Soil series profile

Carrizo soil series

Carrizo is a excessively drained soil with a very gravelly sand surface, mapped on 755,645 acres in 11 counties across 3 states. Hydrologic group A.

#294 by mapped area sandy-skeletal Typic Torriorthents (Entisols)

Drainage class: Excessively drained
Hydrologic group: A
Typical topsoil pH: 7.9
Mapped area: 756k

Typical Carrizo 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).

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Typical Carrizo horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–3 in (A)	Very gravelly sand	7.9	3%	96%	0.25%
3–64 in (C)	Stratified very gravelly coarse sand to very gravelly sand	7.9	3%	91%	0.25%

Representative values from the most extensive Carrizo map unit (Carrizo very gravelly sand, survey area AZ649). 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 Carrizo soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Carrizo soils is moderately alkaline: pH 7.9 (most land between 7.8 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 51% of mapped Carrizo acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is extremely gravelly sandy loam (37% of mapped Carrizo acres).

98% of mapped Carrizo acres is excessively or somewhat excessively drained: water moves through fast, so gardens need more frequent watering in dry spells.

For lawns and yards

97% of mapped acres is in hydrologic group A, where water soaks in fast. Lawns there dry out quickly; deeper, less frequent watering and organic matter help.

For a septic system

For conventional septic absorption fields, NRCS rates 96% of the acres in mapped Carrizo soils very limited, 1% somewhat limited and 1% not limited (2% 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.

Flooding is mapped on 78% of the acres (45% occasional, 3% frequent).

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 Carrizo soil is found

Mapped acres

Carrizo is mapped in Arizona, California and Nevada.

Counties with the most mapped Carrizo soil
County	Acres	Share of county land
Maricopa County, AZ	242,988	3.9%
San Bernardino County, CA	139,868	2.6%
Mohave County, AZ	88,624	1.0%
Riverside County, CA	78,335	2.6%
Clark County, NV	54,381	1.1%
Yuma County, AZ	27,232	1.2%
San Diego County, CA	26,035	1.1%
La Paz County, AZ	22,450	0.8%
Pinal County, AZ	9,938	0.3%
Pima County, AZ	6,911	0.1%
Imperial County, CA	496	0.0%

Septic absorption fields

NRCS rating, share of Carrizo acres

Not limited 1%

Somewhat limited 1%

Very limited 96%

Not rated 2%

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

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Septic tank absorption field rating across mapped Carrizo acres.
Category	Share of acres
Not limited	1.0%
Somewhat limited	1.0%
Very limited	96.2%
Not rated	1.8%

Drainage, water table and flooding

Share of Carrizo acres

Depth to seasonal high water table: None reported within about 6.5 feet (median where reported).
Flooding: Mapped as flooding on 78% of acres (45% occasional, 3% frequent).
Slope: Typically 2–8% (median 3%).
Topsoil organic matter: Median 0.2%.

Drainage class

Excessively drained 92%

Somewhat excessively drained 6%

Well drained 0%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Not rated 2%

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

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Drainage class across mapped Carrizo acres.
Category	Share of acres
Excessively drained	92.4%
Somewhat excessively drained	5.8%
Well drained	0.0%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	1.8%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 97%

B: moderate infiltration <1%

C: slow infiltration 1%

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 2%

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

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Hydrologic soil group across mapped Carrizo acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	96.9%
B: moderate infiltration	0.3%
C: slow infiltration	1.0%
D: very slow infiltration (clayey, shallow or wet)	0.0%
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	1.8%

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 Carrizo (component kind "Series") in SSURGO: 755,645 acres.
Method: Shares are by mapped acres of Carrizo components. The profile comes from the single largest Carrizo component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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