Monroe County Lake Quality
Wisconsin, 1 lakes, average grade D (Poor)
Monroe County has 1 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. The county-wide average grade is D — water quality issues are persistent across most of the monitored basins. 0 lakes fall into the F bracket outright.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Lake Tomah (D) is the cleanest in the county.
Quick Answers for Monroe County
Planning a trip? Check special fishing regulations for Lake Tomah, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
DNR Reports (5)
Wisconsin DNR Fisheries Survey resources for lakes in Monroe County. browse all reports →
- 2025Lake Tomah fish age and growth, 2025Fisheries Survey · WI DNR · 2025 (PDF)
- 2025Lake Tomah shocking and netting survey, 2025Netting Survey · WI DNR · 2025 (PDF)
- 2025Lake Wazeda netting survey, 2025Netting Survey · WI DNR · 2025 (PDF)
- 2019Perch Lake Fisheries Survey, 2019Fisheries Survey · WI DNR · 2019 (PDF)
- —Lake Tomah comprehensive survey, 2017-2022Comprehensive Survey · WI DNR (PDF)
All Lakes in Monroe County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Lake Tomah | D | 4.9 ft | 19 ft | 140 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.