County soil summary
Soil types in Alexandria city, Virginia
The most widespread soils are Kingstowne, Grist Mill and Sassafras; the most common drainage class is well drained (41% of the land), and typical topsoil pH is 4.8.
- Well or moderately well drained
- 50% of land · state 85%
- Typical topsoil pH
- 4.8 very strongly acidic · state 5.3
- Septic fields very limited
- 52% of land · state 77%
- Subject to flooding
- 2% of land, any frequency · state 10%
Most common soils in Alexandria city
Share of mapped land
A county is a patchwork of many soils. These 8 cover 97% of the mapped land; 14 named soil series are mapped here in all.
| Soil | Share of land | Drainage | Topsoil pH |
|---|---|---|---|
| Urban LandLand type, not a soil series | 35.6% | — | — |
| Kingstowne | 17.2% | Well drained | 4.8 |
| Grist Mill | 16.5% | Well drained | 4.8 |
| Urban landLand type, not a soil series | 11.8% | — | — |
| Sassafras | 6.0% | Well drained | 6.0 |
| Woodstown | 3.9% | Moderately well drained | 5.7 |
| Neabsco | 2.9% | Moderately well drained | 5.0 |
| Marumsco | 2.7% | Moderately well drained | 4.3 |
What this means
What the soils in Alexandria city mean for gardens, lawns and septic systems
For your garden
Typical topsoil in Alexandria city is very strongly acidic: pH 4.8 (most land between 4.6 and 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 47% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is sandy loam (26% of the land).
For your lawn and yard
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 52% of the land in Alexandria city very limited, <1% somewhat limited and 0% not limited (47% not rated, such as urban land, pits or water).
Statewide, 77% of the land is very limited, so Alexandria city is less restrictive than typical.
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.
Drainage
How long the soil stays wet
The most common drainage class is well drained (41%). 50% of the land is moderately well drained or better, compared with 85% across Virginia.
Show as a table
| Category | Alexandria city | Virginia |
|---|---|---|
| Excessively drained | 0.0% | 2.1% |
| Somewhat excessively drained | 0.0% | 4.9% |
| Well drained | 40.7% | 67.8% |
| Moderately well drained | 9.5% | 10.1% |
| Somewhat poorly drained | 1.5% | 3.1% |
| Poorly drained | 0.9% | 7.0% |
| Very poorly drained | 0.0% | 2.0% |
| Not rated | 47.4% | 3.0% |
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.
Show as a table
| Category | Alexandria city | Virginia |
|---|---|---|
| Not limited | 0.0% | 0.1% |
| Somewhat limited | 0.2% | 20.6% |
| Very limited | 52.4% | 76.5% |
| Not rated | 47.4% | 2.8% |
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.
Show as a table
| Category | Alexandria city | Virginia |
|---|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% | 10.8% |
| B: moderate infiltration | 10.6% | 49.0% |
| C: slow infiltration | 33.9% | 15.0% |
| D: very slow infiltration (clayey, shallow or wet) | 2.9% | 10.1% |
| A/D: D as is, A if drained | 0.0% | 0.9% |
| B/D: D as is, B if drained | 2.4% | 6.7% |
| C/D: D as is, C if drained | 2.7% | 4.0% |
| Not rated | 47.4% | 3.5% |
Flooding
Show as a table
| Category | Alexandria city | Virginia |
|---|---|---|
| No flooding | 50.3% | 88.5% |
| Rare or very rare | 0.0% | 1.7% |
| Occasional | 2.3% | 2.1% |
| Frequent or very frequent | 0.0% | 6.5% |
| Not reported | 47.4% | 1.2% |
Seasonal high water table
Show as a table
| Category | Alexandria city | Virginia |
|---|---|---|
| Within 18 inches at some time of year | 5.1% | 13.0% |
| 18 inches to 3.3 feet | 6.8% | 9.8% |
| Deeper than 3.3 feet or none reported | 40.7% | 76.1% |
| Not reported | 47.4% | 1.1% |
Topsoil pH and texture
First mineral layer of each soil
Typical topsoil pH is 4.8 (very strongly acidic); 80% of rated land falls between 4.6 and 5.0. Median topsoil organic matter is 0.5%.
Show as a table
| Category | Alexandria city | Virginia |
|---|---|---|
| Strongly acidic (below 5.5) | 51.4% | 64.8% |
| Moderately to slightly acidic (5.5–6.4) | 0.9% | 28.5% |
| Near neutral (6.5–7.3) | 0.0% | 3.4% |
| Alkaline (7.4 and up) | 0.3% | 0.4% |
| Not reported | 47.4% | 3.0% |
Texture
Show as a table
| Category | Alexandria city | Virginia |
|---|---|---|
| Sandy | 6.0% | 9.4% |
| Loamy (loam, silt loam and similar) | 46.6% | 86.6% |
| Clayey (40%+ clay) | 0.0% | 0.2% |
| Organic (muck or peat) | 0.0% | 0.8% |
| Not reported (rock, urban land, etc.) | 47.4% | 2.9% |
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
- Alexandria city, Virginia (FIPS 51510): 8,919 acres of mapped land, 239 acres of open water excluded. State comparisons pool all mapped land in Virginia.
- 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.