St. Clair County, Alabama
The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in St. Clair County, Alabama.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Nauvoo-Townley association, 15 to 35 percent slopes | 81K | Well drained | B | Very limited | Very limited |
| Minvale-Nella-Townley association, steep | 40K | Well drained | B | Very limited | Very limited |
| Conasauga and Firestone silt loams, 1 to 8 percent slopes | 36K | Moderately well drained | D | Somewhat limited | Very limited |
| Minvale cherty loam, 8 to 15 percent slopes | 28K | Well drained | B | Somewhat limited | Somewhat limited |
| Nauvoo-Rock outcrop association, 15 to 35 percent slopes | 24K | Well drained | B | Very limited | Very limited |
| Townley silt loam, 6 to 15 percent slopes | 19K | Well drained | D | Somewhat limited | Very limited |
| Wax loam, 0 to 3 percent slopes | 14K | Moderately well drained | C/D | Very limited | Very limited |
| Townley-Nauvoo association, rolling | 14K | Well drained | D | Somewhat limited | Very limited |
| Minvale-Dewey complex, 15 to 30 percent slopes | 14K | Well drained | B | Very limited | Very limited |
| Rock outcrop-Nella-Townley association, steep | 12K | Well drained | Very limited | Very limited | |
| Water | 11K | Not rated | Not rated | ||
| Minvale cherty loam, 2 to 8 percent slopes | 10K | Well drained | B | Not limited | Somewhat limited |
| Minvale-Bodine association, steep | 10K | Well drained | B | Very limited | Very limited |
| Gaylesville silt loam, 0 to 2 percent slopes | 9K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Tanyard silt loam, 0 to 2 percent slopes | 9K | Moderately well drained | C | Very limited | Very limited |
| Nauvoo sandy loam, 6 to 15 percent slopes | 8K | Well drained | B | Somewhat limited | Somewhat limited |
| Mooreville silt loam, 0 to 2 percent slopes | 7K | Moderately well drained | C | Very limited | Very limited |
| Townley silt loam, 2 to 6 percent slopes | 7K | Well drained | D | Somewhat limited | Very limited |
| Dewey loam, 2 to 6 percent slopes | 7K | Well drained | B | Somewhat limited | Somewhat limited |
| Townley gravelly loam, 15 to 30 percent slopes | 6K | Well drained | D | Very limited | Very limited |
What This Means
Building & Foundations
About 61% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 82% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.