Madison County, ID Shrink-Swell Risk

What Madison County, ID's soil means for a foundation

Low

USDA's SSURGO data puts Madison County, ID's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 1.79% across 90% 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 Madison County, ID 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 Madison County will actually do.

Report cost vs. repair cost

With Madison County, ID 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.

Madison County's rank among Idaho counties

Nationally, Madison County, ID is the 2,177-most-constrained of 3,085 rated counties for shrink-swell soil. Within Idaho alone it ranks 33 of 44. The county spans 469 square miles, home to 55,549 people.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Denton County, TX and Steele County, ND 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 Idaho

Every county in Idaho is on this site, including Gooding County, ID and Washington County, ID. The full underlying dataset is downloadable directly, one row per county.