San Benito County, California
The most common soil here is San Benito, on about 10% of the land: a clay loam, firm and a little sticky. Vallecitos and Sheridan come next.
About 82% of the land drains well, and 4% stays wet for long stretches.
USDA rates 94% of the land very limited for a standard septic drain field, and 89% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 3% of the land floods occasionally or more, and bedrock lies within 40 inches under 55% 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 San Benito County, 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 D (very slow infiltration, high runoff). The most common soil order is Mollisols — grassland soils with a thick, dark, fertile topsoil rich in organic matter. 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 Benito County, 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 |
|---|---|---|---|---|---|
| Sedimentary rock land | 66K | D | Very limited | Very limited | |
| San Benito clay loam, 30 to 50 percent slopes, eroded, MLRA 15 | 57K | Well drained | C | Very limited | Very limited |
| Gaviota rocky loam, 15 to 50 percent slopes, eroded | 31K | Somewhat excessively drained | D | Very limited | Very limited |
| Vallecitos rocky loam, 30 to 50 percent slopes, eroded | 31K | Well drained | D | Very limited | Very limited |
| Sheridan coarse sandy loam, 30 to 75 percent slopes, severely eroded | 30K | Well drained | B | Very limited | Very limited |
| Badland | 30K | D | Very limited | Very limited | |
| San Benito clay loam, 15 to 30 percent slopes, eroded, MLRA 15 | 26K | Well drained | B | Very limited | Very limited |
| Vallecitos loam, 30 to 50 percent slopes, eroded | 24K | Well drained | D | Very limited | Very limited |
| Kettleman soils, 15 to 50 percent slopes, eroded | 23K | Well drained | A | Very limited | Very limited |
| Cibo cobbly clay, 15 to 75 percent slopes, stony, eroded | 20K | Well drained | D | Very limited | Very limited |
| Diablo clay, 30 to 50 percent slopes, eroded, MLRA 15 | 19K | Well drained | C | Very limited | Very limited |
| Borreguero-Sancarlos-Currymountain association, 20 to 65 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| Diablo clay, 15 to 30 percent slopes, eroded, MLRA 15 | 14K | Well drained | C | Very limited | Very limited |
| Sheridan coarse sandy loam, 30 to 75 percent slopes, eroded | 13K | Well drained | B | Very limited | Very limited |
| Nacimiento loam, 30 to 75 percent slopes, severely erod ed | 12K | Well drained | D | Very limited | Very limited |
| Gazos clay loam, 30 to 50 percent slopes, eroded | 12K | Well drained | C | Very limited | Very limited |
| Kettleman loam, 15 to 50 percent slopes, eroded | 11K | Well drained | B | Very limited | Very limited |
| Sorrento silty clay loam, 0 to 2 percent slopes, MLRA 14 | 10K | Well drained | C | Somewhat limited | Very limited |
| Vallecitos loam, 30 to 50 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Cieneba gravelly sandy loam, 30 to 75 percent slopes, eroded | 9K | Somewhat excessively 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 89% 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 94% 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.