Soil series profile

Amtoft soil series

Amtoft is a somewhat excessively drained soil with a very cobbly loam surface, mapped on 498,420 acres in 11 counties across 2 states. Hydrologic group D.

#563 by mapped area loamy-skeletal Lithic Xeric Haplocalcids (Aridisols)

Drainage class: Somewhat excessively drained
Hydrologic group: D
Typical topsoil pH: 8.5
Mapped area: 498k

Typical Amtoft 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 Amtoft horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–9 in (A,Bw)	Very cobbly loam	8.5	15%	44%	1.5%
9–16 in (Bk)	Extremely cobbly loam	8.5	16%	44%	0.5%
16–26 in (R)	Bedrock	Not reported	Not reported	Not reported	Not reported

Representative values from the most extensive Amtoft map unit (Amtoft-Rock outcrop complex, 30 to 70 percent slopes, survey area UT611). 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 Amtoft soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Amtoft soils is strongly alkaline: pH 8.5. Acid-loving plants such as blueberries and azaleas struggle without amended beds, and some trees and shrubs show iron chlorosis (yellow leaves with green veins).

Loamy topsoil (loam, silt loam and similar) covers 97% of mapped Amtoft acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is very cobbly loam (51% of mapped Amtoft acres).

63% of mapped Amtoft acres is excessively or somewhat excessively drained: water moves through fast, so gardens need more frequent watering in dry spells.

For lawns and yards

On 97% of mapped acres, rain soaks in slowly (hydrologic groups C and D, including dual groups that are D until drained). Expect runoff and puddles after heavy rain: core-aerate compacted lawns and keep ground sloping away from foundations.

For a septic system

For conventional septic absorption fields, NRCS rates 97% of the acres in mapped Amtoft soils very limited, 0% somewhat limited and 0% not limited (3% 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 Amtoft soil is found

Mapped acres

Amtoft is mapped in Utah and Nevada.

Counties with the most mapped Amtoft soil
County	Acres	Share of county land
Tooele County, UT	211,503	4.8%
White Pine County, NV	74,026	1.3%
Elko County, NV	73,207	0.7%
Box Elder County, UT	38,687	1.1%
Sanpete County, UT	30,697	4.8%
Utah County, UT	25,809	2.5%
Juab County, UT	15,440	1.7%
Lincoln County, NV	9,951	0.2%
Sevier County, UT	8,713	2.1%
Millard County, UT	5,763	0.5%
Nye County, NV	1,179	0.0%

Septic absorption fields

NRCS rating, share of Amtoft acres

Not limited 0%

Somewhat limited 0%

Very limited 97%

Not rated 3%

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

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Septic tank absorption field rating across mapped Amtoft acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	96.9%
Not rated	3.1%

Drainage, water table and flooding

Share of Amtoft 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 33–50% (median 50%).
Topsoil organic matter: Median 1.5%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 63%

Well drained 34%

Moderately well drained 0%

Somewhat poorly drained 0%

Poorly drained 0%

Very poorly drained 0%

Not rated 3%

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

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Drainage class across mapped Amtoft acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	63.0%
Well drained	33.9%
Moderately well drained	0.0%
Somewhat poorly drained	0.0%
Poorly drained	0.0%
Very poorly drained	0.0%
Not rated	3.1%

Hydrologic soil group

A: fast infiltration (mostly sandy or gravelly) 0%

B: moderate infiltration 0%

C: slow infiltration 0%

D: very slow infiltration (clayey, shallow or wet) 97%

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 3%

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

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Hydrologic soil group across mapped Amtoft acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	0.0%
C: slow infiltration	0.0%
D: very slow infiltration (clayey, shallow or wet)	96.9%
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	3.1%

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 Amtoft (component kind "Series") in SSURGO: 498,420 acres.
Method: Shares are by mapped acres of Amtoft components. The profile comes from the single largest Amtoft component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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