Orange County and Part of Riverside County, California
The most common soil here is Cieneba, on about 11% of the land: a gravelly loam, a balanced mix that crumbles in your hand. Friant and Myford come next.
About 74% of the land drains well, and 12% stays wet for long stretches.
USDA rates 87% of the land very limited for a standard septic drain field, and 63% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 2% of the land floods occasionally or more, and bedrock lies within 40 inches under 52% 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 Orange County and Part of Riverside 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 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 Orange County and Part of Riverside 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 |
|---|---|---|---|---|---|
| Friant fine sandy loam, 30 to 75 percent slopes | 50K | Well drained | D | Very limited | Very limited |
| Cieneba sandy loam, 30 to 75 percent slopes, eroded | 42K | Somewhat excessively drained | D | Very limited | Very limited |
| Cieneba-Rock outcrop complex, 30 to 75 percent slopes | 37K | Somewhat excessively drained | D | Very limited | Very limited |
| Calleguas clay loam, 50 to 75 percent slopes, eroded | 35K | Well drained | D | Very limited | Very limited |
| Hueneme fine sandy loam, drained | 24K | Poorly drained | A | Not limited | Very limited |
| Myford sandy loam, 2 to 9 percent slopes | 21K | Moderately well drained | C | Somewhat limited | Very limited |
| Metz loamy sand | 21K | Somewhat excessively drained | B | Not limited | Somewhat limited |
| Exchequer-Rock outcrop complex, 30 to 75 percent slopes | 19K | Somewhat excessively drained | D | Very limited | Very limited |
| Rock outcrop-Cieneba complex, 30 to 75 percent slopes | 18K | D | Not rated | Not rated | |
| San Emigdio fine sandy loam, 0 to 2 percent slopes | 16K | Well drained | A | Not limited | Very limited |
| Bolsa silt loam, drained | 14K | Somewhat poorly drained | C | Very limited | Very limited |
| Mocho loam, 0 to 2 percent slopes, warm MAAT, MLRA 19 | 12K | Well drained | B | Not limited | Somewhat limited |
| Alo clay, 15 to 30 percent slopes, dry | 11K | Well drained | D | Very limited | Very limited |
| Alo clay, 30 to 50 percent slopes, warm MAAT, MLRA 20 | 11K | Well drained | D | Very limited | Very limited |
| Chino silty clay loam, drained | 10K | Somewhat poorly drained | C | Very limited | Very limited |
| Metz loamy sand, moderately fine substratum | 9K | Somewhat excessively drained | B | Very limited | Somewhat limited |
| San Emigdio fine sandy loam, moderately fine substratum, 0 to 2 percent slopes | 7K | Well drained | A | Not limited | Very limited |
| Omni clay, drained | 7K | Poorly drained | C | Very limited | Very limited |
| Sorrento clay loam, 0 to 2 percent slopes, warm MAAT, MLRA 19 | 7K | Well drained | C | Somewhat limited | Very limited |
| Sorrento loam, 0 to 2 percent slopes, warm MAAT, MLRA 19 | 6K | Well drained | C | Somewhat 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 63% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 87% 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.