Nevada County Area, California
The most common soil here is Boomer, on about 9% of the land: a gravelly loam, a balanced mix that crumbles in your hand. Sites and Auburn come next.
About 89% of the land drains well.
USDA rates 99% of the land very limited for a standard septic drain field, and 83% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 1% of the land floods occasionally or more, and bedrock lies within 40 inches under 54% of it.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in Nevada County Area, California, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). The most common soil order is Alfisols — moderately leached forest soils with a clay-enriched subsoil. 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. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| 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 |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 83% 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 99% 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.