San Mateo Area, California

Survey Area CA637• California

The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate 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 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
Hugo and Josephine sandy loams, very steep	15K	Well drained	A	Very limited	Very limited
Hugo and Josephine loams, very steep	12K	Well drained	B	Very limited	Very limited
Butano loam, very steep	11K	Well drained	C	Very limited	Very limited
Rough broken land	9K	Excessively drained		Very limited	Very limited
Hugo and Josephine sandy loams, very steep, eroded	6K	Well drained	A	Very limited	Very limited
Miramar coarse sandy loam, very steep, eroded	6K	Well drained	C	Very limited	Very limited
Lobitos loam, steep, eroded	5K	Well drained	C	Very limited	Very limited
Gazos loam, very steep, eroded	5K	Well drained	C	Very limited	Very limited
Santa Lucia loam, very steep, eroded	5K	Well drained	C	Very limited	Very limited
Lobitos loam, very steep, eroded	4K	Well drained	C	Very limited	Very limited
Lobitos loam, moderately steep, eroded	3K	Well drained	C	Very limited	Very limited
Santa Lucia loam, steep, eroded	3K	Well drained	C	Very limited	Very limited
Mindego clay loam, very steep	3K	Well drained	C	Very limited	Very limited
Santa Lucia stony loam, very steep, eroded	2K	Well drained	C	Very limited	Very limited
Tierra loam, steep, eroded	2K	Moderately well drained	D	Very limited	Very limited
Santa Lucia loam, moderately steep, eroded	2K	Well drained	C	Very limited	Very limited
Pomponio loam, moderately steep, eroded	2K	Moderately well drained	C	Very limited	Very limited
Hugo and Josephine sandy loams, steep, eroded	2K	Well drained	A	Very limited	Very limited
Tierra loam, moderately steep, eroded	2K	Moderately well drained	D	Very limited	Very limited
Miramar coarse sandy loam, steep, eroded	2K	Well drained	C	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.

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

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.

Vertisols

High-clay soils that shrink and swell dramatically. Fertile but challenging for foundations and septic systems.

What This Means

Building & Foundations

About 100% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes. A geotechnical assessment is recommended before building.

Septic Systems

About 100% 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.