Phillips County, MT Shrink-Swell Risk
Phillips County, MT's soil, for shrink-swell risk
Moderate
Phillips County, MT: USDA's soil survey rates 61.6% of the county "Moderate" for shrink-swell potential (4.99% linear extensibility). Conventional foundations are the reasonable expectation here, with routine moisture-control practice rather than special engineering.
What Phillips County's reading doesn't cover
Two lots a mile apart in Phillips 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 Phillips County.
What it costs to find out, versus to ignore it
With Phillips County, MT rating "Moderate", 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.
Phillips County's rank among Montana counties
Nationally, Phillips County, MT is the 294-most-constrained of 3,085 rated counties for shrink-swell soil. Within Montana alone it ranks 4 of 54. Phillips County, MT is 5,140 square miles with a population of 4,214.
Before you act on this
Orleans Parish, LA carries this site's most-constrained reading. Cecil County, MD and Williamson County, IL 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 Flathead County, MT and Hill County, MT. The full underlying dataset is downloadable directly, one row per county.