San Luis Obispo County, California, Coastal Part
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 San Luis Obispo County, California, Coastal Part.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Rock outcrop-Lithic Haploxerolls complex, 30 to 75 percent slopes | 29K | D | Very limited | Very limited | |
| Santa Lucia channery clay loam, 50 to 75 percent slopes, MLRA 15 | 25K | Well drained | C | Very limited | Very limited |
| Lopez very shaly clay loam, 30 to 75 percent slopes | 25K | Somewhat excessively drained | D | Very limited | Very limited |
| Lompico-McMullin loams, 30 to 75 percent slopes | 20K | Well drained | C | Very limited | Very limited |
| Los Osos-Lodo complex, 30 to 75 percent slopes | 20K | Well drained | D | Very limited | Very limited |
| Diablo-Lodo complex, 15 to 50 percent slopes | 18K | Well drained | C | Very limited | Very limited |
| Gazos-Lodo clay loams, 30 to 50 percent slopes | 15K | Well drained | C | Very limited | Very limited |
| Diablo and Cibo clays, 30 to 50 percent slopes | 14K | Well drained | C | Very limited | Very limited |
| Oceano sand, 0 to 9 percent slopes | 14K | Excessively drained | A | Not limited | Very limited |
| Diablo and Cibo clays, 15 to 30 percent slopes | 13K | Well drained | C | Very limited | Very limited |
| Dune land | 13K | Excessively drained | Very limited | Very limited | |
| Los Osos-Diablo complex, 30 to 50 percent slopes | 12K | Well drained | D | Very limited | Very limited |
| Obispo-Rock outcrop complex, 15 to 75 percent slopes | 12K | Well drained | D | Very limited | Very limited |
| Henneke-Rock outcrop complex, 15 to 75 percent slopes | 11K | D | Very limited | Very limited | |
| Santa Lucia channery clay loam, 30 to 50 percent slopes, MLRA 15 | 10K | Well drained | D | Very limited | Very limited |
| Gaviota fine sandy loam, 15 to 50 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Los Osos loam, 30 to 50 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Cropley clay, 2 to 9 percent slopes, MLRA 14 | 10K | Moderately well drained | C | Very limited | Very limited |
| Lodo-Rock outcrop complex, 30 to 75 percent slopes | 9K | Somewhat excessively drained | D | Very limited | Very limited |
| Corducci and Typic Xerofluvents, 0 to 5 percent slopes, occasionally flooded, MLRA 14 | 8K | Somewhat excessively drained | A | Very limited | Very limited |
What This Means
Building & Foundations
About 95% 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 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.