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LakeQuality

Lac la Belle Lake vs Oconomowoc Lake

Water quality, depth, fish species, and recreation comparison.

Oconomowoc Lake has a higher water quality grade (A, Excellent) than Lac la Belle Lake (D, Poor). Both are in Waukesha County, Wisconsin.

Both Lac la Belle Lake and Oconomowoc Lake sit in Wisconsin. A same-state comparison strips out the state-level water-quality regime as a variable: any grade differences here are about the lakes themselves, not the agencies grading them. Oconomowoc Lake (A) is materially cleaner than Lac la Belle Lake (D). A gap that wide is unlikely to close in a single year of remediation work; it reflects multi-decade differences in the lakes themselves.

For a recreational visitor, the wider grade gap is decisive — Oconomowoc Lake is the better water-quality choice. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?

D

Lac la Belle Lake

Waukesha County, Wisconsin

Murky, only visible to about 5.5 ft.

A

Oconomowoc Lake

Waukesha County, Wisconsin

Good clarity, visible to about 13 ft.

Side-by-Side Metrics

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

Source: EPA National Aquatic Resource Surveys, 2026.

MetricLac la Belle LakeOconomowoc Lake
Overall GradeD (Poor)A (Excellent)
Water Clarity5.5 ft13 ft
PhosphorusNo data11.7 µg/L
Chlorophyll-a (Algae)No dataNo data
Maximum Depth45 ft60 ft
Surface Area1.2K acres818 acres
Public AccessUnknownUnknown
Fish Species00
Trophic Stateeutrophicoligotrophic

Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).

Verdict

Oconomowoc Lake wins on overall water quality with a Grade A versus Lac la Belle Lake's Grade D. Water clarity: 13 ft vs 5.5 ft. For fishing diversity, Oconomowoc Lake also leads with 0 species.