Treasure 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 Treasure County, Montana.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Midway-Bainville complex | 79K | Well drained | D | Very limited | Very limited |
| Midway clay loam, 15 to 35 percent slopes | 41K | Well drained | D | Very limited | Very limited |
| Midway-Shale outcrop complex, 4 to 35 percent slopes | 29K | Well drained | D | Very limited | Very limited |
| Midway-Nihill gravelly loam | 24K | Well drained | D | Very limited | Very limited |
| Pierre-Lismas clays, saline-Alkali | 24K | Well drained | D | Very limited | Very limited |
| Hoven and McKenzie soils | 20K | Well drained | D | Very limited | Very limited |
| McRae-Bainville loams, 8 to 20 percent slopes | 20K | Well drained | B | Somewhat limited | Somewhat limited |
| Bainville loam, 15 to 35 percent slopes | 18K | Well drained | D | Very limited | Very limited |
| Bainville-Midway complex, 15 to 35 percent slopes | 16K | Well drained | D | Very limited | Very limited |
| Bainville-Shale outcrop complex | 16K | Well drained | D | Very limited | Very limited |
| Havre loam | 13K | Well drained | B | Very limited | Somewhat limited |
| Pierre-Lismas clays | 12K | Well drained | D | Very limited | Very limited |
| Marias clays, fans, saline-alkali | 12K | Well drained | D | Very limited | Very limited |
| Marias-Hoven clays, saline | 12K | Well drained | D | Very limited | Very limited |
| Lismas-Pierre clays, saline-Alkali | 12K | Well drained | D | Very limited | Very limited |
| Lismas-Midway complex | 11K | Well drained | D | Very limited | Very limited |
| Bainville loam, 8 to 15 percent slopes | 11K | Well drained | C | Somewhat limited | Very limited |
| Blacksheep-Twilight fine sandy loams, 15 to 40 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Cushman loam, 4 to 8 percent slopes | 9K | Well drained | C | Somewhat limited | Very limited |
| Fort Collins loam, 4 to 8 percent slopes | 9K | Well drained | B | Not limited | Somewhat limited |
What This Means
Building & Foundations
About 87% 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 89% 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.