Soil survey area

Yuba County, California

Survey Area CA618• California
The short version

The most common soil here is San Joaquin, on about 12% of the land: a loam, a balanced mix that crumbles in your hand. Sobrante and Sites come next.

About 70% of the land drains well, and 4% stays wet for long stretches; groundwater comes within two feet of the surface under 3% of it.

USDA rates 96% 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: 6% of the land floods occasionally or more, and bedrock lies within 40 inches under 40% 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 ground underfoot

The soils you're most likely standing on

The biggest named soils in Yuba County, California, each drawn five feet deep from its official USDA description, in its recorded colors.

San Joaquin
12% of the area
Loam topsoil · well drained
A balanced mix that crumbles in your hand. The gardener's ideal.
Alfisols
Sobrante
9% of the area
Silt loam topsoil · well drained
Smooth, like flour. Fertile and holds water well.
Alfisols
Sites
8% of the area
Loam topsoil · well drained
A balanced mix that crumbles in your hand. The gardener's ideal.
Ultisols
Auburn
7% of the area
Silt loam topsoil · well drained
Smooth, like flour. Fertile and holds water well.
Inceptisols
Surnuf
3% of the area
Well drained
Alfisols
Redding
3% of the area
Gravelly loam topsoil · moderately well drained
A balanced mix that crumbles in your hand. The gardener's ideal.
Alfisols

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 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 Yuba County, California. Search your address to find the exact soil composition, drainage, and series details at your specific location.

Soil Map UnitAcresDrainageHydro GroupDwellingsSeptic
San Joaquin loam, 0 to 1 percent slopes 56K Moderately well drainedDVery limitedVery limited
Sobrante-Auburn complex, 3 to 8 percent slopes 21K Well drainedCVery limitedVery limited
Conejo loam, 0 to 1 percent slopes, MLRA 17 10K Well drainedCVery limitedVery limited
Sites silt loam, 9 to 15 percent slopes, N low montane 9K Well drainedCSomewhat limitedVery limited
Redding gravelly loam, 0 to 8 percent slopes, MLRA 17 9K Moderately well drainedDVery limitedVery limited
Sites silt loam, 15 to 30 percent slopes, N low montane 9K Well drainedCVery limitedVery limited
Sobrante-Auburn complex, 8 to 15 percent slopes 9K Well drainedCVery limitedVery limited
Sobrante-Auburn complex, gravelly, 8 to 15 percent slopes 9K Well drainedCSomewhat limitedVery limited
Kimball loam, 0 to 1 percent slopes 8K Well drainedDVery limitedVery limited
WATER 7K DNot ratedNot rated
Hollenbeck silty clay loam, 0 to 1 percent slopes 6K Moderately well drainedCVery limitedVery limited
DUMPS, MINE TAILINGS 6K Very limitedVery limited
Sobrante-Timbuctoo complex, 15 to 30 percent slopes 6K Well drainedCVery limitedVery limited
Surnuf cobbly loam, 15 to 30 percent slopes 6K Well drainedCVery limitedVery limited
Sobrante-Auburn complex, gravelly, 15 to 30 percent slopes 6K Well drainedCVery limitedVery limited
Sobrante-Timbuctoo complex, 30 to 50 percent slopes 5K Well drainedCVery limitedVery limited
Argonaut-Auburn complex, 3 to 8 percent slopes 5K Well drainedCSomewhat limitedVery limited
Chawanakee-Chaix-Hotaw complex, 30 to 75 percent slopes 5K Somewhat excessively drainedDVery limitedVery limited
Sites gravelly loam, 30 to 50 percent slopes 5K Well drainedCVery limitedVery limited
Holland-Hoda-Hotaw complex, 30 to 50 percent slopes 4K Well drainedCVery limitedVery 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.

Alfisols
Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.
Ultisols
Strongly weathered clay soils of the Southeast. Acidic and naturally low in nutrients. Clay subsoil can slow drainage.
Inceptisols
Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.
Entisols
Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

What This Means

Building & Foundations

About 84% 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 96% 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.

Look Up a Specific Address

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