Gregory County, South Dakota
The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). 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 Gregory County, South Dakota.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Labu-Sansarc silty clays, 9 to 35 percent slopes | 126K | Well drained | D | Very limited | Very limited |
| Okaton-Lakoma silty clays, 15 to 40 percent slopes | 53K | Well drained | D | Very limited | Very limited |
| Reliance silty clay loam, 3 to 6 percent slopes | 47K | Well drained | C | Somewhat limited | Very limited |
| Anselmo-Tassel fine sandy loams, 6 to 25 percent slopes | 26K | Well drained | A | Very limited | Very limited |
| Water | 24K | Not rated | Not rated | ||
| Labu clay, 9 to 15 percent slopes | 24K | Well drained | D | Very limited | Very limited |
| Reliance silty clay loam, 0 to 3 percent slopes | 20K | Well drained | C | Somewhat limited | Very limited |
| Millboro silty clay, 3 to 6 percent slopes | 18K | Well drained | D | Very limited | Very limited |
| Ree loam, 3 to 6 percent slopes | 17K | Well drained | C | Somewhat limited | Very limited |
| Jansen loam, 2 to 6 percent slopes | 14K | Well drained | B | Not limited | Very limited |
| Mariaville loam, 15 to 40 percent slopes | 14K | Well drained | D | Very limited | Very limited |
| Meadin sandy loam, 3 to 9 percent slopes | 12K | Excessively drained | B | Not limited | Very limited |
| Boro-Lakoma silty clays, 9 to 15 percent slopes | 12K | Well drained | C | Very limited | Very limited |
| Bon loam, channeled, 0 to 2 percent slopes, frequently flooded | 12K | Moderately well drained | C | Very limited | Very limited |
| Onita silt loam, moist | 11K | Moderately well drained | C | Somewhat limited | Very limited |
| Meadin sandy loam, 9 to 25 percent slopes | 11K | Excessively drained | B | Very limited | Very limited |
| Lakoma-Millboro silty clays, 6 to 9 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Wendte silty clay, channeled, occasionally flooded | 10K | Moderately well drained | D | Very limited | Very limited |
| Promise clay, 3 to 6 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Reliance silty clay loam, 6 to 9 percent slopes | 10K | Well drained | C | Somewhat limited | Very limited |
What This Means
Building & Foundations
About 67% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 94% 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.