Madison County Area, Montana
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 Madison County Area, Montana.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Oro Fino-Poin complex, 15 to 45 percent slopes | 109K | Well drained | B | Very limited | Very limited |
| Sebud-Hapgood-Rock outcrop complex, 25 to 60 percent slopes | 60K | Well drained | B | Very limited | Very limited |
| Nuley-Rock outcrop complex, 8 to 35 percent slopes | 55K | Well drained | B | Very limited | Very limited |
| Kalsted sandy loam, 2 to 8 percent slopes | 51K | Well drained | A | Not limited | Not limited |
| Shurley-Rock outcrop complex, 25 to 60 percent slopes | 43K | Well drained | A | Very limited | Very limited |
| Varney clay loam, 2 to 8 percent slopes | 38K | Well drained | C | Not limited | Somewhat limited |
| Musselshell-Amesha, bedrock substratum, complex, cool, 8 to 25 percent slopes | 35K | Well drained | B | Very limited | Very limited |
| Shurley-Rentsac-Rock outcrop complex, 8 to 35 percent slopes | 35K | Well drained | D | Very limited | Very limited |
| Musselshell loam, cool, 2 to 8 percent slopes | 33K | Well drained | B | Not limited | Somewhat limited |
| Pensore-Crago, cool-Rock outcrop complex, 25 to 75 percent slopes | 33K | Well drained | D | Very limited | Very limited |
| Crago gravelly loam, cool, 0 to 8 percent slopes | 32K | Well drained | B | Not limited | Somewhat limited |
| Hanson channery loam, 8 to 45 percent slopes | 28K | Well drained | B | Very limited | Very limited |
| Musselshell-Crago complex, cool, 2 to 8 percent slopes | 28K | Well drained | B | Not limited | Somewhat limited |
| Crago-Scravo complex, cool, 15 to 45 percent slopes | 28K | Well drained | B | Very limited | Very limited |
| Shadow complex, warm, 45 to 70 percent slopes | 27K | Somewhat excessively drained | A | Very limited | Very limited |
| Whitore-Rock outcrop complex, 25 to 70 percent slopes | 26K | Well drained | B | Very limited | Very limited |
| Rochester-Rock outcrop complex, 35 to 70 percent slopes | 25K | Excessively drained | A | Very limited | Very limited |
| Brocko silt loam, cool, 2 to 12 percent slopes | 25K | Well drained | B | Not limited | Somewhat limited |
| Trimad cobbly loam, 15 to 45 percent slopes | 25K | Well drained | B | Very limited | Very limited |
| Sebud-Hapgood complex, 8 to 45 percent slopes | 24K | Well drained | B | Very limited | Very limited |
What This Means
Building & Foundations
About 72% 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 72% 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.