Monroe County Lake Quality
Wisconsin, 1 lakes, average grade F (Very 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 average is F — the most-stressed bracket in our rubric. Most monitored lakes here show persistent nutrient loading and algal pressure.
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 (F) 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 | F | - | 19 ft | 140 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.