Channel Islands Area, California, Parts of Santa Barbara and Los Angeles Counties
The most common soil here is Windage, on about 5% of the land: a loam, a balanced mix that crumbles in your hand. Spinnaker and Masthead come next.
About 78% of the land drains well.
USDA rates 90% of the land very limited for a standard septic drain field, and 84% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: bedrock lies within 40 inches under 82% 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 Channel Islands Area, California, Parts of Santa Barbara and Los Angeles Counties, 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 D (very slow infiltration, high 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 Channel Islands Area, California, Parts of Santa Barbara and Los Angeles Counties. 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 |
|---|---|---|---|---|---|
| Rock outcrop-Spinnaker-Topdeck complex, 30 to 80 percent slopes | 11K | D | Not rated | Not rated | |
| Dewpoint-Masthead-Coastwise complex, 20 to 55 percent slopes | 9K | Well drained | D | Very limited | Very limited |
| Masthead-Coastwise-Dewpoint complex, 20 to 55 percent slopes | 9K | Well drained | D | Very limited | Very limited |
| Windage-Typic Xerorthents-Buoy complex 30 to 75 percent slopes | 9K | Well drained | C | Very limited | Very limited |
| Spinnaker-Starboard-Rock outcrop complex, 30 to 75 percent | 8K | Somewhat excessively drained | D | Very limited | Very limited |
| Oboship-Nauti-Bosun complex, 50 to 75 percent slopes | 7K | Well drained | B | Very limited | Very limited |
| Ahoy-Hawser complex, 2 to 30 percent slopes | 7K | Moderately well drained | C | Very limited | Very limited |
| Fantail, thin surface-Forestay-Fantail association, 20 to 75 percent slopes | 7K | Well drained | C | Very limited | Very limited |
| Typic Durixerolls, 5 to 15 percent slopes | 6K | Well drained | D | Somewhat limited | Very limited |
| Windage-Hawser-Typic Haploxeralfs complex 30 to 65 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Ustalfs-Rock outcrop complex, 30 to 100 percent slopes | 5K | Well drained | D | Very limited | Very limited |
| Windage-Buoy complex 30 to 50 percent slopes | 5K | Well drained | C | Very limited | Very limited |
| Masthead-Coastwise-Typic Haploxeralfs complex, 45 to 75 percent slopes | 4K | Well drained | D | Very limited | Very limited |
| Buoy-Rock outcrop-Ballast complex, 30 to 75 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Rock outcrop | 4K | D | Not rated | Not rated | |
| Lodestone-Typic Xerorthents-Windage complex, 25 to 60 percent slopes | 4K | Moderately well drained | D | Very limited | Very limited |
| Eelcove-Sanclemente-Ustalfs association, 2 to 75 percent slopes | 4K | Well drained | D | Very limited | Very limited |
| Shoba-Thirst-Rock outcrop association, 2 to 30 percent slopes | 3K | Well drained | D | Very limited | Very limited |
| Nauti-Flyer-Marpol complex, 25 to 55 percent slopes | 3K | Well drained | C | Very limited | Very limited |
| Fiale-Tongva-Topdeck association, 15 to 60 percent slopes | 3K | Moderately well drained | D | 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 84% 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 90% 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.