Multnomah County, OR Shrink-Swell Risk

Multnomah County, OR's soil, for shrink-swell risk

Low

Multnomah County, OR: USDA's soil survey rates 91.4% of the county "Low" for shrink-swell potential (1.68% linear extensibility). Among the 3,144 counties on this site, that's the clean result: little shrink-swell movement, standard construction the likely outcome.

What Multnomah County's reading doesn't cover

Two lots a mile apart in Multnomah County can carry different soil, even though they share one countywide reading. A site-specific soil report, usually $1,000-$5,000, is what an engineer would actually pull before designing a foundation on a lot in Multnomah County.

What it costs to find out, versus to ignore it

With Multnomah County, OR 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.

How Multnomah County, OR compares

Nationally, Multnomah County, OR is the 2,299-most-constrained of 3,085 rated counties for shrink-swell soil. Within Oregon alone it ranks 34 of 36. The county spans 431 square miles, home to 795,897 people.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. Houston County, MN and Clay County, NE 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 Oregon

Every county in Oregon is on this site, including Jackson County, OR and Clatsop County, OR. The full underlying dataset is downloadable directly, one row per county.