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LakeQuality
C

Muskego Lake

Waukesha County, WisconsinLimited DataEutrophic

Muskego Lake earns a C — middle-of-the-pack water quality, with one or two parameters dragging the average down from a stronger grade. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

At a TSI of 63, Muskego Lake reads as eutrophic — nutrient-rich enough that summer algal growth and reduced clarity are expected, not unusual. A maximum depth of 23 ft puts Muskego Lake in the middle of Wisconsin's depth distribution. At 2,194 acres, Muskego Lake is one of the larger lakes in Waukesha County, with partial shoreline records supporting multiple distinct use patterns. Within the 48 graded lakes of Waukesha County, Muskego Lake sits at rank 46, near the bottom of the county list.

Eurasian watermilfoil has been documented at Muskego Lake, requiring shoreline management to keep dense mats from crowding native vegetation. The fishery is bass-led, with 3 documented species across the lake's records. A documented public access point at Muskego Lake makes the lake usable for shore fishing, paddle craft, and trailered boats. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.

Source: EPA Water Quality Portal sampling records, Wisconsin DNR Surface Water, last sampled 2022-05-11. Grade methodology: LakeGrade methodology.

Swimming Safety

Generally safe for swimming, moderate water quality

Water Quality Grade: C, Fair

No clarity data. Phosphorus level: 59.4 µg/L. Trophic State Index: 63.

MetricValueGrade
Water Clarity (Secchi Depth)No data
Phosphorus59.4 µg/LC
Chlorophyll-a (Algae)No data
Trophic State Index (TSI)63Eutrophic

High nutrients, frequent algae, reduced clarity

Lake Details

CharacteristicValue
Maximum Depth23 ft
Surface Area2.2K acres
Public AccessYes

Fish Species

Click a species to see all Wisconsin and Minnesota lakes where it is found.

→ Best fishing times for Muskego Lake (14-day solunar calendar)

→ Is it safe to eat fish from Muskego Lake? (mercury & PFAS guide)

Muskego Lake fishing regulations (limits, seasons, special rules)

Invasive Species

Curly-Leaf PondweedEurasian Water-MilfoilPurple LoosestrifeStarry Stonewort

Water Quality Trend: Declining

Based on 2 years of monitoring data (2020-2025).

MetricTrendChange/YearYears
Phosphorus Declining+91.2 µg/L/yr2
See year-by-year chart →

Recreation & Access

2
Boat Landings
Yes
Public Access

Location

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County Ranking

Ranked #46 of 48 lakes in Waukesha County

Cleaner Lakes Within 30 Miles

Muskego Lake holds Grade C. 2 nearby lakes hold higher grades.

See full comparison →

Nearby Lakes in Waukesha County

Eutrophic Lakes in Wisconsin

WI DNR Lake Profile

Authoritative data from the Wisconsin DNR LakePages. 32 stations on file (most recent sample 2023).

Fish Species (DNR-rated)

Largemouth Bass(Common)Panfish(Present)Northern Pike(Present)

Data Sources

Water quality data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Fish and recreation data from Wisconsin DNR Lakes

Most recent sample: 2022-05-11

Monitoring stations: 1