McNairy County, Tennessee
The most common soil here is Smithdale, on about 36% of the land: a fine sandy loam, gritty and crumbly. Luverne and Enville come next.
About 56% of the land drains well, and 19% stays wet for long stretches; groundwater comes within two feet of the surface under 32% of it.
USDA rates 97% of the land very limited for a standard septic drain field, and 72% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 23% of the land floods occasionally or more, and bedrock lies within 40 inches under 3% 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 McNairy County, Tennessee, 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 Well drained and the dominant hydrologic group is B (moderate infiltration). The most common soil order is Ultisols — strongly weathered soils with clay-enriched subsoils, common in warm humid climates. 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 McNairy County, Tennessee. 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 |
|---|---|---|---|---|---|
| Smithdale fine sandy loam, 12 to 25 percent slopes | 51K | Well drained | B | Very limited | Very limited |
| Smithdale loam, 12 to 25 percent slopes, severely eroded | 29K | Well drained | B | Very limited | Very limited |
| Enville fine sandy loam, occasionally flooded | 28K | Somewhat poorly drained | B/D | Very limited | Very limited |
| Luverne fine sandy loam, 12 to 25 percent slopes | 26K | Well drained | C | Very limited | Very limited |
| Bibb fine sandy loam, 0 to 2 percent slopes, frequently flooded | 26K | Poorly drained | B/D | Very limited | Very limited |
| Iuka fine sandy loam, 0 to 2 percent slopes, occasionally flooded | 24K | Moderately well drained | C | Very limited | Very limited |
| Smithdale fine sandy loam, 5 to 8 percent slopes | 22K | Well drained | C | Not limited | Very limited |
| Smithdale loam, 8 to 15 percent slopes, severely eroded | 20K | Well drained | B | Somewhat limited | Very limited |
| Smithdale fine sandy loam, 8 to 15 percent slopes | 15K | Well drained | B | Somewhat limited | Very limited |
| Silerton silt loam, 2 to 5 percent slopes | 11K | Well drained | C | Somewhat limited | Very limited |
| Oktibbeha and Sumter soils, 8 to 20 percent slopes | 11K | Moderately well drained | D | Very limited | Very limited |
| Luverne fine sandy loam, 8 to 12 percent slopes | 8K | Well drained | C | Somewhat limited | Very limited |
| Freeland silt loam, 1 to 4 percent slopes | 7K | Moderately well drained | C | Very limited | Very limited |
| Hatchie silt loam, 0 to 2 percent slopes | 7K | Somewhat poorly drained | D | Very limited | Very limited |
| Dulac silt loam, 2 to 5 percent slopes, severely eroded | 6K | Moderately well drained | D | Very limited | Very limited |
| Udorthents, loamy | 6K | Not rated | Not rated | ||
| Luverne clay loam, 8 to 12 percent slopes, severely eroded | 6K | Well drained | C | Somewhat limited | Very limited |
| Providence silt loam, 2 to 5 percent slopes | 5K | Moderately well drained | C | Very limited | Very limited |
| Paden silt loam, 2 to 5 percent slopes | 5K | Moderately well drained | C/D | Very limited | Very limited |
| Freeland silt loam, 1 to 4 percent slopes, severely eroded | 5K | Moderately well drained | C | 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 72% 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 97% 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.