Soil series profile

Ritzville soil series

Ritzville is a well drained soil with a silt loam surface, mapped on 1,415,900 acres in 16 counties across 2 states. Hydrologic group B.

#89 by mapped area coarse-silty Calcidic Haploxerolls (Mollisols)

Drainage class: Well drained
Hydrologic group: B
Typical topsoil pH: 7.2
Mapped area: 1.4M

Typical Ritzville 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 Ritzville horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–6 in (H1)	Silt loam	7.5	8%	22%	1.5%
6–36 in (H2)	Silt loam	7.5	8%	22%	0.75%
36–60 in (H3)	Silt loam	8.2	8%	22%	0.25%

Representative values from the most extensive Ritzville map unit (Ritzville silt loam, 0 to 5 percent slopes, survey area WA605). 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 Ritzville soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Ritzville soils is neutral: pH 7.2 (most land between 7.2 and 7.5), the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers >99% of mapped Ritzville acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (93% of mapped Ritzville acres).

>99% of mapped Ritzville 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 38% of the acres in mapped Ritzville soils very limited, 61% somewhat limited and 0% not limited.

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 Ritzville soil is found

Mapped acres

Ritzville is mapped in Washington and Oregon.

Counties with the most mapped Ritzville soil
County	Acres	Share of county land
Adams County, WA	311,582	25.5%
Walla Walla County, WA	272,023	33.0%
Benton County, WA	207,499	18.8%
Franklin County, WA	138,161	18.6%
Morrow County, OR	111,548	10.2%
Gilliam County, OR	89,764	11.6%
Yakima County, WA	81,710	4.2%
Umatilla County, OR	79,633	4.7%
Lincoln County, WA	70,640	5.0%
Grant County, WA	18,487	1.1%
Whitman County, WA	9,816	0.7%
Klickitat County, WA	7,506	0.7%
Columbia County, WA	6,089	1.4%
Sherman County, OR	4,867	1.1%
Douglas County, WA	4,030	0.3%
Chelan County, WA	2,546	0.1%

Septic absorption fields

NRCS rating, share of Ritzville acres

Not limited 0%

Somewhat limited 61%

Very limited 38%

Not rated <1%

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

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Septic tank absorption field rating across mapped Ritzville acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	61.4%
Very limited	38.3%
Not rated	0.2%

Drainage, water table and flooding

Share of Ritzville 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 3–23% (median 8%).
Topsoil organic matter: Median 1.5%.

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 <1%

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

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Drainage class across mapped Ritzville acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	99.8%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	0.2%

Hydrologic soil group

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

B: moderate infiltration >99%

C: slow infiltration 0%

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 <1%

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

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Hydrologic soil group across mapped Ritzville acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	99.7%
C: slow infiltration	0.0%
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	0.2%

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 Ritzville (component kind "Series") in SSURGO: 1,415,900 acres.
Method: Shares are by mapped acres of Ritzville components. The profile comes from the single largest Ritzville component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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