Allegheny County, PA Shrink-Swell Risk

What Allegheny County, PA's soil means for a foundation

Low

USDA's SSURGO data puts Allegheny County, PA's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 2.53% across 67.1% of the county's surveyed land. Among the 3,144 counties on this site, that's the clean result: little shrink-swell movement, standard construction the likely outcome.

This is a county figure, not a lot figure

USDA's survey covers the whole of Allegheny County, PA 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 Allegheny County, PA 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.

Where this sits nationally

Nationally, Allegheny County, PA is the 1,534-most-constrained of 3,085 rated counties for shrink-swell soil. Within Pennsylvania alone it ranks 3 of 67. The county spans 730 square miles, home to 1,231,814 people.

See how another county compares

Orleans Parish, LA carries this site's most-constrained reading. Greenwood County, SC and Orange County, FL 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 Pennsylvania

Every county in Pennsylvania is on this site, including Delaware County, PA and Blair County, PA. The full underlying dataset is downloadable directly, one row per county.