Soil series profile

Wadmalaw soil series

Wadmalaw is a poorly drained soil with a fine sandy loam surface, mapped on 38,656 acres in 1 county in SC. Hydrologic group A/D.

#7096 by mapped area fine-loamy Umbric Endoaqualfs (Alfisols)

Drainage class
Poorly drained
100% of mapped acres
Hydrologic group
A/D
100% of mapped acres
Typical topsoil pH
4.7
very strongly acidic · range 4.7–4.7
Mapped area
39k
acres in 1 county, 1 state

Typical Wadmalaw profile

Texture and pH by depth

Typical Wadmalaw soil profile by depth 0 in 20 in 40 in 60 in 80 in 0–9 in · A · pH 4.7 · 10% clay Fine sandy loam 9–13 in · Eg · pH 4.7 · 10% clay Sandy loam 13–51 in · Btg · pH 4.7 · 27% clay Sandy clay loam 51–83 in · BCg · pH 4.7 · 22% clay Sandy clay loam
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 Wadmalaw horizons (representative values)
Depth Texture pH Clay Sand Organic matter
0–9 in (A) Fine sandy loam 4.7 10% 64% 1.5%
9–13 in (Eg) Sandy loam 4.7 10% 67% 0.25%
13–51 in (Btg) Sandy clay loam 4.7 27% 55% 0.25%
51–83 in (BCg) Sandy clay loam 4.7 22% 60% 0.25%

Representative values from the most extensive Wadmalaw map unit (Wadmalaw fine sandy loam, survey area SC690). Other map units of this series vary within the series range.

Hands holding dark garden soil
Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Wadmalaw soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Wadmalaw soils is very strongly acidic: pH 4.7. 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 Wadmalaw acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is fine sandy loam (100% of mapped Wadmalaw acres).

100% of mapped Wadmalaw acres is somewhat poorly to very poorly drained, so soil stays soggy for long spells after rain and in wet seasons. Raised beds, plants that tolerate wet feet, and not working the soil while wet all help.

For lawns and yards

On 100% of mapped acres, 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.

A seasonal high water table comes within 18 inches of the surface on 100% of mapped acres, often in spring. Basements, sump pumps and lawns in low spots feel it first.

For a septic system

For conventional septic absorption fields, NRCS rates 100% of the acres in mapped Wadmalaw 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 Wadmalaw soil is found

Mapped acres

Wadmalaw is mapped in South Carolina.

Counties with the most mapped Wadmalaw soil
County Acres Share of county land
Charleston County, SC 38,656 6.5%

Septic absorption fields

NRCS rating, share of Wadmalaw acres

Not limited 0%
Somewhat limited 0%
Very limited 100%
Septic tank absorption field rating across mapped Wadmalaw acres. Scale 0 to 100% of mapped land.
Show as a table
Septic tank absorption field rating across mapped Wadmalaw acres.
CategoryShare of acres
Not limited0.0%
Somewhat limited0.0%
Very limited100.0%

Drainage, water table and flooding

Share of Wadmalaw acres

Depth to seasonal high water table
About 0 inches (median where reported); within 18 inches on 100% of acres.
Flooding
Not mapped as flooding on most acres.
Slope
Typically 1–1% (median 1%).
Topsoil organic matter
Median 1.5%.

Drainage class

Excessively drained 0%
Somewhat excessively drained 0%
Well drained 0%
Moderately well drained 0%
Somewhat poorly drained 0%
Poorly drained 100%
Very poorly drained 0%
Drainage class across mapped Wadmalaw acres. Scale 0 to 100% of mapped land.
Show as a table
Drainage class across mapped Wadmalaw acres.
CategoryShare of acres
Excessively drained0.0%
Somewhat excessively drained0.0%
Well drained0.0%
Moderately well drained0.0%
Somewhat poorly drained0.0%
Poorly drained100.0%
Very poorly drained0.0%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%
B: moderate infiltration 0%
C: slow infiltration 0%
D: very slow infiltration (clayey, shallow or wet) 0%
A/D: D as is, A if drained 100%
B/D: D as is, B if drained 0%
C/D: D as is, C if drained 0%
Hydrologic soil group across mapped Wadmalaw acres. Scale 0 to 100% of mapped land.
Show as a table
Hydrologic soil group across mapped Wadmalaw acres.
CategoryShare of acres
A: fast infiltration (mostly sandy or gravelly)0.0%
B: moderate infiltration0.0%
C: slow infiltration0.0%
D: very slow infiltration (clayey, shallow or wet)0.0%
A/D: D as is, A if drained100.0%
B/D: D as is, B if drained0.0%
C/D: D as is, C if drained0.0%

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 Wadmalaw (component kind "Series") in SSURGO: 38,656 acres.
Method
Shares are by mapped acres of Wadmalaw components. The profile comes from the single largest Wadmalaw component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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