Fallon 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 Fallon County, Montana.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Cabbart-Rock outcrop-Delpoint complex, 15 to 50 percent slopes | 72K | Well drained | D | Very limited | Very limited |
| Cabbart-Cambeth silt loams, 8 to 15 percent slopes | 57K | Well drained | D | Very limited | Very limited |
| Neldore clay, 4 to 15 percent slopes | 36K | Well drained | D | Very limited | Very limited |
| Eapa loam, 2 to 8 percent slopes | 35K | Well drained | B | Somewhat limited | Somewhat limited |
| Archin loam, 2 to 8 percent slopes | 26K | Well drained | C | Not limited | Not limited |
| Kremlin loam, warm, 2 to 8 percent slopes | 23K | Well drained | B | Not limited | Somewhat limited |
| Neldore-Bascovy clays, 4 to 15 percent slopes | 22K | Well drained | D | Very limited | Very limited |
| Cambeth-Cabbart silt loams, 2 to 8 percent slopes | 22K | Well drained | C | Somewhat limited | Very limited |
| Delpoint-Cabbart complex, 8 to 15 percent slopes | 22K | Well drained | C | Somewhat limited | Very limited |
| Havre loam, 0 to 2 percent slopes | 20K | Well drained | B | Very limited | Somewhat limited |
| Gerdrum clay loam, 2 to 8 percent slopes | 20K | Well drained | D | Very limited | Not limited |
| Lonna silt loam, 2 to 8 percent slopes | 19K | Well drained | C | Not limited | Very limited |
| Chinook sandy loam, 2 to 8 percent slopes | 19K | Well drained | A | Not limited | Not limited |
| Gerdrum-Absher complex, 2 to 8 percent slopes | 18K | Well drained | D | Very limited | Not limited |
| Blacksheep-Twilight fine sandy loams, complex, 8 to 15 percent slopes | 17K | Well drained | D | Somewhat limited | Very limited |
| Archin-Absher complex, 2 to 8 percent slopes | 16K | Well drained | D | Somewhat limited | Not limited |
| Lonna-Cabbart silt loams, 8 to 25 percent slopes | 16K | Well drained | B | Somewhat limited | Somewhat limited |
| Busby-Twilight-Blacksheep fine sandy loams, 8 to 35 percent slopes | 14K | Well drained | A | Very limited | Very limited |
| Cabbart silt loam, 4 to 15 percent slopes | 14K | Well drained | D | Very limited | Very limited |
| Bonfri-Cabbart loams, 8 to 15 percent slopes | 13K | Well drained | C | Somewhat limited | Very limited |
What This Means
Building & Foundations
About 54% 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 61% 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.