Amador Area, California

Survey Area CA628• California

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 Amador Area, 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
Auburn very rocky silt loam, 3 to 31 percent slopes	23K	Well drained	D	Very limited	Very limited
Mariposa very rocky loam, 31 to 51 percent slopes	12K	Well drained	C	Very limited	Very limited
Exchequer very rocky silt loam, 31 to 51 percent slopes	12K	Somewhat excessively drained	D	Very limited	Very limited
Exchequer and Auburn very rocky loams, 3 to 31 percent slopes	10K	Well drained	D	Very limited	Very limited
Rock land	10K	Excessively drained	D	Very limited	Very limited
Firebrick-Mokelumne complex, 2 to 30 percent slopes	9K	Well drained	D	Very limited	Very limited
Josephine very rocky loam, 16 to 51 percent slopes	8K	Well drained	C	Very limited	Very limited
Auburn silt loam, 0 to 31 percent slopes	7K	Well drained	D	Very limited	Very limited
Exchequer and Auburn very rocky loams, 31 to 51 percent slopes	6K	Somewhat excessively drained	D	Very limited	Very limited
Amador sandy loam, 2 to 15 percent slopes	6K	Well drained	D	Very limited	Very limited
Red Bluff-Mokelumne complex, 3 to 15 percent slopes	6K	Well drained	C	Not limited	Very limited
Exchequer very rocky silt loam, 3 to 31 percent slopes	6K	Somewhat excessively drained	D	Very limited	Very limited
Auburn very rocky silt loam, 31 to 51 percent slopes	6K	Well drained	D	Very limited	Very limited
Mariposa very rocky loam, 51 to 85 percent slopes	6K	Well drained	D	Very limited	Very limited
Cohasset very cobbly loam, 16 to 51 percent slopes	5K	Well drained	B	Very limited	Very limited
Water	5K		D	Not rated	Not rated
Sites very rocky loam, 16 to 51 percent slopes	4K	Well drained	C	Very limited	Very limited
Argonaut very rocky loam, 3 to 31 percent slopes	4K	Moderately well drained	D	Very limited	Very limited
Mariposa-Sites complex, 16 to 51 percent slopes	4K	Well drained	C	Very limited	Very limited
Mined land-Anthraltic Xerorthents complex, 1 to 15 percent slopes	4K			Not rated	Not rated

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.

Andisols

Volcanic ash soils — light, porous, and fertile. Excellent drainage, but low density can complicate foundations.

What This Means

Building & Foundations

About 90% 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.