Island County, WA Shrink-Swell Risk

Shrink-swell potential in Island County, WA

Low

Soil across 90.8% of Island County, WA comes back "Low" in USDA's shrink-swell data, averaging 1.44% linear extensibility. That's as favorable a county-level reading as this dataset produces - standard foundation practice, pending one lot's own geotechnical report.

What this number does and doesn't tell you

This is a countywide, area-weighted figure across every soil survey map unit in Island County, WA - never a reading for one specific parcel. 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 Island County.

Island County: the real numbers

Island 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.

Island County's rank among Washington counties

Among the 3,085 rated counties on this site, Island County, WA ranks 2,573 most-constrained nationally, and 33 of 39 within Washington. The county spans 209 square miles, home to 86,478 people.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. Carroll County, IA and Adams 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

Elsewhere in Washington

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