated counties for shrink-swell soil. Within Washington alone it ranks 20 of 39. Columbia County covers 869 square miles and counts 4,025 residents.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. Winnebago County, IA and Thurston County, WA 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 Cowlitz County, WA and Whitman County, WA. The full underlying dataset is downloadable directly, one row per county.