County soil summary
Soil types in Calhoun County, Michigan
The most widespread soils are Oshtemo, Kalamazoo and Hillsdale; the most common drainage class is well drained (59% of the land), and typical topsoil pH is 6.0.
- Well or moderately well drained
- 66% of land · state 53%
- Typical topsoil pH
- 6.0 moderately acidic · state 6.0
- Septic fields very limited
- 95% of land · state 95%
- Subject to flooding
- <1% of land, any frequency · state 2%
Most common soils in Calhoun County
Share of mapped land
A county is a patchwork of many soils. These 8 cover 69% of the mapped land; 48 named soil series are mapped here in all.
| Soil | Share of land | Drainage | Topsoil pH |
|---|---|---|---|
| Oshtemo | 17.7% | Well drained | 6.0 |
| Kalamazoo | 14.1% | Well drained | 5.8 |
| Hillsdale | 10.3% | Well drained | 6.5 |
| Houghton | 8.0% | Very poorly drained | Not reported |
| Spinks | 6.6% | Well drained | 6.0 |
| Sebewa | 5.2% | Poorly drained | 6.7 |
| Boyer | 4.6% | Well drained | 6.5 |
| Coloma | 2.6% | Somewhat excessively drained | 5.7 |
What this means
What the soils in Calhoun County mean for gardens, lawns and septic systems
For your garden
Typical topsoil in Calhoun County is moderately acidic: pH 6.0 (most land between 5.8 and 6.5). Many vegetables grow well here, and some gardens benefit from a little lime. Test before adding any.
Loamy topsoil (loam, silt loam and similar) covers 54% of the land: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is sandy loam (39% of the land).
66% of the land is moderately well to excessively drained, which suits most garden plants.
For your lawn and yard
32% of the land is in hydrologic group A, where water soaks in fast. Lawns there dry out quickly; deeper, less frequent watering and organic matter help.
A seasonal high water table comes within 18 inches of the surface on 28% of the land, 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 95% of the land in Calhoun County very limited, 3% somewhat limited and 2% not limited.
That is close to the state as a whole (95% very 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.
Drainage
How long the soil stays wet
The most common drainage class is well drained (59%). 66% of the land is moderately well drained or better, compared with 53% across Michigan.
Show as a table
| Category | Calhoun County | Michigan |
|---|---|---|
| Excessively drained | 1.3% | 9.2% |
| Somewhat excessively drained | 2.1% | 8.5% |
| Well drained | 59.1% | 24.7% |
| Moderately well drained | 3.1% | 10.7% |
| Somewhat poorly drained | 8.8% | 18.0% |
| Poorly drained | 10.4% | 13.2% |
| Very poorly drained | 12.8% | 14.1% |
| Not rated | 2.4% | 1.7% |
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 | Calhoun County | Michigan |
|---|---|---|
| Not limited | 1.6% | 0.4% |
| Somewhat limited | 2.5% | 3.7% |
| Very limited | 95.3% | 94.7% |
| Not rated | 0.6% | 1.2% |
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 | Calhoun County | Michigan |
|---|---|---|
| A: fast infiltration (mostly sandy or gravelly) | 32.3% | 29.1% |
| B: moderate infiltration | 17.8% | 8.5% |
| C: slow infiltration | 17.2% | 8.0% |
| D: very slow infiltration (clayey, shallow or wet) | 2.6% | 8.7% |
| A/D: D as is, A if drained | 13.5% | 17.8% |
| B/D: D as is, B if drained | 12.2% | 10.0% |
| C/D: D as is, C if drained | 2.4% | 16.2% |
| Not rated | 2.0% | 1.6% |
Flooding
Show as a table
| Category | Calhoun County | Michigan |
|---|---|---|
| No flooding | 97.6% | 96.1% |
| Rare or very rare | 0.0% | 0.2% |
| Occasional | 0.2% | 0.4% |
| Frequent or very frequent | 0.7% | 1.8% |
| Not reported | 1.5% | 1.5% |
Seasonal high water table
Show as a table
| Category | Calhoun County | Michigan |
|---|---|---|
| Within 18 inches at some time of year | 28.2% | 49.2% |
| 18 inches to 3.3 feet | 6.7% | 6.2% |
| Deeper than 3.3 feet or none reported | 63.8% | 44.1% |
| Not reported | 1.3% | 0.5% |
Topsoil pH and texture
First mineral layer of each soil
Typical topsoil pH is 6.0 (moderately acidic); 80% of rated land falls between 5.8 and 6.5. Median topsoil organic matter is 1.5%.
Show as a table
| Category | Calhoun County | Michigan |
|---|---|---|
| Strongly acidic (below 5.5) | 0.1% | 29.3% |
| Moderately to slightly acidic (5.5–6.4) | 60.0% | 33.6% |
| Near neutral (6.5–7.3) | 24.3% | 23.0% |
| Alkaline (7.4 and up) | 0.1% | 4.2% |
| Not reported | 15.5% | 9.9% |
Texture
Show as a table
| Category | Calhoun County | Michigan |
|---|---|---|
| Sandy | 30.0% | 42.8% |
| Loamy (loam, silt loam and similar) | 54.3% | 40.2% |
| Clayey (40%+ clay) | 0.0% | 0.4% |
| Organic (muck or peat) | 12.4% | 14.3% |
| Not reported (rock, urban land, etc.) | 3.3% | 2.2% |
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
- Calhoun County, Michigan (FIPS 26025): 451,904 acres of mapped land, 7,872 acres of open water excluded. State comparisons pool all mapped land in Michigan.
- 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.