Expansive clay is among the most common causes of foundation damage in America — and your county's exposure is measurable. We scored shrink-swell risk for 2,618 counties from USDA soil survey data.
Start typing your county to see its soil-risk profile and named clays.
| State | Avg high-risk soil | Counties mapped |
|---|---|---|
| Kansas | 45% | 105 |
| Missouri | 37% | 113 |
| South Dakota | 36% | 60 |
| Texas | 32% | 206 |
| Louisiana | 32% | 64 |
| Oklahoma | 26% | 77 |
| Illinois | 25% | 102 |
| Iowa | 24% | 99 |
| Arkansas | 22% | 66 |
| Montana | 22% | 43 |
| California | 22% | 41 |
| North Dakota | 21% | 53 |
| Mississippi | 19% | 82 |
| Arizona | 18% | 10 |
| Nebraska | 18% | 92 |
Foundation repair is one of the most over-sold jobs in home services — quotes for the same house can vary 3×. Before you sign anything, learn how to get honest bids and what a fair price looks like.
Before you call a foundation company →USDA's SSURGO soil survey measures linear extensibility — how much each soil shrinks and swells with moisture. We aggregate those measurements across every mapped soil component in a county, weighted by area, to score county-level foundation risk. Then each county page pairs its risk tier with method-level repair costs so you can sanity-check any bid you get.
Risk metrics are computed from USDA SSURGO soil survey data (linear extensibility of soil components, area-weighted by county). Soil varies lot to lot — this is county-scale context, not a substitute for a site-specific geotechnical or structural assessment.