Soil series profile

Vassar soil series

Vassar is a well drained soil with a ashy silt loam surface, mapped on 79,340 acres in 6 counties across 2 states. Hydrologic group B.

#4218 by mapped area ashy over loamy Typic Udivitrands (Andisols)

Drainage class: Well drained
Hydrologic group: B
Typical topsoil pH: 6.2
Mapped area: 79k

Typical Vassar 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 Vassar horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–1 in (Oi)	Slightly decomposed plant material	5.0	Not reported	Not reported	75%
1–6 in (A)	Ashy silt loam	6.2	8%	35%	5.5%
6–19 in (Bw1)	Ashy silt loam	6.3	8%	35%	2%
19–29 in (2Bw2)	Gravelly sandy loam	5.8	3%	67%	0.45%
29–53 in (2C)	Gravelly sandy loam	5.8	3%	67%	0.25%
53–59 in (2Cr)	Bedrock	Not reported	Not reported	Not reported	Not reported

Representative values from the most extensive Vassar map unit (Vassar ashy silt loam, 30 to 65 percent slopes, survey area ID606). 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 Vassar soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Vassar soils is slightly acidic: pH 6.2 (most land between 6.1 and 6.5), the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Vassar acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is ashy silt loam (78% of mapped Vassar acres).

100% of mapped Vassar acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

47% 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 100% of the acres in mapped Vassar soils very limited, 0% somewhat limited and 0% not 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.

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 Vassar soil is found

Mapped acres

Vassar is mapped in Idaho and Washington.

Counties with the most mapped Vassar soil
County	Acres	Share of county land
Kootenai County, ID	37,977	5.5%
Clearwater County, ID	17,491	1.3%
Pend Oreille County, WA	11,825	1.4%
Stevens County, WA	5,437	0.4%
Latah County, ID	4,230	0.8%
Bonner County, ID	2,380	0.3%

Septic absorption fields

NRCS rating, share of Vassar acres

Not limited 0%

Somewhat limited 0%

Very limited 100%

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

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Septic tank absorption field rating across mapped Vassar acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	100.0%

Drainage, water table and flooding

Share of Vassar 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 20–53% (median 45%).
Topsoil organic matter: Median 5.3%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained 100%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

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

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Drainage class across mapped Vassar acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	100.0%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 47%

B: moderate infiltration 53%

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%

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

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Hydrologic soil group across mapped Vassar acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	47.4%
B: moderate infiltration	52.6%
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%

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 Vassar (component kind "Series") in SSURGO: 79,340 acres.
Method: Shares are by mapped acres of Vassar components. The profile comes from the single largest Vassar component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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