Polk 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 Polk County, Iowa.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Clarion loam, Bemis moraine, 2 to 6 percent slopes | 46K | Well drained | B | Somewhat limited | Somewhat limited |
| Webster clay loam, Bemis moraine, 0 to 2 percent slopes | 32K | Poorly drained | C/D | Very limited | Very limited |
| Nicollet loam, 1 to 3 percent slopes | 30K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Canisteo clay loam, Bemis moraine, 0 to 2 percent slopes | 26K | Poorly drained | C/D | Very limited | Very limited |
| Urban land | 15K | Not rated | Not rated | ||
| Clarion loam, Bemis moraine, 6 to 10 percent slopes, moderately eroded | 13K | Well drained | B | Somewhat limited | Somewhat limited |
| Water | 12K | Not rated | Not rated | ||
| Coland clay loam, 0 to 2 percent slopes, occasionally flooded | 11K | Poorly drained | C/D | Very limited | Very limited |
| Dockery-Quiver silt loams, 0 to 2 percent slopes, occasionally flooded | 10K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Clarion-Urban land complex, 2 to 5 percent slopes | 10K | Well drained | B | Somewhat limited | Somewhat limited |
| Spillville-Coland complex, channeled, 0 to 2 percent slopes | 9K | Moderately well drained | B | Very limited | Very limited |
| Clarion-Urban land complex, 5 to 9 percent slopes | 7K | Well drained | B | Somewhat limited | Somewhat limited |
| Spillville loam, 0 to 2 percent slopes, occasionally flooded | 6K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Colo-Judson silty clay loams, 0 to 5 percent slopes, occasionally flooded | 6K | Poorly drained | C/D | Very limited | Very limited |
| Lester loam, Bemis moraine, 2 to 6 percent slopes | 6K | Well drained | C | Somewhat limited | Very limited |
| Orthents, loamy | 5K | Not rated | Not rated | ||
| Tama silty clay loam, 5 to 9 percent slopes, eroded | 5K | Well drained | C | Somewhat limited | Very limited |
| Hayden loam, Bemis moraine, 22 to 40 percent slopes | 4K | Well drained | C | Very limited | Very limited |
| Coland, occasionally flooded-Terril complex, 2 to 5 percent slopes | 4K | Poorly drained | C/D | Very limited | Very limited |
| Orthents-urban land complex, 0 to 5 percent slopes | 3K | Not rated | Not rated |
What This Means
Building & Foundations
About 53% 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 57% 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
Drainage is generally favorable for gardening. Adding compost and mulch will improve fertility and water retention. Test your soil's pH before planting — most vegetables prefer 6.0-7.0.