Linn County, Iowa
The most common soil here is Kenyon, on about 10% of the land: a loam, a balanced mix that crumbles in your hand. Fayette and Clyde come next.
About 39% of the land drains well, and 37% stays wet for long stretches; groundwater comes within two feet of the surface under 37% of it.
USDA rates 92% of the land very limited for a standard septic drain field, and 45% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 8% of the land floods occasionally or more, and bedrock lies within 40 inches under 1% of it.
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 Linn 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 Moderately well drained and the dominant hydrologic group is C/D (varies with drainage). 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 Linn 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 |
|---|---|---|---|---|---|
| Kenyon loam, 2 to 5 percent slopes | 27K | Moderately well drained | C | Somewhat limited | Very limited |
| Dinsdale silty clay loam, 2 to 5 percent slopes | 23K | Moderately well drained | C | Somewhat limited | Very limited |
| Clyde silty clay loam, 0 to 3 percent slopes | 22K | Poorly drained | C/D | Very limited | Very limited |
| Klinger silty clay loam, 1 to 4 percent slopes | 17K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Spillville-Sigglekov complex, 0 to 2 percent slopes, frequently flooded | 16K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Clyde-Floyd complex, 1 to 4 percent slopes | 13K | Poorly drained | C/D | Very limited | Very limited |
| Kenyon loam, 5 to 9 percent slopes | 12K | Moderately well drained | C | Somewhat limited | Very limited |
| Floyd loam, 1 to 4 percent slopes | 10K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Ostrander loam, 2 to 5 percent slopes | 10K | Well drained | B | Not limited | Somewhat limited |
| Colo-Ely complex, 0 to 5 percent slopes | 10K | Poorly drained | C/D | Very limited | Very limited |
| Colo silty clay loam, 0 to 2 percent slopes, occasionally flooded | 9K | Poorly drained | C/D | Very limited | Very limited |
| Spillville loam, 0 to 2 percent slopes, occasionally flooded | 9K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Franklin silt loam, 1 to 3 percent slopes | 9K | Somewhat poorly drained | C/D | Very limited | Very limited |
| Kenyon loam, 5 to 9 percent slopes, eroded | 8K | Moderately well drained | C | Somewhat limited | Very limited |
| Dickinson fine sandy loam, loam substratum, 2 to 5 percent slopes | 7K | Well drained | A | Not limited | Somewhat limited |
| Sparta loamy sand, 2 to 5 percent slopes | 6K | Excessively drained | A | Not limited | Very limited |
| Marshan clay loam, 0 to 2 percent slopes, rarely flooded | 6K | Poorly drained | C/D | Very limited | Very limited |
| Tama silty clay loam, 2 to 5 percent slopes | 6K | Well drained | C | Somewhat limited | Very limited |
| Dickinson fine sandy loam, 2 to 5 percent slopes | 6K | Well drained | A | Not limited | Very limited |
| Sparta loamy sand, 5 to 9 percent slopes | 5K | Excessively drained | A | Not 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 45% of soils have significant building limitations, while the rest are generally suitable. Check specific sites carefully — conditions vary across the area.
Septic Systems
About 92% 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.