Soil series profile

Charcol soil series

Charcol is a well drained soil with a gravelly fine sandy loam surface, mapped on 34,944 acres in 5 counties across 2 states. Hydrologic group B.

#7594 by mapped area loamy-skeletal Cryic Pachic Paleborolls (Mollisols)

Drainage class: Well drained
Hydrologic group: B
Typical topsoil pH: 6.3
Mapped area: 35k

Typical Charcol profile

Texture and pH by depth

Depth to scale. More strongly shaded layers hold more clay. Horizon names are the soil survey's (A = topsoil, B = subsoil, C = parent material).

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Typical Charcol horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–13 in (A11)	Gravelly fine sandy loam	6.3	14%	70%	3.5%
13–21 in (A12)	Very gravelly fine sandy loam	6.3	14%	70%	3.5%
21–30 in (A21)	Extremely gravelly sandy loam	6.3	10%	67%	0.75%
30–38 in (A22)	Extremely gravelly loamy fine sand	6.3	10%	81%	0.75%
38–44 in (A&B)	Not reported	6.3	10%	81%	0.75%
44–54 in (B2t)	Very gravelly loam	6.3	23%	40%	0.75%
54–62 in (C)	Very gravelly sandy loam	6.3	14%	67%	0.75%

Representative values from the most extensive Charcol map unit (Charcol gravelly fine sandy loam, 30 to 50 percent slopes, survey area UT609). Other map units of this series vary within the series range.

Stock photo for illustration, not a sample of this soil series. Credit on the Sources & method page.

What this means

What Charcol soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Charcol soils is slightly acidic: pH 6.3, the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers 91% of mapped Charcol acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is gravelly fine sandy loam (90% of mapped Charcol acres).

91% of mapped Charcol acres is moderately well to excessively drained, which suits most garden plants.

For lawns and yards

Most land is in hydrologic groups B and C, where rain soaks in at a moderate pace.

For a septic system

For conventional septic absorption fields, NRCS rates 91% of the acres in mapped Charcol soils very limited, 0% somewhat limited and 0% not limited (9% not rated, such as urban land, pits or water).

Where the soil is very limited (slow permeability, a high water table, flooding, shallow bedrock or steep slopes), alternative systems such as mound or sand-filter designs are common and cost more.

Only a licensed site evaluation or perc test at the actual lot decides whether a system is allowed and which design.

Generated from the mapped numbers above using fixed rules, not a site visit. See how these notes are written.

Where Charcol soil is found

Mapped acres

Charcol is mapped in Utah and Colorado.

Counties with the most mapped Charcol soil
County	Acres	Share of county land
Morgan County, UT	21,628	5.6%
Weber County, UT	12,760	3.7%
Eagle County, CO	502	0.1%
Garfield County, CO	27	0.0%
Pitkin County, CO	27	0.0%

Septic absorption fields

NRCS rating, share of Charcol acres

Not limited 0%

Somewhat limited 0%

Very limited 91%

Not rated 9%

Septic tank absorption field rating across mapped Charcol acres. Scale 0 to 100% of mapped land.

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Septic tank absorption field rating across mapped Charcol acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	91.4%
Not rated	8.6%

Drainage, water table and flooding

Share of Charcol acres

Depth to seasonal high water table: None reported within about 6.5 feet (median where reported).
Flooding: Not mapped as flooding on most acres.
Slope: Typically 40–40% (median 40%).
Topsoil organic matter: Median 3.5%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained 91%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Not rated 9%

Drainage class across mapped Charcol acres. Scale 0 to 100% of mapped land.

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Drainage class across mapped Charcol acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	91.4%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	8.6%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 2%

B: moderate infiltration 90%

C: slow infiltration 0%

D: very slow infiltration (clayey, shallow or wet) 0%

A/D: D as is, A if drained 0%

B/D: D as is, B if drained 0%

C/D: D as is, C if drained 0%

Not rated 9%

Hydrologic soil group across mapped Charcol acres. Scale 0 to 100% of mapped land.

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Hydrologic soil group across mapped Charcol acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	1.6%
B: moderate infiltration	89.8%
C: slow infiltration	0.0%
D: very slow infiltration (clayey, shallow or wet)	0.0%
A/D: D as is, A if drained	0.0%
B/D: D as is, B if drained	0.0%
C/D: D as is, C if drained	0.0%
Not rated	8.6%

Sources & data dates

Source: USDA NRCS Soil Survey Geographic Database (SSURGO), queried through Soil Data Access. Public domain.
Data date: SSURGO as published on November 3, 2026 (most recent survey area update October 26, 2026). NRCS refreshes SSURGO each October.
Scope: All map unit components named Charcol (component kind "Series") in SSURGO: 34,944 acres.
Method: Shares are by mapped acres of Charcol components. The profile comes from the single largest Charcol component. Full methodology.

Independent reference site. No government affiliation or endorsement.

Full narrative description: USDA Official Soil Series Description for Charcol.