Puerto Rico Soil Surveys
Puerto Rico has 7 USDA soil survey areas covering a wide range of landscapes and soil conditions. The most common soil order is Inceptisols — young soils with minimal horizon development but more than Entisols, making up roughly 21% of surveyed soils. Ultisols — strongly weathered soils with clay-enriched subsoils, common in warm humid climates account for another 19%.
In terms of drainage, 80% of Puerto Rico soils are classified as well drained. Drainage class affects everything from septic system design to basement feasibility to garden planning. Use the survey area pages below to see drainage details for specific counties, or look up any address for an exact soil profile.
Soil Types
Inceptisols
21% of surveyed soils
Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.
Ultisols
19% of surveyed soils
Strongly weathered clay soils of the Southeast. Acidic and naturally low in nutrients. Clay subsoil can slow drainage.
Mollisols
17% of surveyed soils
Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.
Oxisols
11% of surveyed soils
Deeply weathered tropical soils. Nutrient-poor despite appearing lush. Rare in the continental US.
Entisols
9% of surveyed soils
Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.
Vertisols
7% of surveyed soils
High-clay soils that shrink and swell dramatically. Fertile but challenging for foundations and septic systems.
Alfisols
6% of surveyed soils
Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.
Aridisols
4% of surveyed soils
Dry-climate soils with low organic matter. Often have caliche layers that make excavation difficult. Low shrink-swell is good for foundations.
Histosols
1% of surveyed soils
Organic peat and muck soils formed in wetlands. Very poor for building (compressible) and septic. Often in regulated wetlands.
Survey Areas
Arecibo Area, Puerto Rico Northern PartEl Yunque National Forest, Puerto RicoHumacao Area, Puerto Rico Eastern PartMayaguez Area, Puerto Rico Western PartPonce Area, Puerto Rico Southern PartSan German Area, Southwestern Puerto RicoSan Juan Area, Puerto Rico