Pinnacles National Monument, 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 Pinnacles National Monument, California.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Ordeal-Longsfolly-Passion complex, 9 to 50 percent slopes | 4K | Somewhat excessively drained | A | Very limited | Very limited |
| Backdoor-Tuborcio complex, 20 to 70 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Ordeal-Passion-Badlands association, 50 to 100 percent slopes | 3K | Somewhat excessively drained | B | Very limited | Very limited |
| Backdoor-Tuborcio complex, 35 to 50 percent slopes | 2K | Well drained | C | Very limited | Very limited |
| Ordeal-Tuborcio-Passion complex, 20 to 50 percent slopes | 2K | Somewhat excessively drained | B | Very limited | Very limited |
| Chalone-Knuckle-Firstsister complex, 50 to 70 percent slopes | 2K | Well drained | C | Very limited | Very limited |
| Knuckle-Burgundy-Argixerolls complex, 20 to 70 percent slopes | 2K | Well drained | D | Very limited | Very limited |
| Rock outcrop-Highpeaks-Burgundy complex, 35 to 100 percent slopes | 1K | Well drained | D | Very limited | Very limited |
| Chalone-Firstsister-Highpeaks complex, 50 to 70 percent slopes | 1K | Well drained | C | Very limited | Very limited |
| Tuborcio sandy loam, 35 to 50 percent slopes | 790 | Well drained | C | Very limited | Very limited |
| Rock outcrop-Highpeaks-Chalone complex, 35 to 50 percent slopes | 730 | Well drained | D | Very limited | Very limited |
| Chalone-Knuckle-Rock outcrop complex, 35 to 50 percent slopes | 651 | Well drained | D | Very limited | Very limited |
| Argixerolls-Rock outcrop-Chalone complex, 35 to 50 percent slopes | 623 | Well drained | C | Very limited | Very limited |
| Casino-Argixerolls complex, 50 to 70 percent slopes | 436 | Moderately well drained | D | Very limited | Very limited |
| Highpeaks-Rock outcrop complex, 35 to 50 percent slopes | 282 | Well drained | D | Very limited | Very limited |
| Pinnacles coarse sandy loam, 5 to 30 percent slopes | 267 | Well drained | C | Very limited | Very limited |
| Toags-Oxyaquic Haploxerolls-Riverwash complex, 0 to 2 percent slopes | 254 | Somewhat excessively drained | A | Not limited | Very limited |
| Pinnacles coarse sandy loam, 30 to 75 percent slopes | 240 | Well drained | D | Very limited | Very limited |
| Teapot-Rock outcrop complex, 35 to 50 percent slopes | 191 | Well drained | B | Very limited | Very limited |
| Tuborcio loam, 2 to 20 percent slopes | 185 | Well drained | C | Somewhat limited | Very limited |
What This Means
Building & Foundations
About 98% 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.