Moldenhauer Lake

Moldenhauer Lake sits at the top of the Wisconsin DNR grading rubric with an A, a mark reached by the cleanest lakes in Wisconsin. Clarity, phosphorus, and chlorophyll-a all rate similarly, so there is no obvious single lever to pull on watershed management.

The lake sits in the mesotrophic zone — the band where most well-managed Wisconsin lakes fall. Moldenhauer Lake reaches 32 ft at its deepest point — typical for Wisconsin mid-sized lakes, with seasonal stratification but limited cold-water refuge. At 3 acres, Moldenhauer Lake sits below the Wisconsin median: a small water where shoreline activity has an outsized effect on water quality. Within Ozaukee County's 9 graded waters, Moldenhauer Lake sits at rank 2, near the top of the local distribution.

Moldenhauer Lake has no invasive species recorded in Wisconsin state databases as of 2024, though prevention practices still apply at all access points. The fishery is bass-led, with 3 documented species across the lake's records. The grade is based on limited monitoring — fewer than three independent measurement years contribute, so future updates may shift the letter.