Allamakee County, Iowa
The dominant drainage class is 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 Allamakee County, Iowa.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Lacrescent silt loam, 25 to 70 percent slopes | 52K | Well drained | C | Very limited | Very limited |
| Fayette silt loam, 9 to 14 percent slopes, moderately eroded | 42K | Well drained | C | Somewhat limited | Very limited |
| Fayette silt loam, 5 to 9 percent slopes, moderately eroded | 37K | Well drained | C | Somewhat limited | Very limited |
| Downs silt loam, 5 to 9 percent slopes, moderately eroded | 30K | Well drained | C | Somewhat limited | Very limited |
| Paintcreek silt loam, 18 to 30 percent slopes | 20K | Well drained | D | Very limited | Very limited |
| Water | 17K | Not rated | Not rated | ||
| Downs silt loam, 2 to 6 percent slopes | 14K | Well drained | C | Somewhat limited | Very limited |
| Caneek silt loam, channeled, 0 to 2 percent slopes | 13K | Poorly drained | B/D | Very limited | Very limited |
| Village silt loam, 9 to 14 percent slopes, moderately eroded | 11K | Well drained | D | Somewhat limited | Very limited |
| Downs silt loam, 9 to 14 percent slopes, moderately eroded | 10K | Well drained | C | Somewhat limited | Very limited |
| Nordness silt loam, 25 to 40 percent slopes | 9K | Well drained | D | Very limited | Very limited |
| Fayette silt loam, 14 to 18 percent slopes, moderately eroded | 7K | Well drained | C | Very limited | Very limited |
| Village silt loam, 14 to 18 percent slopes | 7K | Well drained | D | Very limited | Very limited |
| Ion silt loam, 0 to 2 percent slopes | 7K | Moderately well drained | B | Very limited | Very limited |
| Village silt loam, 14 to 18 percent slopes, moderately eroded | 6K | Well drained | D | Very limited | Very limited |
| Paintcreek silt loam, 14 to 18 percent slopes | 6K | Well drained | D | Very limited | Very limited |
| Dubuque silt loam, 9 to 14 percent slopes, moderately eroded | 6K | Well drained | C | Very limited | Very limited |
| Eitzen silt loam, 0 to 2 percent slopes | 5K | Moderately well drained | B | Very limited | Very limited |
| Eitzen silt loam, 2 to 5 percent slopes | 5K | Moderately well drained | B | Very limited | Very limited |
| Nordness silt loam, 18 to 25 percent slopes | 5K | Well drained | D | Very limited | Very limited |
What This Means
Building & Foundations
About 47% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 94% 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.