Decatur County, Iowa
The most common soil here is Gara, on about 10% of the land: a loam, a balanced mix that crumbles in your hand. Lindley and Armstrong come next.
About 23% of the land drains well, and 65% stays wet for long stretches; groundwater comes within two feet of the surface under 65% of it.
USDA rates 98% of the land very limited for a standard septic drain field, and 94% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 11% of the land floods occasionally or more.
Soils change over short distances, so look up an address below for the soil at that exact spot and the reasons behind each rating.
The soils you're most likely standing on
The biggest named soils in Decatur County, Iowa, each drawn five feet deep from its official USDA description, in its recorded colors.
Dots mark gravel; white flecks mark lime. Shares are by acres across the survey area, and each mapped patch usually mixes several of these soils.
The biggest mapped areas
The dominant drainage class is Somewhat poorly drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Alfisols — moderately leached forest soils with a clay-enriched subsoil. 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 Decatur County, Iowa. Search your address to find the exact soil composition, drainage, and series details at your specific location.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Gara clay loam, 14 to 18 percent slopes, moderately eroded | 24K | Well drained | C | Very limited | Very limited |
| Olmitz-Zook-Vesser complex, 0 to 5 percent slopes | 24K | Poorly drained | B | Very limited | Very limited |
| Armstrong clay loam, 9 to 14 percent slopes, moderately eroded | 22K | Somewhat poorly drained | D | Very limited | Very limited |
| Nodaway-Lawson-Klum complex, 0 to 3 percent slopes, occasionally flooded | 18K | Moderately well drained | B | Very limited | Very limited |
| Arispe silty clay loam, 5 to 9 percent slopes, moderately eroded | 15K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Lindley loam, 18 to 40 percent slopes | 13K | Well drained | C | Very limited | Very limited |
| Lindley clay loam, 18 to 25 percent slopes, moderately eroded | 12K | Well drained | C | Very limited | Very limited |
| Grundy silty clay loam, 2 to 5 percent slopes | 11K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Lamoni clay loam, 9 to 14 percent slopes, moderately eroded | 10K | Somewhat poorly drained | D | Very limited | Very limited |
| Clarinda silty clay loam, 5 to 9 percent slopes, moderately eroded | 9K | Poorly drained | D | Very limited | Very limited |
| Cantril-Coppock-Nodaway complex, 2 to 9 percent slopes | 8K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Bucknell clay loam, 9 to 14 percent slopes, moderately eroded | 8K | Somewhat poorly drained | D | Very limited | Very limited |
| Keswick clay loam, 9 to 14 percent slopes, moderately eroded | 7K | Somewhat poorly drained | D | Very limited | Very limited |
| Gara clay loam, 18 to 25 percent slopes, moderately eroded | 6K | Well drained | C | Very limited | Very limited |
| Mystic clay loam, 9 to 14 percent slopes, moderately eroded | 6K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Shelby clay loam, 14 to 18 percent slopes, moderately eroded | 6K | Well drained | C | Very limited | Very limited |
| Haig silty clay loam, 0 to 2 percent slopes | 6K | Poorly drained | D | Very limited | Very limited |
| Keswick loam, 9 to 14 percent slopes | 6K | Somewhat poorly drained | D | Very limited | Very limited |
| Shelby clay loam, 9 to 14 percent slopes, moderately eroded | 5K | Well drained | C | Somewhat limited | Very limited |
| Zook silt loam, heavy till, 0 to 2 percent slopes, occasionally flooded, overwash | 5K | Poorly drained | C/D | Very limited | Very limited |
Soil Orders in This Area
The USDA classifies every soil into one of 12 soil orders. Here are the dominant orders found in this survey area.
What This Means
Building & Foundations
About 94% 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 98% of soils are rated "very limited" for septic absorption fields. Poorly drained soils can't absorb septic effluent effectively. Engineered or alternative systems are frequently required. Always get a professional perc test before purchasing land that needs septic.
Gardening & Agriculture
Many soils hold water for extended periods. Raised beds are highly recommended to improve drainage for vegetables. Well-adapted native plants and water-loving species will do best in natural conditions.