23 counties mapped. On average, 1% of Maryland county soil area is high shrink-swell clay (USDA SSURGO).
Higher percentages mean more of a county's mapped soil is shrink-swell clay that expands and contracts with moisture. This is county-scale exposure, not a diagnosis of any single home — but it tells you whether soil movement belongs on your radar.
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Before you call a foundation company →| County | Tier | High-risk % | Moderate % |
|---|---|---|---|
| Washington | Moderate | 11% | 33% |
| Harford | Moderate | 6% | 9% |
| Allegany | Low | 5% | 6% |
| Frederick | Low | 4% | 18% |
| Cecil | Low | 1% | 3% |
| Baltimore | Low | 1% | 11% |
| Howard | Low | 1% | 17% |
| Montgomery | Low | 1% | 15% |
| Prince George's | Low | 0% | 5% |
| Anne Arundel | Low | 0% | 13% |
| Calvert | Low | 0% | 2% |
| Caroline | Low | 0% | 1% |
| Carroll | Low | 0% | 6% |
| Charles | Low | 0% | 6% |
| Dorchester | Low | 0% | 11% |
| Garrett | Low | 0% | 8% |
| Kent | Low | 0% | 2% |
| Queen Anne's | Low | 0% | 0% |
| St. Mary's | Low | 0% | 5% |
| Somerset | Low | 0% | 1% |
| Talbot | Low | 0% | 1% |
| Wicomico | Low | 0% | 6% |
| Worcester | Low | 0% | 1% |
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.