Island of Molokai, Hawaii

Survey Area HI950• Hawaii

The dominant drainage class is Well drained and the dominant hydrologic group is C (slow infiltration, moderate runoff). The most common soil order is Oxisols — highly weathered tropical soils, deep but nutrient-poor. 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. 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
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

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.

Oxisols

Deeply weathered tropical soils. Nutrient-poor despite appearing lush. Rare in the continental US.

Mollisols

Fertile grassland soils with thick, dark topsoil. Among the best for agriculture, building, and gardening.

Ultisols

Strongly weathered clay soils of the Southeast. Acidic and naturally low in nutrients. Clay subsoil can slow drainage.

Inceptisols

Young but developing soils found in mountains and river terraces. Variable properties — check drainage and bedrock depth.

Vertisols

High-clay soils that shrink and swell dramatically. Fertile but challenging for foundations and septic systems.

Entisols

Young soils with little development — found on floodplains, dunes, and steep slopes. Properties vary widely by setting.

Andisols

Volcanic ash soils — light, porous, and fertile. Excellent drainage, but low density can complicate foundations.

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.