Soil series profile

Amwell soil series

Amwell is a somewhat poorly drained soil with a silt loam surface, mapped on 15,243 acres in 4 counties across 2 states. Hydrologic group D.

#11866 by mapped area fine-loamy Aquic Fragiudalfs (Alfisols)

Drainage class: Somewhat poorly drained
Hydrologic group: D
Typical topsoil pH: 6.1
Mapped area: 15k

Typical Amwell 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 Amwell horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–10 in (Ap)	Silt loam	6.1	15%	30%	3%
10–21 in (Bt)	Silty clay loam	5.8	28%	18%	0.75%
21–57 in (Btx)	Channery silt loam	5.8	24%	21%	0.75%
57–75 in (C)	Very channery loam	5.8	18%	43%	0.75%

Representative values from the most extensive Amwell map unit (Amwell silt loam, 3 to 8 percent slopes, survey area PA017). 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 Amwell soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Amwell soils is slightly acidic: pH 6.1 (most land between 5.6 and 6.1), the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers 100% of mapped Amwell acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (67% of mapped Amwell acres).

100% of mapped Amwell acres is somewhat poorly to very poorly drained, so soil stays soggy for long spells after rain and in wet seasons. Raised beds, plants that tolerate wet feet, and not working the soil while wet all help.

For lawns and yards

On 100% 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 100% of the acres in mapped Amwell soils very limited, 0% somewhat limited and 0% not limited.

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 Amwell soil is found

Mapped acres

Amwell is mapped in Pennsylvania and New Jersey.

Counties with the most mapped Amwell soil
County	Acres	Share of county land
Bucks County, PA	8,000	2.1%
Somerset County, NJ	4,882	2.5%
Union County, NJ	2,316	3.5%
Morris County, NJ	46	0.0%

Septic absorption fields

NRCS rating, share of Amwell acres

Not limited 0%

Somewhat limited 0%

Very limited 100%

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

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Septic tank absorption field rating across mapped Amwell acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	100.0%

Drainage, water table and flooding

Share of Amwell acres

Depth to seasonal high water table: About 1.7 feet (20 in) (median where reported).
Flooding: Not mapped as flooding on most acres.
Slope: Typically 2–6% (median 4%).
Topsoil organic matter: Median 3%.

Drainage class

Excessively drained 0%

Somewhat excessively drained 0%

Well drained 0%

Moderately well drained 0%

Somewhat poorly drained 100%

Poorly drained 0%

Very poorly drained 0%

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

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Drainage class across mapped Amwell acres.
Category	Share of acres
Excessively drained	0.0%
Somewhat excessively drained	0.0%
Well drained	0.0%
Moderately well drained	0.0%
Somewhat poorly drained	100.0%
Poorly drained	0.0%
Very poorly drained	0.0%

Hydrologic soil group

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

B: moderate infiltration 0%

C: slow infiltration 48%

D: very slow infiltration (clayey, shallow or wet) 53%

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%

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

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Hydrologic soil group across mapped Amwell acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	0.0%
C: slow infiltration	47.5%
D: very slow infiltration (clayey, shallow or wet)	52.5%
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%

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 Amwell (component kind "Series") in SSURGO: 15,243 acres.
Method: Shares are by mapped acres of Amwell components. The profile comes from the single largest Amwell component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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