Soil series profile

McCarthy soil series

McCarthy is a well drained soil with a sandy loam surface, mapped on 206,382 acres in 8 counties in CA. Hydrologic group B.

#1754 by mapped area medial-skeletal Andic Xerumbrepts (Inceptisols)

Drainage class: Well drained
Hydrologic group: B
Typical topsoil pH: 6.1
Mapped area: 206k

Typical McCarthy 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 McCarthy horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–16 in (H1)	Sandy loam	6.1	10%	67%	6%
16–28 in (H2)	Very gravelly sandy loam	6.1	19%	66%	1.35%
28–32 in (H3)	Weathered bedrock	Not reported	Not reported	Not reported	Not reported

Representative values from the most extensive McCarthy map unit (McCarthy sandy loam, 30 to 50 percent slopes, survey area CA645). 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 McCarthy soil means for gardens, lawns and septic systems

For gardens

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

Loamy topsoil (loam, silt loam and similar) covers 98% of mapped McCarthy acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is gravelly sandy loam (47% of mapped McCarthy acres).

99% of mapped McCarthy acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

Most land is in hydrologic groups B and C, where rain soaks in at a moderate pace.

For a septic system

For conventional septic absorption fields, NRCS rates 98% of the acres in mapped McCarthy soils very limited, 0% somewhat limited and 0% 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.

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 McCarthy soil is found

Mapped acres

McCarthy is mapped in California.

Counties with the most mapped McCarthy soil
County	Acres	Share of county land
El Dorado County, CA	58,441	5.7%
Tehama County, CA	49,521	2.6%
Nevada County, CA	37,099	2.7%
Shasta County, CA	29,364	1.6%
Placer County, CA	23,820	4.3%
Amador County, CA	7,611	2.1%
Butte County, CA	44	0.0%
Sierra County, CA	29	0.0%

Septic absorption fields

NRCS rating, share of McCarthy acres

Not limited 0%

Somewhat limited 0%

Very limited 98%

Not rated 2%

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

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Septic tank absorption field rating across mapped McCarthy acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	97.8%
Not rated	2.2%

Drainage, water table and flooding

Share of McCarthy 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 16–53% (median 40%).
Topsoil organic matter: Median 6%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained 99%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Not rated 2%

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

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Drainage class across mapped McCarthy acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	98.5%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	1.5%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 14%

B: moderate infiltration 83%

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 McCarthy acres. Scale 0 to 100% of mapped land.

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Hydrologic soil group across mapped McCarthy acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	14.2%
B: moderate infiltration	82.6%
C: slow infiltration	1.1%
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	2.2%

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 McCarthy (component kind "Series") in SSURGO: 206,382 acres.
Method: Shares are by mapped acres of McCarthy components. The profile comes from the single largest McCarthy component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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