San Mateo County, Eastern Part, and San Francisco County, California

Survey Area CA689• 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 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 Mateo County, Eastern Part, and San Francisco 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
Water	105K		D	Not rated	Not rated
Urban land-Orthents, reclaimed complex, 0 to 2 percent slopes	18K		D	Not limited	Not limited
Alambique-McGarvey complex, 30 to 75 percent slopes	13K	Well drained	C	Very limited	Very limited
Urban land	13K		D	Not limited	Not limited
Orthents, cut and fill-Urban land complex, 5 to 75 percent slopes	12K	Well drained		Very limited	Very limited
Urban land-Orthents, cut and fill complex, 0 to 5 percent slopes	10K		D	Not limited	Not limited
Urban land-Orthents, cut and fill complex, 5 to 75 percent slopes	9K		D	Very limited	Very limited
Barnabe-Candlestick complex, 30 to 75 percent slopes	8K	Well drained	D	Very limited	Very limited
Urban land-Orthents, smoothed complex, 5 to 50 percent slopes	8K		D	Very limited	Very limited
Urban land-Sirdrak complex, 2 to 50 percent slopes	6K		D	Very limited	Very limited
Botella-Urban land complex, 0 to 5 percent slopes	6K		C	Somewhat limited	Very limited
Los Gatos loam, 30 to 75 percent slopes, MLRA 15	6K	Well drained	C	Very limited	Very limited
Candlestick-Kron-Buriburi complex, 30 to 75 percent slo pes	5K	Well drained	C	Very limited	Very limited
Orthents, cut and fill, 0 to 15 percent slopes	5K	Well drained		Not limited	Not limited
Fagan loam, 15 to 50 percent slopes	4K	Well drained	C	Very limited	Very limited
Novato clay, 0 to 1 percent slopes ponded	3K	Very poorly drained	C/D	Very limited	Very limited
Reyes clay, 0 to 1 percent slopes	3K	Somewhat poorly drained	C	Very limited	Very limited
Scarper-Miramar complex, 30 to 75 percent slopes	2K	Well drained	B	Very limited	Very limited
Accelerator-Fagan-Urban land complex, 5 to 15 percent s lopes	2K	Well drained	C	Somewhat limited	Very limited
Sirdrak sand, 5 to 50 percent slopes	2K	Somewhat excessively drained	A	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.

Mollisols

Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.

Entisols

Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

What This Means

Building & Foundations

About 33% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.

Septic Systems

About 37% of soils have significant septic limitations, while others are more suitable. A perc test is essential — conditions vary across the area.

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.