Madison County, MT Shrink-Swell Risk

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

Low

USDA's SSURGO data puts Madison County, MT's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 1.85% across 91% of the county's surveyed land. That's the easiest starting point on this site's scale - a standard foundation is the reasonable default here, though any one lot can still differ.

This is a county figure, not a lot figure

USDA's survey covers the whole of Madison County, MT 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 Madison County, MT 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 Montana counties

Nationally, Madison County, MT is the 2,126-most-constrained of 3,085 rated counties for shrink-swell soil. Within Montana alone it ranks 47 of 54. The county spans 3,588 square miles, home to 9,753 people.

For contrast

Orleans Parish, LA carries this site's most-constrained reading. Putnam County, TN and Cass 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 Montana

Every county in Montana is on this site, including Phillips County, MT and Big Horn County, MT. The full underlying dataset is downloadable directly, one row per county.