St. Helena Parish, Louisiana
The most common soil here is Tangi, on about 29% of the land: a silt loam, smooth, like flour. Ruston and Ouachita come next.
About 47% of the land drains well, and 13% stays wet for long stretches; groundwater comes within two feet of the surface under 72% of it.
USDA rates 76% of the land very limited for a standard septic drain field, and 75% very limited for homes with basements. That means extra cost or special design, not that it can't be done.
Worth knowing: 27% 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 St. Helena Parish, Louisiana, 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 St. Helena Parish, Louisiana. 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 |
|---|---|---|---|---|---|
| Ouachita, Ochlockonee and Guyton soils, 0 to 3 percent slopes, frequently flooded | 58K | Well drained | B | Very limited | Very limited |
| Ruston-Smithdale association, 3 to 12 percent slopes | 48K | Well drained | B | Not limited | Somewhat limited |
| Tangi silt loam, 1 to 3 percent slopes | 40K | Moderately well drained | C/D | Very limited | Very limited |
| Tangi silt loam, 3 to 8 percent slopes | 39K | Moderately well drained | C/D | Very limited | Very limited |
| Toula silt loam, 1 to 3 percent slopes | 22K | Moderately well drained | D | Very limited | Very limited |
| Fluker silt loam, 0 to 2 percent slopes | 8K | Somewhat poorly drained | D | Very limited | Very limited |
| Ruston fine sandy loam, 1 to 3 percent slopes | 8K | Well drained | B | Not limited | Somewhat limited |
| Bude silt loam, 0 to 2 percent slopes | 6K | Somewhat poorly drained | D | Very limited | Very limited |
| Gilbert silt loam, occasionally flooded | 5K | Poorly drained | D | Very limited | Very limited |
| Satsuma silt loam, 1 to 3 percent slopes | 4K | Somewhat poorly drained | D | Very limited | Very limited |
| Myatt fine sandy loam, occasionally flooded | 3K | Poorly drained | B/D | Very limited | Very limited |
| Lytle silt loam, 3 to 8 percent slopes | 2K | Well drained | B | Not limited | Somewhat limited |
| Myatt fine sandy loam | 2K | Poorly drained | B/D | Very limited | Very limited |
| Smithdale fine sandy loam, 12 to 20 percent slopes | 2K | Well drained | B | Very limited | Very limited |
| Kenefick fine sandy loam, 1 to 3 percent slopes | 2K | Well drained | B | Not limited | Very limited |
| Water | 2K | Not rated | Not rated | ||
| Pits-Arents complex, 0 to 5 percent slopes | 2K | Not rated | Not rated | ||
| Calhoun silt loam, 0 to 1 percent slopes | 1K | Poorly drained | C/D | Very limited | Very limited |
| Lytle silt loam, 1 to 3 percent slopes | 1K | Well drained | B | Not limited | Somewhat limited |
| Dexter very fine sandy loam, 1 to 5 percent slopes | 1K | Well drained | B | 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 75% of soils are rated "very limited" for dwellings with basements. Specific challenges include poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 76% 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.