Granite County Area, Montana
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate 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 Granite County Area, Montana.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Roy-Shawmut-Danvers complex, 15 to 35 percent slopes | 10K | Well drained | C | Very limited | Very limited |
| Whitecow gravelly loam, cool, 35 to 60 percent slopes | 10K | Well drained | B | Very limited | Very limited |
| Whitecow gravelly loam, 35 to 60 percent slopes | 9K | Well drained | B | Very limited | Very limited |
| Elve gravelly loam, 15 to 35 percent slopes | 7K | Somewhat excessively drained | B | Very limited | Very limited |
| Trapps gravelly loam, 15 to 35 percent slopes | 7K | Well drained | C | Very limited | Very limited |
| Worock gravelly loam, cool, 15 to 35 percent slopes | 6K | Well drained | C | Very limited | Very limited |
| Braziel gravelly loam, 15 to 35 percent slopes | 6K | Well drained | C | Very limited | Very limited |
| Roy-Fergus complex, 15 to 35 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Windham-Lap-Rock outcrop complex, 35 to 60 percent slopes | 5K | Well drained | B | Very limited | Very limited |
| Yreka gravelly loam, cool, 15 to 35 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Bignell, dry-Yreka, cool complex, 15 to 35 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Danvers clay loam, 4 to 8 percent slopes | 5K | Well drained | C | Somewhat limited | Very limited |
| Windham-Lap-Rock outcrop complex, 15 to 35 percent slopes | 5K | Well drained | B | Very limited | Very limited |
| Worock-Loberg complex, 15 to 35 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Braziel-Tolbert complex, 15 to 35 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Helmville cobbly loam, cool, 15 to 35 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Trapps gravelly loam, 35 to 60 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Tibson gravelly loam, 15 to 35 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Libeg channery loam, 15 to 35 percent slopes | 4K | Well drained | B | Very limited | Very limited |
| Winspect gravelly loam, 15 to 35 percent slopes | 4K | Well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 95% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.
Septic Systems
About 100% 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.