Carter County, Montana
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 Carter County, Montana.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Eapa loam, 2 to 8 percent slopes | 92K | Well drained | B | Somewhat limited | Somewhat limited |
| Neldore-Bascovy clays, 4 to 15 percent slopes | 76K | Well drained | D | Very limited | Very limited |
| Gerdrum-Absher complex, 2 to 8 percent slopes | 61K | Well drained | D | Very limited | Not limited |
| Rock outcrop-Moyerson complex, 15 to 50 percent slopes | 50K | D | Not rated | Not rated | |
| Neldore clay, 4 to 15 percent slopes | 46K | Well drained | D | Very limited | Very limited |
| Orinoco-Yawdim silty clay loams, 4 to 15 percent slopes | 46K | Well drained | D | Somewhat limited | Very limited |
| Marvan silty clay, warm, 2 to 8 percent slopes | 46K | Well drained | D | Very limited | Not limited |
| Archin-Absher complex, 2 to 8 percent slopes | 45K | Well drained | D | Somewhat limited | Not limited |
| Marvan silty clay, warm, 0 to 2 percent slopes | 43K | Well drained | D | Very limited | Not limited |
| Archin loam, 2 to 8 percent slopes | 43K | Well drained | C | Not limited | Not limited |
| Gerdrum clay loam, 2 to 8 percent slopes | 42K | Well drained | D | Very limited | Not limited |
| Creed-Gerdrum complex, 2 to 8 percent slopes | 41K | Well drained | C | Very limited | Not limited |
| Moyerson silty clay loam, 4 to 15 percent slopes | 40K | Well drained | D | Very limited | Very limited |
| Moyerson-Orinoco silty clay loams, 4 to 15 percent slopes | 37K | Well drained | D | Very limited | Very limited |
| Absher-Gerdrum complex, 0 to 4 percent slopes | 35K | Moderately well drained | D | Very limited | Somewhat limited |
| Vanda-Marvan complex, 0 to 2 percent slopes | 30K | Well drained | D | Very limited | Very limited |
| Delpoint-Cabbart complex, 8 to 15 percent slopes | 30K | Well drained | C | Somewhat limited | Very limited |
| Havre loam, 0 to 2 percent slopes | 27K | Well drained | B | Very limited | Somewhat limited |
| Yamacall-Cabbart loams, 15 to 35 percent slopes | 26K | Well drained | B | Very limited | Very limited |
| Bickerdyke clay, 0 to 2 percent slopes | 26K | Well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 65% 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 40% of soils have significant septic limitations, while others are more suitable. A perc test is essential — conditions vary across the area.
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.