Soil series profile

Manassas soil series

Manassas is a moderately well drained soil with a silt loam surface, mapped on 12,014 acres in 6 counties in VA. Hydrologic group B.

#13161 by mapped area fine-loamy Ultic Hapludalfs (Alfisols)

Drainage class: Moderately well drained
Hydrologic group: B
Typical topsoil pH: 5.0
Mapped area: 12k

Typical Manassas 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).

Show as a table

Typical Manassas horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–10 in (H1)	Silt loam	5.0	19%	27%	3%
10–43 in (H2)	Silt loam	5.0	26%	18%	0.25%
43–49 in (H3)	Channery sandy loam	5.0	19%	63%	0.25%
49–60 in (H4)	Bedrock	Not reported	Not reported	Not reported	Not reported

Representative values from the most extensive Manassas map unit (Manassas silt loam, 2 to 7 percent slopes, survey area VA153). 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 Manassas soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Manassas soils is very strongly acidic: pH 5.0. Most vegetables and lawn grasses do best around 6.0 to 7.0, so lime is often needed; blueberries, azaleas and rhododendrons like it as it is.

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

100% of mapped Manassas 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 100% of the acres in mapped Manassas 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.

Flooding is mapped on 62% of the acres (5% occasional, 0% 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 Manassas soil is found

Mapped acres

Manassas is mapped in Virginia.

Counties with the most mapped Manassas soil
County	Acres	Share of county land
Prince William County, VA	6,872	3.7%
Loudoun County, VA	2,946	1.0%
Fairfax County, VA	709	0.3%
Orange County, VA	626	0.3%
Albemarle County, VA	584	0.2%
Madison County, VA	276	0.2%

Septic absorption fields

NRCS rating, share of Manassas acres

Not limited 0%

Somewhat limited 0%

Very limited 100%

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

Show as a table

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

Drainage, water table and flooding

Share of Manassas acres

Depth to seasonal high water table: About 2.5 feet (30 in) (median where reported).
Flooding: Mapped as flooding on 62% of acres (5% occasional, 0% frequent).
Slope: Typically 3–5% (median 5%).
Topsoil organic matter: Median 3%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained 0%

Moderately well drained 100%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

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

Show as a table

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

Hydrologic soil group

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

B: moderate infiltration 100%

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

Show as a table

Hydrologic soil group across mapped Manassas acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	100.0%
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 Manassas (component kind "Series") in SSURGO: 12,014 acres.
Method: Shares are by mapped acres of Manassas components. The profile comes from the single largest Manassas component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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