County soil summary

Soil types in Fresno County, California

The most widespread soils are Ciervo, Cerini and Hanford; the most common drainage class is well drained (49% of the land), and typical topsoil pH is 6.7.

Mapped soil survey data 4.7 million acres of mapped land · 235 named soil series

About 1.7 million acres of Fresno County lie in multi-county soil survey areas (CA740, CA750, CA760) that the soil survey does not split by county. Those acres, often public forest or desert land, are counted in the California totals but not in the figures below.

Well or moderately well drained
72%
of land · state 81%
Typical topsoil pH
6.7
neutral · state 6.7
Septic fields very limited
77%
of land · state 79%
Subject to flooding
21%
of land, any frequency · state 11%

Most common soils in Fresno County

Share of mapped land

A county is a patchwork of many soils. These 8 cover 33% of the mapped land; 235 named soil series are mapped here in all.

Most common soils in Fresno County by share of mapped land
Soil Share of land Drainage Topsoil pH
Rock outcropLand type, not a soil series 12.2% — —
Typic CryorthentsGeneral soil group, not a named series 5.6% — —
UnnamedLand type, not a soil series 3.4% — —
Rock outcrop and rubble landLand type, not a soil series 2.7% — —
Holland familyGeneral soil group, not a named series 2.5% — —
Ciervo 2.4% Moderately well drained 8.2
Cerini 2.3% Well drained 7.7
Hanford 2.2% Well drained 6.7

Drainage and pH for a series are its typical values across all its mapped acres nationwide. A dash means the row is not a soil series.

What this means

What the soils in Fresno County mean for gardens, lawns and septic systems

For your garden

Typical topsoil in Fresno County is neutral: pH 6.7 (most land between 5.0 and 8.2), the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers 48% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is sandy loam (16% of the land).

72% of the land is moderately well to excessively drained, which suits most garden plants.

For your lawn and yard

On 52% of the land, 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 77% of the land in Fresno County very limited, 6% somewhat limited and <1% not limited (17% not rated, such as urban land, pits or water).

That is close to the state as a whole (79% very limited).

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 21% of the land (1% occasional, <1% 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.

Drainage

How long the soil stays wet

The most common drainage class is well drained (49%). 72% of the land is moderately well drained or better, compared with 81% across California.

Excessively drained 7%
Somewhat excessively drained 10%
Well drained 49%
Moderately well drained 6%
Somewhat poorly drained 5%
Poorly drained 2%
Very poorly drained 1%
Not rated 20%
Natural drainage class, share of mapped land in Fresno County. Scale 0 to 100% of mapped land.
Show as a table
Natural drainage class, share of mapped land in Fresno County.
CategoryFresno CountyCalifornia
Excessively drained6.6%7.7%
Somewhat excessively drained10.2%17.6%
Well drained49.0%50.7%
Moderately well drained6.2%4.7%
Somewhat poorly drained4.8%2.5%
Poorly drained2.2%2.0%
Very poorly drained1.2%0.7%
Not rated19.7%14.2%

Septic absorption fields

NRCS rating for conventional drain fields

The rating looks at the soil from 24 to 60 inches deep: permeability, depth to a seasonal water table or bedrock, flooding and slope. “Very limited” means at least one feature is unfavorable enough that a conventional field is hard to make work.

Not limited <1%
Somewhat limited 6%
Very limited 77%
Not rated 17%
Septic tank absorption field rating, share of mapped land in Fresno County. Scale 0 to 100% of mapped land.
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Septic tank absorption field rating, share of mapped land in Fresno County.
CategoryFresno CountyCalifornia
Not limited0.3%4.3%
Somewhat limited6.0%3.6%
Very limited77.3%79.2%
Not rated16.5%12.9%

Rain, runoff and water table

Hydrologic soil group, flooding, seasonal water table

Hydrologic soil group

How fast rain soaks in when the soil is already wet. Group A soaks in fastest, D slowest.

