Soil series profile
Cahaba soil series
Cahaba is a well drained soil with a sandy loam surface, mapped on 632,859 acres in 118 counties across 8 states. Hydrologic group B.
- Drainage class
- Well drained >99% of mapped acres
- Hydrologic group
- B 76% of mapped acres
- Typical topsoil pH
- 5.3 strongly acidic · range 5.0–5.3
- Mapped area
- 633k acres in 118 counties, 8 states
Typical Cahaba profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–11 in (H1) | Sandy loam | 5.0 | 9% | 68% | 1.25% |
| 11–38 in (H2) | Sandy clay loam | 5.0 | 26% | 57% | 0.2% |
| 38–80 in (H3) | Sandy loam | 5.0 | 17% | 64% | 0.1% |
What this means
What Cahaba soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Cahaba soils is strongly acidic: pH 5.3 (most land between 5.0 and 5.3). 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 59% of mapped Cahaba acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is fine sandy loam (55% of mapped Cahaba acres).
>99% of mapped Cahaba 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 79% of the acres in mapped Cahaba soils very limited, <1% somewhat limited and <1% not limited (21% not rated, such as urban land, pits or water).
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 32% of the acres (14% occasional, 0% frequent).
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Cahaba soil is found
Mapped acres
Cahaba is mapped in Louisiana, Mississippi, Alabama, Arkansas, Oklahoma, South Carolina, Georgia and Texas. The 60 counties with the most Cahaba acres:
| County | Acres | Share of county land |
|---|---|---|
| Marshall County, MS | 59,681 | 13.7% |
| Ouachita County, AR | 31,993 | 6.9% |
| McCurtain County, OK | 26,751 | 2.3% |
| Jackson Parish, LA | 23,430 | 6.4% |
| Tangipahoa Parish, LA | 16,598 | 3.3% |
| Winn Parish, LA | 16,247 | 2.7% |
| Marengo County, AL | 15,712 | 2.8% |
| Allen Parish, LA | 15,262 | 3.1% |
| Lowndes County, MS | 15,133 | 4.8% |
| Bienville Parish, LA | 13,918 | 2.7% |
| Lee County, MS | 13,427 | 4.8% |
| Perry County, MS | 12,849 | 3.2% |
| Washington Parish, LA | 11,286 | 2.6% |
| Vernon Parish, LA | 10,835 | 1.3% |
| Webster Parish, LA | 10,408 | 2.7% |
| Wayne County, MS | 10,394 | 2.1% |
| St. Tammany Parish, LA | 10,214 | 1.9% |
| Pickens County, AL | 9,927 | 1.9% |
| Lawrence County, MS | 9,721 | 3.7% |
| De Soto Parish, LA | 8,933 | 1.6% |
| Pike County, MS | 8,685 | 3.5% |
| Perry County, AL | 8,379 | 2.1% |
| Greene County, AL | 8,330 | 2.5% |
| Union County, AR | 8,306 | 1.2% |
| Calhoun County, AR | 8,189 | 2.0% |
| Marion County, MS | 8,098 | 2.4% |
| Rapides Parish, LA | 7,850 | 0.9% |
| Florence County, SC | 7,700 | 1.6% |
| Union Parish, LA | 7,631 | 1.4% |
| George County, MS | 7,602 | 2.6% |
| Dallas County, AR | 7,535 | 1.8% |
| Sumter County, AL | 7,297 | 1.5% |
| Natchitoches Parish, LA | 6,829 | 0.8% |
| Hale County, AL | 6,651 | 1.9% |
| Claiborne Parish, LA | 6,624 | 1.4% |
| Monroe County, MS | 6,543 | 1.4% |
| Columbia County, AR | 6,310 | 1.3% |
| Grant Parish, LA | 5,818 | 1.4% |
| Conecuh County, AL | 5,744 | 1.2% |
| Montgomery County, AL | 5,444 | 1.2% |
| Beauregard Parish, LA | 5,300 | 0.7% |
| Wilcox County, AL | 5,247 | 1.1% |
| Jones County, MS | 4,861 | 1.1% |
| Drew County, AR | 4,642 | 0.9% |
| Copiah County, MS | 4,198 | 0.9% |
| LaSalle Parish, LA | 4,184 | 1.0% |
| Bossier Parish, LA | 4,168 | 0.8% |
| Bibb County, AL | 4,088 | 1.2% |
| Greene County, MS | 4,035 | 0.9% |
| Cleveland County, AR | 4,030 | 1.1% |
| Bradley County, AR | 3,799 | 0.9% |
| Ashley County, AR | 3,715 | 0.6% |
| Tuscaloosa County, AL | 3,656 | 0.5% |
| Caldwell Parish, LA | 3,538 | 1.0% |
| Grant County, AR | 3,462 | 0.9% |
| Caddo Parish, LA | 3,304 | 0.6% |
| Monroe County, AL | 3,281 | 0.6% |
| St. Helena Parish, LA | 3,170 | 1.2% |
| Lowndes County, AL | 3,154 | 0.8% |
| Livingston Parish, LA | 3,118 | 0.8% |
Septic absorption fields
NRCS rating, share of Cahaba acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.3% |
| Somewhat limited | 0.1% |
| Very limited | 78.6% |
| Not rated | 21.0% |
Drainage, water table and flooding
Share of Cahaba acres
- Depth to seasonal high water table
- About 2.0 feet (24 in) (median where reported).
- Flooding
- Mapped as flooding on 32% of acres (14% occasional, 0% frequent).
- Slope
- Typically 1–18% (median 2%).
- Topsoil organic matter
- Median 1.2%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 99.9% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
| Not rated | 0.1% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 3.5% |
| B: moderate infiltration | 75.7% |
| 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 | 20.8% |
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 Cahaba (component kind "Series") in SSURGO: 632,859 acres.
- Method
- Shares are by mapped acres of Cahaba components. The profile comes from the single largest Cahaba component. Full methodology.