San Juan Area, Puerto Rico
The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high 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 San Juan Area, Puerto Rico.
| Soil Map Unit | Acres | Drainage | Hydro Group | Dwellings | Septic |
|---|---|---|---|---|---|
| Mucara clay, 40 to 60 percent slopes | 74K | Well drained | D | Very limited | Very limited |
| Caguabo clay loam, 40 to 60 percent slopes | 54K | Well drained | D | Very limited | Very limited |
| Naranjito silty clay loam, 40 to 60 percent slopes | 27K | Well drained | D | Very limited | Very limited |
| Urban land-Vega Alta complex, 2 to 12 percent slopes | 25K | Not rated | Not rated | ||
| Humatas clay, 20 to 40 percent slopes | 22K | Well drained | C | Very limited | Very limited |
| Humatas clay, 40 to 60 percent slopes | 21K | Well drained | C | Very limited | Very limited |
| Maricao clay, 20 to 60 percent slopes | 20K | Well drained | C | Very limited | Very limited |
| Mucara clay, 20 to 40 percent slopes | 18K | Well drained | D | Very limited | Very limited |
| Consumo clay, 40 to 60 percent slopes | 17K | Well drained | B | Very limited | Very limited |
| Urban land | 16K | Not rated | Not rated | ||
| Los Guineos clay, 40 to 60 percent slopes | 13K | Well drained | C | Very limited | Very limited |
| Pandura sandy loam, 40 to 60 percent slopes | 13K | Well drained | D | Very limited | Very limited |
| Tanama-Rock outcrop complex, 20 to 60 percent slopes | 7K | Well drained | D | Very limited | Very limited |
| Daguey clay, 12 to 20 percent slopes | 6K | Well drained | B | Very limited | Very limited |
| Naranjito silty clay loam, 20 to 40 percent slopes | 6K | Well drained | D | Very limited | Very limited |
| Toa silty clay loam, 0 to 2 percent slopes, occasionally flooded | 5K | Well drained | B | Very limited | Very limited |
| Aceitunas clay, 5 to 12 percent slopes | 5K | Well drained | B | Somewhat limited | Somewhat limited |
| Lirios silty clay loam, 20 to 60 percent slopes, eroded | 4K | Well drained | C | Very limited | Very limited |
| Urban land-Mucara complex, 12 to 40 percent slopes | 4K | Well drained | D | Very limited | Very limited |
| Bajura clay, 0 to 2 percent slopes, frequently flooded | 4K | Poorly drained | C/D | Very limited | Very limited |
What This Means
Building & Foundations
About 87% 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 87% 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.