A: fast infiltration (mostly sandy or gravelly) 20%
B: moderate infiltration 12%
C: slow infiltration 23%
D: very slow infiltration (clayey, shallow or wet) 29%
A/D: D as is, A if drained <1%
B/D: D as is, B if drained <1%
C/D: D as is, C if drained 0%
Not rated 16%
Hydrologic soil group, share of mapped land in Fresno County. Scale 0 to 100% of mapped land.
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Hydrologic soil group, share of mapped land in Fresno County.
CategoryFresno CountyCalifornia
A: fast infiltration (mostly sandy or gravelly)19.6%20.5%
B: moderate infiltration11.7%12.5%
C: slow infiltration22.7%22.7%
D: very slow infiltration (clayey, shallow or wet)28.6%30.3%
A/D: D as is, A if drained0.5%0.3%
B/D: D as is, B if drained0.6%0.3%
C/D: D as is, C if drained0.0%0.9%
Not rated16.3%12.6%

Flooding

No flooding 63%
Rare or very rare 20%
Occasional 1%
Frequent or very frequent <1%
Not reported 16%
Most frequent flooding class in any month, share of mapped land in Fresno County. Scale 0 to 100% of mapped land.
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Most frequent flooding class in any month, share of mapped land in Fresno County.
CategoryFresno CountyCalifornia
No flooding63.3%77.1%
Rare or very rare19.6%8.2%
Occasional1.3%1.6%
Frequent or very frequent0.2%1.0%
Not reported15.5%12.1%

Seasonal high water table

Within 18 inches at some time of year 1%
18 inches to 3.3 feet 1%
Deeper than 3.3 feet or none reported 83%
Not reported 14%
Shallowest depth to a saturated zone in any month, share of mapped land in Fresno County. Scale 0 to 100% of mapped land.
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Shallowest depth to a saturated zone in any month, share of mapped land in Fresno County.
CategoryFresno CountyCalifornia
Within 18 inches at some time of year1.4%2.6%
18 inches to 3.3 feet1.0%1.9%
Deeper than 3.3 feet or none reported83.4%86.9%
Not reported14.2%8.6%

Topsoil pH and texture

First mineral layer of each soil

Typical topsoil pH is 6.7 (neutral); 80% of rated land falls between 5.0 and 8.2. Median topsoil organic matter is 1.3%.

Strongly acidic (below 5.5) 12%
Moderately to slightly acidic (5.5–6.4) 18%
Near neutral (6.5–7.3) 21%
Alkaline (7.4 and up) 23%
Not reported 28%
Topsoil pH band, share of mapped land in Fresno County. Scale 0 to 100% of mapped land.
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Topsoil pH band, share of mapped land in Fresno County.
CategoryFresno CountyCalifornia
Strongly acidic (below 5.5)11.6%3.1%
Moderately to slightly acidic (5.5–6.4)18.0%22.8%
Near neutral (6.5–7.3)20.5%25.2%
Alkaline (7.4 and up)22.5%30.6%
Not reported27.5%18.2%

Texture

Sandy 17%
Loamy (loam, silt loam and similar) 48%
Clayey (40%+ clay) 8%
Organic (muck or peat) <1%
Not reported (rock, urban land, etc.) 28%
Topsoil texture group, share of mapped land in Fresno County. Scale 0 to 100% of mapped land.
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Topsoil texture group, share of mapped land in Fresno County.
CategoryFresno CountyCalifornia
Sandy17.1%21.3%
Loamy (loam, silt loam and similar)47.7%56.7%
Clayey (40%+ clay)7.5%3.9%
Organic (muck or peat)0.2%0.2%
Not reported (rock, urban land, etc.)27.5%18.0%

Most common surface textures: sandy loam 16% · unweathered bedrock 11% · coarse sandy loam 8% · loam 8% · clay 7%.

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
Fresno County, California (FIPS 06019): 4,735,613 acres of mapped land, 27,548 acres of open water excluded. State comparisons pool all mapped land in California.
Method
Shares are by mapped land area: each map unit’s acres in the county times each soil component’s percentage. Open water is excluded. Topsoil values use the first mineral horizon of each component. Full methodology.

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