What's My Soil

A field guide to the soil under your feet

Soil series profile

Lobitos soil series

Lobitos is a well drained soil with a loam surface, mapped on 17,369 acres in 4 counties in CA. Hydrologic group C.

#11135 by mapped area fine-loamy Typic Argixerolls (Mollisols)

Drainage class
Well drained
79% of mapped acres
Hydrologic group
C
79% of mapped acres
Typical topsoil pH
6.1
slightly acidic · range 6.1–6.1
Mapped area
17k
acres in 4 counties, 1 state

Typical Lobitos profile

Texture and pH by depth

Typical Lobitos soil profile by depth 0 in 10 in 20 in 30 in 0–18 in · H1 · pH 6.1 · 21% clay Loam 18–29 in · H2 · pH 5.8 · 31% clay Channery clay loam 29–34 in · H3 · pH 5.8 · 20% clay Channery loam 34–38 in · H4 Unweathered bedrock
Depth to scale. More strongly shaded layers hold more clay. Horizon names are the soil survey's (A = topsoil, B = subsoil, C = parent material).
Show as a table
Typical Lobitos horizons (representative values)
Depth Texture pH Clay Sand Organic matter
0–18 in (H1) Loam 6.1 21% 42% 2%
18–29 in (H2) Channery clay loam 5.8 31% 35% 0.85%
29–34 in (H3) Channery loam 5.8 20% 42% 0.25%
34–38 in (H4) Unweathered bedrock Not reported Not reported Not reported Not reported

Representative values from the most extensive Lobitos map unit (Lobitos loam, steep, eroded, survey area CA637). Other map units of this series vary within the series range.

Hands holding dark garden soil
Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Lobitos soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Lobitos soils is slightly acidic: pH 6.1, the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers 79% of mapped Lobitos acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is loam (64% of mapped Lobitos acres).

79% of mapped Lobitos acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

On 79% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.

For a septic system

For conventional septic absorption fields, NRCS rates 79% of the acres in mapped Lobitos soils very limited, 0% somewhat limited and 0% not limited (21% not rated, such as urban land, pits or water).

Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.

Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.

Generated from the mapped numbers above using fixed rules, not a site visit. See how these notes are written.

Where Lobitos soil is found

Mapped acres

Lobitos is mapped in California.

Counties with the most mapped Lobitos soil
County Acres Share of county land
San Mateo County, CA 15,552 5.4%
Alameda County, CA 1,817 0.4%
Santa Clara County, CA 1 0.0%
Contra Costa County, CA 0 0.0%

Septic absorption fields

NRCS rating, share of Lobitos acres

Not limited 0%
Somewhat limited 0%
Very limited 79%
Not rated 21%
Septic tank absorption field rating across mapped Lobitos acres. Scale 0 to 100% of mapped land.
Show as a table
Septic tank absorption field rating across mapped Lobitos acres.
CategoryShare of acres
Not limited0.0%
Somewhat limited0.0%
Very limited79.0%
Not rated21.0%

Drainage, water table and flooding

Share of Lobitos acres

Depth to seasonal high water table
None reported within about 6.5 feet (median where reported).
Flooding
Not mapped as flooding on most acres.
Slope
Typically 23–58% (median 36%).
Topsoil organic matter
Median 2%.

Drainage class

Excessively drained 0%
Somewhat excessively drained 0%
Well drained 79%
Moderately well drained 0%
Somewhat poorly drained 0%
Poorly drained 0%
Very poorly drained 0%
Not rated 21%
Drainage class across mapped Lobitos acres. Scale 0 to 100% of mapped land.
Show as a table
Drainage class across mapped Lobitos acres.
CategoryShare of acres
Excessively drained0.0%
Somewhat excessively drained0.0%
Well drained79.0%
Moderately well drained0.0%
Somewhat poorly drained0.0%
Poorly drained0.0%
Very poorly drained0.0%
Not rated21.0%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%
B: moderate infiltration 0%
C: slow infiltration 79%
D: very slow infiltration (clayey, shallow or wet) 0%
A/D: D as is, A if drained 0%
B/D: D as is, B if drained 0%
C/D: D as is, C if drained 0%
Not rated 21%
Hydrologic soil group across mapped Lobitos acres. Scale 0 to 100% of mapped land.
Show as a table
Hydrologic soil group across mapped Lobitos acres.
CategoryShare of acres
A: fast infiltration (mostly sandy or gravelly)0.0%
B: moderate infiltration0.0%
C: slow infiltration79.0%
D: very slow infiltration (clayey, shallow or wet)0.0%
A/D: D as is, A if drained0.0%
B/D: D as is, B if drained0.0%
C/D: D as is, C if drained0.0%
Not rated21.0%

Sources & data dates

Source
USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
Data date
SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
Scope
All map unit components named Lobitos (component kind "Series") in SSURGO: 17,369 acres.
Method
Shares are by mapped acres of Lobitos components. The profile comes from the single largest Lobitos component. Full methodology.

Independent reference site. No government affiliation or endorsement.

Full narrative description: USDA Official Soil Series Description for Lobitos.