Nevada County Area, California
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 Nevada County Area, California.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Boomer, hard bedrock - Rock outcrop complex, 5 to 30 percent slopes | 19K | Well drained | C | Very limited | Very limited |
| Josephine-Mariposa complex, 15 to 50 percent slopes, eroded | 17K | Well drained | B | Very limited | Very limited |
| Boomer, hard bedrock - Rock outcrop complex, 15 to 60 percent slopes | 15K | Well drained | C | Very limited | Very limited |
| Auburn-Rock outcrop complex, 2 to 30 percent slopes | 15K | Well drained | C | Very limited | Very limited |
| Secca-Rock outcrop complex, 2 to 50 percent slopes | 14K | Moderately well drained | C | Very limited | Very limited |
| Sites very stony loam, 15 to 50 percent slopes | 11K | Well drained | C | Very limited | Very limited |
| Sobrante-Rock outcrop complex, 2 to 30 percent slopes | 9K | Well drained | C | Very limited | Very limited |
| Cohasset cobbly loam, 5 to 30 percent slopes | 8K | Well drained | C | Very limited | Very limited |
| Musick sandy loam, 15 to 50 percent slopes | 8K | Well drained | C | Very limited | Very limited |
| Hoda sandy loam, 15 to 50 percent slopes | 8K | Well drained | C | Very limited | Very limited |
| Auburn-Rock outcrop complex, 30 to 50 percent slopes | 7K | Well drained | D | Very limited | Very limited |
| Placer diggings | 6K | Very limited | Very limited | ||
| Mariposa-Josephine complex, 50 to 75 percent slopes, eroded | 6K | Well drained | C | Very limited | Very limited |
| Sites silt loam, 15 to 30 percent slopes, N low montane | 6K | Well drained | C | Very limited | Very limited |
| Aiken loam, 9 to 15 percent slopes, high precip | 5K | Well drained | C | Somewhat limited | Very limited |
| Cohasset cobbly loam, 15 to 50 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Aiken loam, 2 to 9 percent slopes, N Low-Mid Montane | 5K | Well drained | C | Not limited | Very limited |
| Rock land | 5K | D | Very limited | Very limited | |
| Ahwahnee-Rock outcrop complex, 15 to 30 percent slopes | 4K | Well drained | B | Very limited | Very limited |
| Tailings | 4K | Very limited | Very limited |
What This Means
Building & Foundations
About 94% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, flood-prone areas. 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.