Lac la Belle Lake vs Oconomowoc Lake
Water quality, depth, fish species, and recreation comparison.
Lac la Belle Lake and Oconomowoc Lake both received the same overall water quality grade of B (Good). Both are in Waukesha County, Wisconsin.
Lac la Belle Lake and Oconomowoc Lake are both in Wisconsin — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. These two are within a letter of each other on the rubric — Lac la Belle Lake (B) versus Oconomowoc Lake (B). The deciding factors for a recreational visitor are likely physical (depth, access, fish species) rather than water-quality differences.
With grades this close, the choice between the two lakes turns on non-water-quality factors: depth, fish species, public access, distance from home. The per-lake pages below cover all of those.
Lac la Belle Lake
Murky, only visible to about 4.8 ft.
Oconomowoc Lake
Good clarity, visible to about 12.5 ft.
Side-by-Side Metrics
| Metric | Lac la Belle Lake | Oconomowoc Lake |
|---|---|---|
| Overall Grade | B (Good) | B (Good) |
| Water Clarity | 4.8 ft | 12.5 ft |
| Phosphorus | 14.7 µg/L | 11.9 µg/L |
| Chlorophyll-a (Algae) | No data | No data |
| Maximum Depth | 45 ft | 60 ft |
| Surface Area | 1,154 acres | 818 acres |
| Public Access | Yes | Unknown |
| Fish Species | 5 | 5 |
| Trophic State | mesotrophic | mesotrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Both lakes earn the same Grade B. The tiebreakers come down to clarity (Lac la Belle Lake: 4.8 ft, Oconomowoc Lake: 12.5 ft) and what you want from the lake. Lac la Belle Lake matches its peer on species count.
Source: EPA National Aquatic Resource Surveys, 2026.