Mills County, Iowa
The dominant drainage class is Well drained and the dominant hydrologic group is B (moderate infiltration). 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 Mills County, Iowa.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Marshall silty clay loam, 2 to 5 percent slopes | 25K | Well drained | C | Somewhat limited | Very limited |
| Napier silt loam, 2 to 5 percent slopes | 23K | Well drained | B | Not limited | Somewhat limited |
| Monona silt loam, 9 to 14 percent slopes, eroded | 18K | Well drained | B | Somewhat limited | Somewhat limited |
| Exira silty clay loam, 9 to 14 percent slopes, eroded | 17K | Well drained | C | Somewhat limited | Very limited |
| Judson silty clay loam, deep loess, 2 to 5 percent slopes | 15K | Well drained | C | Somewhat limited | Very limited |
| Monona silt loam, 5 to 9 percent slopes, eroded | 11K | Well drained | B | Not limited | Somewhat limited |
| Ida silt loam, 14 to 20 percent slopes, severely eroded | 8K | Well drained | B | Very limited | Very limited |
| Dockery-Quiver silt loams, deep loess, 0 to 2 percent slopes, occasionally flooded | 8K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Marshall silty clay loam, 5 to 9 percent slopes, eroded | 7K | Well drained | C | Somewhat limited | Very limited |
| Kennebec silt loam, 0 to 2 percent slopes, occasionally flooded | 7K | Moderately well drained | B | Very limited | Very limited |
| Marshall silty clay loam, 9 to 14 percent slopes, eroded | 6K | Well drained | C | Somewhat limited | Very limited |
| Colo-Judson silty clay loams, 0 to 5 percent slopes, occasionally flooded | 5K | Poorly drained | C/D | Very limited | Very limited |
| Colo silty clay loam, deep loess, 0 to 2 percent slopes, occasionally flooded | 5K | Poorly drained | C/D | Very limited | Very limited |
| Ida silt loam, 9 to 14 percent slopes, severely eroded | 4K | Well drained | B | Somewhat limited | Somewhat limited |
| Marshall silty clay loam, 5 to 9 percent slopes | 4K | Well drained | C | Somewhat limited | Very limited |
| Zook silty clay loam, 0 to 2 percent slopes, occasionally flooded | 4K | Poorly drained | D | Very limited | Very limited |
| Haynie silt loam, 0 to 2 percent slopes, occasionally flooded | 4K | Moderately well drained | B | Very limited | Very limited |
| Albaton silty clay, 0 to 2 percent slopes, occasionally flooded | 4K | Poorly drained | D | Very limited | Very limited |
| Napier-Gullied land complex, 2 to 10 percent slopes | 4K | Well drained | B | Not limited | Somewhat limited |
| Onawa silty clay, 0 to 2 percent slopes | 4K | Somewhat poorly drained | D | Very limited | Very limited |
What This Means
Building & Foundations
About 27% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 67% 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.