Soil series profile
Dewey soil series
Dewey is a well drained soil with a silty clay loam surface, mapped on 690,069 acres in 59 counties across 4 states. Hydrologic group B.
- Drainage class
- Well drained >99% of mapped acres
- Hydrologic group
- B >99% of mapped acres
- Typical topsoil pH
- 5.3 strongly acidic · range 5.0–5.5
- Mapped area
- 690k acres in 59 counties, 4 states
Typical Dewey profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–4 in (A) | Silty clay loam | 5.5 | 35% | 10% | 1.5% |
| 4–12 in (BA) | Silty clay loam | 5.0 | 39% | 18% | 0.25% |
| 12–60 in (Bt) | Clay | 5.0 | 43% | 28% | 0.2% |
What this means
What Dewey soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Dewey soils is strongly acidic: pH 5.3 (most land between 5.0 and 5.5). 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 97% of mapped Dewey acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (48% of mapped Dewey acres).
>99% of mapped Dewey 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 36% of the acres in mapped Dewey soils very limited, 64% somewhat limited and 0% not limited.
Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.
Where Dewey soil is found
Mapped acres
Dewey is mapped in Tennessee, Alabama, Kentucky and Georgia.
| County | Acres | Share of county land |
|---|---|---|
| Washington County, TN | 57,806 | 27.7% |
| Clinton County, KY | 45,169 | 36.0% |
| Jefferson County, TN | 41,942 | 23.7% |
| Greene County, TN | 41,379 | 11.3% |
| Knox County, TN | 40,061 | 12.3% |
| Loudon County, TN | 38,648 | 26.3% |
| Lauderdale County, AL | 37,853 | 10.0% |
| Blount County, TN | 35,634 | 10.1% |
| Talladega County, AL | 28,514 | 6.9% |
| Grainger County, TN | 25,940 | 14.3% |
| Monroe County, TN | 24,264 | 6.0% |
| Hawkins County, TN | 21,504 | 6.9% |
| Cocke County, TN | 21,384 | 7.8% |
| Limestone County, AL | 20,975 | 6.6% |
| Hamblen County, TN | 20,589 | 19.9% |
| Sevier County, TN | 16,284 | 4.4% |
| McMinn County, TN | 15,476 | 5.6% |
| Roane County, TN | 15,240 | 6.6% |
| St. Clair County, AL | 14,802 | 4.3% |
| Franklin County, TN | 10,336 | 3.0% |
| Cherokee County, AL | 8,538 | 2.8% |
| Robertson County, TN | 8,508 | 2.8% |
| Hamilton County, TN | 6,931 | 2.0% |
| Anderson County, TN | 6,897 | 3.2% |
| Madison County, AL | 6,873 | 1.6% |
| Meigs County, TN | 5,879 | 4.7% |
| Calhoun County, AL | 5,874 | 1.7% |
| Etowah County, AL | 5,857 | 2.0% |
| Coffee County, TN | 5,436 | 2.0% |
| Walker County, GA | 5,369 | 1.9% |
| Gordon County, GA | 4,967 | 2.7% |
| Shelby County, AL | 4,142 | 1.0% |
| Jackson County, AL | 3,938 | 0.7% |
| Polk County, GA | 3,682 | 1.9% |
| Morgan County, AL | 3,610 | 1.1% |
| Marion County, TN | 3,229 | 1.0% |
| Claiborne County, TN | 2,780 | 1.0% |
| Floyd County, GA | 2,598 | 0.8% |
| Bradley County, TN | 2,597 | 1.3% |
| Lincoln County, TN | 2,136 | 0.6% |
| Rhea County, TN | 1,905 | 0.9% |
| Union County, TN | 1,735 | 1.2% |
| DeKalb County, AL | 1,700 | 0.4% |
| Chattooga County, GA | 1,619 | 0.8% |
| Metcalfe County, KY | 1,599 | 0.9% |
| Murray County, GA | 1,197 | 0.6% |
| Campbell County, TN | 1,014 | 0.3% |
| Dade County, GA | 844 | 0.8% |
| Macon County, TN | 843 | 0.4% |
| Putnam County, TN | 761 | 0.3% |
| Whitfield County, GA | 712 | 0.4% |
| Hancock County, TN | 677 | 0.5% |
| Lawrence County, AL | 560 | 0.1% |
| Catoosa County, GA | 430 | 0.4% |
| Clay County, TN | 352 | 0.2% |
| Overton County, TN | 214 | 0.1% |
| Unicoi County, TN | 186 | 0.2% |
| Bledsoe County, TN | 74 | 0.0% |
| White County, TN | 5 | 0.0% |
Septic absorption fields
NRCS rating, share of Dewey acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 63.9% |
| Very limited | 35.6% |
| Not rated | 0.6% |
Drainage, water table and flooding
Share of Dewey 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 4–20% (median 10%).
- Topsoil organic matter
- Median 1.5%.
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) | 0.0% |
| B: moderate infiltration | 99.3% |
| C: slow infiltration | 0.2% |
| 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 | 0.6% |
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 Dewey (component kind "Series") in SSURGO: 690,069 acres.
- Method
- Shares are by mapped acres of Dewey components. The profile comes from the single largest Dewey component. Full methodology.