Soil series profile

Mequon soil series

Mequon is a somewhat poorly drained soil with a silt loam surface, mapped on 22,888 acres in 4 counties in WI. Hydrologic group C.

#9708 by mapped area fine Udollic Endoaqualfs (Alfisols)

Drainage class: Somewhat poorly drained
Hydrologic group: C
Typical topsoil pH: 7.0
Mapped area: 23k

Typical Mequon 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 Mequon horizons (representative values)
Depth	Texture	pH	Clay	Sand	Organic matter
0–8 in (Ap)	Silt loam	7.0	15%	30%	3%
8–12 in (BA)	Silt loam	7.0	28%	18%	1%
12–19 in (2Bt)	Silty clay	7.0	53%	3%	0.5%
19–26 in (2BC)	Silty clay loam	7.9	48%	16%	0.3%
26–60 in (2C)	Silty clay loam	7.9	34%	18%	0.25%

Representative values from the most extensive Mequon map unit (Mequon silt loam, 1 to 3 percent slopes, survey area WI133). 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 Mequon soil means for gardens, lawns and septic systems

For gardens

Typical topsoil in Mequon soils is neutral: pH 7.0, the range most vegetables, flowers and lawn grasses prefer.

Loamy topsoil (loam, silt loam and similar) covers 99% of mapped Mequon acres: generally the easiest soil to garden, holding moisture without staying waterlogged. The most common surface texture is silt loam (99% of mapped Mequon acres).

100% of mapped Mequon 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 99% 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 99% of the acres in mapped Mequon soils very limited, 0% somewhat limited and 0% not limited (1% 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 Mequon soil is found

Mapped acres

Mequon is mapped in Wisconsin.

Counties with the most mapped Mequon soil
County	Acres	Share of county land
Waukesha County, WI	9,739	2.7%
Milwaukee County, WI	8,762	5.7%
Washington County, WI	2,575	0.9%
Ozaukee County, WI	1,812	1.2%

Septic absorption fields

NRCS rating, share of Mequon acres

Not limited 0%

Somewhat limited 0%

Very limited 99%

Not rated 1%

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

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Septic tank absorption field rating across mapped Mequon acres.
Category	Share of acres
Not limited	0.0%
Somewhat limited	0.0%
Very limited	98.9%
Not rated	1.1%

Drainage, water table and flooding

Share of Mequon acres

Depth to seasonal high water table: About 2.0 feet (24 in) (median where reported); within 18 inches on 20% of acres.
Flooding: Not mapped as flooding on most acres.
Slope: Typically 2–2% (median 2%).
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 Mequon acres. Scale 0 to 100% of mapped land.

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Drainage class across mapped Mequon 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 80%

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 19%

Not rated 1%

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

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Hydrologic soil group across mapped Mequon acres.
Category	Share of acres
A: fast infiltration (mostly sandy or gravelly)	0.0%
B: moderate infiltration	0.0%
C: slow infiltration	80.2%
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	18.7%
Not rated	1.1%

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 Mequon (component kind "Series") in SSURGO: 22,888 acres.
Method: Shares are by mapped acres of Mequon components. The profile comes from the single largest Mequon component. Full methodology.

Independent reference site. No government affiliation or endorsement.

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