Mahaska County, Iowa
The dominant drainage class is Moderately well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). This report summarizes the major soil map units across the survey area to help you understand what to expect when buying, building, or gardening in Mahaska County, Iowa.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Otley silty clay loam, 2 to 5 percent slopes | 28K | Moderately well drained | C | Very limited | Very limited |
| Ladoga silt loam, 5 to 9 percent slopes, eroded | 19K | Moderately well drained | C | Somewhat limited | Very limited |
| Mahaska silty clay loam, 0 to 2 percent slopes | 19K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Colo-Ely complex, 0 to 5 percent slopes | 18K | Poorly drained | C/D | Very limited | Very limited |
| Taintor silty clay loam, 0 to 2 percent slopes | 16K | Poorly drained | D | Very limited | Very limited |
| Ladoga silt loam, 2 to 5 percent slopes | 14K | Moderately well drained | C | Somewhat limited | Very limited |
| Ladoga silt loam, 9 to 14 percent slopes, eroded | 13K | Moderately well drained | C | Somewhat limited | Very limited |
| Otley silty clay loam, 5 to 9 percent slopes, eroded | 13K | Moderately well drained | C | Very limited | Very limited |
| Clinton silt loam, 9 to 14 percent slopes, eroded | 12K | Moderately well drained | C | Somewhat limited | Very limited |
| Clinton silt loam, 5 to 9 percent slopes, eroded | 11K | Moderately well drained | C | Somewhat limited | Very limited |
| Mahaska silty clay loam, 2 to 5 percent slopes | 10K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Nodaway silt loam, 0 to 2 percent slopes | 8K | Moderately well drained | B | Very limited | Very limited |
| Zook silty clay loam, 0 to 2 percent slopes, occasionally flooded | 8K | Poorly drained | D | Very limited | Very limited |
| Otley silty clay loam, 5 to 9 percent slopes | 7K | Moderately well drained | C | Very limited | Very limited |
| Ladoga silt loam, 5 to 9 percent slopes | 7K | Moderately well drained | C | Somewhat limited | Very limited |
| Nira silty clay loam, 5 to 9 percent slopes, moderately eroded | 6K | Moderately well drained | C | Very limited | Very limited |
| Lindley-Keswick complex, 14 to 18 percent slopes, moderately eroded | 6K | Well drained | C | Very limited | Very limited |
| Colo silty clay loam, 0 to 2 percent slopes, occasionally flooded | 6K | Poorly drained | C/D | Very limited | Very limited |
| Nodaway-Vesser silt loams, 2 to 5 percent slopes | 5K | Moderately well drained | B | Very limited | Very limited |
| Clinton silt loam, 14 to 18 percent slopes, eroded | 5K | Moderately well drained | C | Very limited | Very limited |
What This Means
Building & Foundations
About 66% of soils are rated "very limited" for dwellings with basements. Specific challenges include steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 100% of soils are rated "very limited" for septic absorption fields. Despite good drainage overall, limitations may stem from shallow bedrock, steep slopes, or seasonal conditions. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Well-drained soils on sloped terrain — good for most plants but watch for erosion. Terracing, contour planting, and mulching help retain moisture and topsoil. Drip irrigation is more effective than sprinklers on slopes.