Island of Molokai, Hawaii
The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). 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 Island of Molokai, Hawaii.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Rough mountainous land | 34K | Well drained | B | Very limited | Very limited |
| Very stony land, eroded | 16K | Well drained | C | Very limited | Very limited |
| Rough broken land | 9K | Well drained | C | Not rated | Not rated |
| Very stony land | 9K | Well drained | D | Very limited | Very limited |
| Rock land | 9K | Well drained | D | Very limited | Very limited |
| Rock outcrop | 7K | C | Very limited | Very limited | |
| Molokai silty clay loam, 3 to 7 percent slopes, MLRA 158 | 7K | Well drained | C | Not limited | Very limited |
| Tropaquods | 4K | Poorly drained | D | Very limited | Very limited |
| Hoolehua silty clay, 7 to 15 percent slopes | 4K | Well drained | C | Somewhat limited | Very limited |
| Molokai silty clay loam, 7 to 15 percent slopes, MLRA 158 | 3K | Well drained | C | Somewhat limited | Very limited |
| Holomua silt loam, 3 to 7 percent slopes | 2K | Well drained | C | Not limited | Very limited |
| Oli medial silt loam, 10 to 30 percent slopes, MLRA 165 | 2K | Well drained | B | Very limited | Very limited |
| Colluvial land | 2K | Well drained | B | Very limited | Very limited |
| Gullied land | 2K | Well drained | Very limited | Very limited | |
| Water | 2K | D | Not rated | Not rated | |
| Lahaina silty clay, 3 to 7 percent slopes, MLRA 158 | 2K | Well drained | B | Not limited | Somewhat limited |
| Mala silty clay, 0 to 3 percent slopes, MLRA 166 | 2K | Well drained | B | Very limited | Very limited |
| Molokai silty clay loam, 0 to 3 percent slopes, MLRA 158 | 2K | Well drained | C | Not limited | Very limited |
| Hoolehua silty clay, 3 to 7 percent slopes | 2K | Well drained | C | Not limited | Very limited |
| Kahanui gravelly silty clay, 3 to 20 percent slopes | 2K | Well drained | C | Somewhat limited | Very limited |
What This Means
Building & Foundations
About 71% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes, poor drainage in some areas, flood-prone areas. A geotechnical assessment is recommended before building.
Septic Systems
About 89% 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.