Petroleum County, Montana

Survey Area MT069• Montana

The dominant drainage class is Well drained and the dominant hydrologic group is D (very slow infiltration, high runoff). The most common soil order is Entisols — young soils with little profile development, often on floodplains or steep slopes. 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 Petroleum County, Montana. 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
Gerdrum-Vanda-Creed complex, 0 to 8 percent slopes	71K	Well drained	D	Very limited	Not limited
Bascovy-Neldore-Neldore, moist, silty clays, 6 to 60 percent slopes	55K	Well drained	D	Very limited	Very limited
Cabbart, moist-Blacksheep-Delpoint, calcareous complex, 6 to 60 percent slopes	41K	Well drained	D	Very limited	Very limited
Neldore-Bascovy-Rock outcrop complex, 6 to 60 percent slopes	39K	Well drained	D	Very limited	Very limited
Cabbart-Yawdim-Rock outcrop complex, 4 to 35 percent slopes	37K	Well drained	D	Very limited	Very limited
Neldore, moist-Bascovy-Neldore, dry, silty clays, 6 to 60 percent slopes	35K	Well drained	D	Very limited	Very limited
Delpoint-Cabbart-Yamac loams, 4 to 15 percent slopes	34K	Well drained	C	Somewhat limited	Very limited
Gerdrum-Vanda complex, 1 to 6 percent slopes	31K	Well drained	D	Very limited	Not limited
Gerdrum-Creed complex, 1 to 6 percent slopes	31K	Well drained	D	Very limited	Not limited
Neldore-Abor silty clays, 15 to 45 percent slopes	29K	Well drained	D	Very limited	Very limited
Evanston loam, 2 to 8 percent slopes	26K	Well drained	B	Somewhat limited	Somewhat limited
Neldore-Abor silty clays, 4 to 15 percent slopes	26K	Well drained	D	Very limited	Very limited
Bascovy-Neldore silty clays, 2 to 15 percent slopes	23K	Well drained	D	Very limited	Very limited
Neldore-Rock outcrop complex, 15 to 60 percent slopes	22K	Well drained	D	Very limited	Very limited
Yawdim-Orinoco complex, 4 to 15 percent slopes	21K	Well drained	D	Very limited	Very limited
Cabbart-Delpoint-Cabbart, moist, loams, calcareous 4 to 35 percent slopes	21K	Well drained	D	Very limited	Very limited
Verson clay loam, 0 to 4 percent slopes	21K	Well drained	C	Not limited	Very limited
Neldore-Volborg silty clays, 4 to 25 percent slopes	20K	Well drained	D	Very limited	Very limited
Twilight-Blacksheep sandy loams, 2 to 8 percent slopes	18K	Well drained	B	Somewhat limited	Very limited
Yawdim-Crago complex, 4 to 35 percent slopes	16K	Well drained	D	Very 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.

Entisols

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

Inceptisols

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

Alfisols

Moderately weathered forest soils with clay-enriched subsoil. Productive for agriculture, generally good for building and septic.

What This Means

Building & Foundations

About 84% of soils are rated "very limited" for dwellings with basements. Specific challenges include shallow bedrock, steep slopes. A geotechnical assessment is recommended before building.

Septic Systems

About 74% 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.