Soil series profile

Calleguas soil series

Calleguas is a well drained soil with a clay loam surface, mapped on 58,687 acres in 8 counties in CA. Hydrologic group D.

#5296 by mapped area loamy Typic Xerorthents (Entisols)

Drainage class: Well drained
Hydrologic group: D
Typical topsoil pH: 8.2
Mapped area: 59k

Typical Calleguas profile

Texture and pH by depth

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 Calleguas horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–7 in (A1)	Clay loam	8.2	30%	35%	0.75%
7–11 in (A2)	Clay loam	8.2	30%	35%	0.75%
11–15 in (A3)	Very channery clay loam	8.2	30%	35%	0.75%
15–59 in (Cr)	Bedrock	Not reported	Not reported	Not reported	Not reported

Representative values from the most extensive Calleguas map unit (Calleguas clay loam, 50 to 75 percent slopes, eroded, survey area CA678). Other map units of this series vary within the series range.

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

What this means

What Calleguas soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Calleguas soils is moderately alkaline: pH 8.2 (most land between 7.9 and 8.2). Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).

Loamy topsoil (loam, silt loam and similar) covers 85% of mapped Calleguas acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is clay loam (56% of mapped Calleguas acres).

86% of mapped Calleguas acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

On 85% 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 85% of the acres in mapped Calleguas soils very limited, 0% somewhat limited and 0% not limited (15% 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 Calleguas soil is found

Mapped acres

Calleguas is mapped in California.

Counties with the most mapped Calleguas soil
County	Acres	Share of county land
Orange County, CA	29,946	6.0%
San Luis Obispo County, CA	16,691	1.0%
Ventura County, CA	5,735	0.9%
Kern County, CA	5,698	0.1%
Los Angeles County, CA	436	0.0%
San Diego County, CA	138	0.0%
San Bernardino County, CA	41	0.0%
Riverside County, CA	2	0.0%

Septic absorption fields

NRCS rating, share of Calleguas acres

Not limited 0%

Somewhat limited 0%

Very limited 85%

Not rated 15%

Septic tank absorption field rating across mapped Calleguas acres. Scale 0 to 100% of mapped land.

Show as a table

Septic tank absorption field rating across mapped Calleguas acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	85.1%
Not rated	14.9%

Drainage, water table and flooding

Share of Calleguas 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 29–63% (median 63%).
Topsoil organic matter: Median 0.8%.

Drainage class

Excessively drained 0%

Somewhat excessively drained <1%

Well drained 85%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Not rated 14%

Drainage class across mapped Calleguas acres. Scale 0 to 100% of mapped land.

Show as a table

Drainage class across mapped Calleguas acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.6%
Well drained	85.1%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	14.3%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%

B: moderate infiltration 0%

C: slow infiltration 0%

D: very slow infiltration (clayey, shallow or wet) 85%

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 15%

Hydrologic soil group across mapped Calleguas acres. Scale 0 to 100% of mapped land.

Show as a table

Hydrologic soil group across mapped Calleguas acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	0.0%
C: slow infiltration	0.0%
D: very slow infiltration (clayey, shallow or wet)	85.1%
A/D: D as is, A if drained	0.0%
B/D: D as is, B if drained	0.0%
C/D: D as is, C if drained	0.0%
Not rated	14.9%

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 Calleguas (component kind "Series") in SSURGO: 58,687 acres.
Method: Shares are by mapped acres of Calleguas components. The profile comes from the single largest Calleguas component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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