Warren County, PA Shrink-Swell Risk
What Warren County, PA's soil means for a foundation
Low
USDA's SSURGO data puts Warren County, PA's soil at "Low" shrink-swell potential, an area-weighted linear extensibility of 1.5% across 90.3% 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 Warren 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 Warren 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, Warren County, PA is the 2,503-most-constrained of 3,085 rated counties for shrink-swell soil. Within Pennsylvania alone it ranks 34 of 67. Warren County, PA is 884 square miles with a population of 37,373.
See how another county compares
Orleans Parish, LA carries this site's most-constrained reading. Dauphin County, PA and Jersey 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 Pennsylvania
Every county in Pennsylvania is on this site, including Lehigh County, PA and Lawrence County, PA. The full underlying dataset is downloadable directly, one row per county.