Soil series profile
Ethan soil series
Ethan is a well drained soil with a loam surface, mapped on 742,248 acres in 34 counties across 2 states. Hydrologic group C.
- Drainage class
- Well drained 100% of mapped acres
- Hydrologic group
- C 86% of mapped acres
- Typical topsoil pH
- 7.7 slightly alkaline · range 7.5–7.7
- Mapped area
- 742k acres in 34 counties, 2 states
Typical Ethan profile
Texture and pH by depth
Show as a table
| Depth | Texture | pH | Clay | Sand | Organic matter |
|---|---|---|---|---|---|
| 0–7 in (Ap) | Loam | 7.7 | 22% | 38% | 2.5% |
| 7–33 in (Bk) | Clay loam | 7.9 | 28% | 38% | 0.75% |
| 33–79 in (C) | Clay loam | 7.9 | 28% | 38% | 0.25% |
What this means
What Ethan soil means for gardens, lawns and septic systems
For gardens
Typical topsoil in Ethan soils is slightly alkaline: pH 7.7 (most land between 7.5 and 7.7). Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).
Loamy topsoil (loam, silt loam and similar) covers >99% of mapped Ethan acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is loam (>99% of mapped Ethan acres).
100% of mapped Ethan acres is moderately well to excessively drained, which suits most garden plants.
For lawns and yards
On 86% 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.
For a septic system
For conventional septic absorption fields, NRCS rates 88% of the acres in mapped Ethan soils very limited, 13% 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.
Where Ethan soil is found
Mapped acres
Ethan is mapped in South Dakota and Iowa.
| County | Acres | Share of county land |
|---|---|---|
| Charles Mix County, SD | 74,357 | 10.7% |
| Hand County, SD | 59,093 | 6.4% |
| Jerauld County, SD | 48,398 | 14.3% |
| Bon Homme County, SD | 47,428 | 13.1% |
| Hanson County, SD | 43,662 | 5.5% |
| Hutchinson County, SD | 43,610 | 5.5% |
| Hyde County, SD | 42,306 | 7.7% |
| Yankton County, SD | 33,664 | 10.1% |
| Turner County, SD | 33,542 | 8.5% |
| Douglas County, SD | 31,565 | 11.4% |
| Minnehaha County, SD | 29,488 | 5.7% |
| Aurora County, SD | 28,344 | 6.3% |
| McCook County, SD | 26,369 | 7.2% |
| Sanborn County, SD | 23,772 | 6.5% |
| Beadle County, SD | 21,741 | 2.7% |
| Kingsbury County, SD | 19,977 | 3.8% |
| Lake County, SD | 18,877 | 5.3% |
| Davison County, SD | 16,032 | 6.2% |
| Clay County, SD | 15,236 | 5.7% |
| Brule County, SD | 14,937 | 1.8% |
| Buffalo County, SD | 14,937 | 1.8% |
| Spink County, SD | 13,998 | 1.5% |
| Miner County, SD | 11,156 | 3.2% |
| Moody County, SD | 9,517 | 2.9% |
| Sully County, SD | 7,419 | 1.2% |
| Potter County, SD | 4,583 | 0.8% |
| Hughes County, SD | 3,826 | 0.8% |
| Faulk County, SD | 2,003 | 0.3% |
| Clark County, SD | 1,579 | 0.3% |
| Lincoln County, SD | 298 | 0.1% |
| Brookings County, SD | 286 | 0.1% |
| Union County, SD | 210 | 0.1% |
| Lyon County, IA | 34 | 0.0% |
| Walworth County, SD | 3 | 0.0% |
Septic absorption fields
NRCS rating, share of Ethan acres
Show as a table
| Category | Share of acres |
|---|---|
| Not limited | 0.0% |
| Somewhat limited | 12.5% |
| Very limited | 87.5% |
Drainage, water table and flooding
Share of Ethan 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 4–13% (median 5%).
- Topsoil organic matter
- Median 2.5%.
Drainage class
Show as a table
| Category | Share of acres |
|---|---|
| Excessively drained | 0.0% |
| Somewhat excessively drained | 0.0% |
| Well drained | 100.0% |
| Moderately well drained | 0.0% |
| Somewhat poorly drained | 0.0% |
| Poorly drained | 0.0% |
| Very poorly drained | 0.0% |
Hydrologic soil group
Show as a table
| Category | Share of acres |
|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 0.0% |
| B: moderate infiltration | 13.7% |
| C: slow infiltration | 86.3% |
| 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 Ethan (component kind "Series") in SSURGO: 742,248 acres.
- Method
- Shares are by mapped acres of Ethan components. The profile comes from the single largest Ethan component. Full methodology.