San Luis Obispo County, California, Carrizo Plain Area
The most common soil here is Panoza, on about 8% of the land: a loam, a balanced mix that crumbles in your hand. Beam and Balcom come next.
About 91% of the land drains well.
USDA rates 97% of the land very limited for a standard septic drain field, and 74% 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 65% 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 Luis Obispo County, California, Carrizo Plain Area, 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 Inceptisols — young soils with minimal horizon development but more than Entisols. 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, Carrizo Plain Area. 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 |
|---|---|---|---|---|---|
| Balcom-Nacimiento complex, 30 to 50 percent slopes | 30K | Well drained | C | Very limited | Very limited |
| Beam-Panoza-Hillbrick complex, 50 to 75 percent slopes | 27K | Well drained | D | Very limited | Very limited |
| Padres sandy loam, 2 to 9 percent slopes | 24K | Well drained | B | Not limited | Very limited |
| Seaback-Panoza-Jenks complex, 15 to 30 percent slopes | 22K | Well drained | C | Very limited | Very limited |
| Polonio clay loam, 2 to 9 percent slopes | 22K | Well drained | C | Somewhat limited | Very limited |
| Balcom-Nacimiento complex, 15 to 30 percent slopes | 21K | Well drained | C | Very limited | Very limited |
| Beam-Panoza-Hillbrick complex, 30 to 50 percent slopes | 18K | Well drained | D | Very limited | Very limited |
| Panoza-Beam complex, 15 to 30 percent slopes | 17K | Well drained | C | Very limited | Very limited |
| Arbuckle sandy loam, 30 to 50 percent slopes | 16K | Well drained | C | Very limited | Very limited |
| San Timoteo-San Andreas-Bellyspring complex, 30 to 50 percent slopes | 15K | Well drained | B | Very limited | Very limited |
| Wasioja-Polonio complex, 2 to 5 percent slopes | 15K | Well drained | C | Somewhat limited | Very limited |
| Tajea-Saltos complex, 30 to 50 percent slopes | 12K | Well drained | C | Very limited | Very limited |
| Chicote complex, 0 to 2 percent slopes | 10K | Moderately well drained | D | Very limited | Very limited |
| Kilmer-Hillbrick complex, 15 to 50 percent slopes, MLRA 15 | 10K | Well drained | C | Very limited | Very limited |
| Panoza-Beam complex, 30 to 50 percent slopes | 10K | Well drained | C | Very limited | Very limited |
| Lithic Torriorthents-Semper-Rock outcrop complex, 50 to to 75 percent slopes | 10K | Well drained | D | Very limited | Very limited |
| Kilmer-Nacimiento-Aido complex, 30 to 60 percent slopes | 9K | Well drained | C | Very limited | Very limited |
| Balcom loam, 50 to 75 percent slopes | 9K | Well drained | C | Very limited | Very limited |
| Yeguas-Pinspring complex, 0 to 2 percent slopes | 9K | Well drained | C | Not limited | Very limited |
| Yeguas-Pinspring complex, 2 to 5 percent slopes | 9K | Well drained | C | Not 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 74% 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 97% 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.