Eldorado National Forest Area, California, Parts of Alpine, Amador, El Dorado, and Placer Counties

Survey Area CA724• California

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 Inceptisols — young soils with minimal horizon development but more than Entisols. 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 Eldorado National Forest Area, California, Parts of Alpine, Amador, El Dorado, and Placer Counties. 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
Rock outcrop	123K	Excessively drained	D	Very limited	Very limited
Lithnip-Hawkinspeak-Rock outcrop complex, 30 to 75 percent slopes	43K	Well drained	D	Very limited	Very limited
McCarthy-Ledmount association, 2 to 30 percent slopes	32K	Well drained	B	Very limited	Very limited
Jocal loam, 5 to 30 percent slopes	21K	Well drained	B	Very limited	Very limited
McCarthy gravelly sandy loam, 2 to 30 percent slopes	20K	Well drained	B	Very limited	Very limited
Rock outcrop-Cryumbrepts association, 15 to 75 percent slopes	17K	Excessively drained	D	Very limited	Very limited
Chaix-Pilliken coarse sandy loam, 5 to 30 percent slopes complex	17K	Somewhat excessively drained	B	Very limited	Very limited
Lithic Xerumbrepts-Rock outcrop complex, 15 to 75 percent slopes	17K	Somewhat excessively drained	D	Very limited	Very limited
Chaix-Pilliken coarse sandy loams, 30 to 75 percent slopes complex	16K	Somewhat excessively drained	B	Very limited	Very limited
Xerumbrepts-Cryumbrepts, wet association, 5 to 50 percent slopes	16K	Moderately well drained	A	Very limited	Very limited
Tinker-Rock outcrop, granitic-Cryumbrepts, wet complex, 2 to 30 percent slopes	15K	Well drained	B	Very limited	Very limited
McCarthy gravelly sandy loam, 30 to 50 percent slopes	14K	Well drained	B	Very limited	Very limited
Lithic Cryumbrepts, 15 to 75 percent slopes	14K	Excessively drained	D	Very limited	Very limited
Chaix coarse sandy loam, 30 to 75 percent slopes	14K	Somewhat excessively drained	B	Very limited	Very limited
McCarthy-Ledmount association, 30 to 75 percent slopes	13K	Well drained	B	Very limited	Very limited
Rock outcrop, granitic-Tinker-Cryumbrepts, wet complex, 30 to 75 percent slopes	13K	Excessively drained	D	Very limited	Very limited
Water	13K		D	Not rated	Not rated
Cryumbrepts association, 5 to 50 prcent slopes	13K	Well drained	A	Very limited	Very limited
Cohasset-McCarthy association, 2 to 30 percent slopes	12K	Well drained	B	Very limited	Very limited
Tinker-Rock outcrop, granitic-Cryumbrepts, wet complex, 30 to 75 percent slopes	11K	Well drained	B	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.

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.

Ultisols

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

What This Means

Building & Foundations

About 97% 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 97% 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.