Waukesha County Lake Quality
Wisconsin, 45 lakes, average grade B (Good)
There are 45 graded lakes in Waukesha County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. With an average grade of B, Waukesha County sits comfortably above the Wisconsin median.
Many of the county's lakes are deep glacial basins — over 50 feet at their deepest point — which gives them thermal stratification and a buffer against summer warming. Spring Lake (grade A) is the cleanest in the county.
Quick Answers for Waukesha County
Planning a trip? Check special fishing regulations for Spring Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
DNR Reports (3)
Wisconsin DNR Fisheries Survey resources for lakes in Waukesha County. browse all reports →
- 2024Upper Genesee Lake fall shocking survey, 2024Fisheries Survey · WI DNR · 2024 (PDF)
- 2023Lake Keesus spring shocking survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
- 2023Middle Genesee Lake spring shocking survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
All Lakes in Waukesha County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Spring Lake | A | - | 22 ft | 12.2 µg/L |
| 2 | Pine Lake | A | 25 ft | 85 ft | 11.9 µg/L |
| 3 | Moose Lake | A | 16 ft | - | - |
| 4 | Little Muskego Lake | A | 15.5 ft | 65 ft | - |
| 5 | Okauchee Lake | A | 11.3 ft | 90 ft | 18 µg/L |
| 6 | Silver Lake | A | 10 ft | 40 ft | 11.8 µg/L |
| 7 | Ashippun Lake | A | 10 ft | 35 ft | 12.8 µg/L |
| 8 | Ottawa Lake | A | 13 ft | 16 ft | 15 µg/L |
| 9 | Pretty Lake | A | 12.2 ft | 31 ft | 12.2 µg/L |
| 10 | Oconomowoc Lake | A | 13 ft | 60 ft | 11.7 µg/L |
| 11 | Oconomowoc Lake Site | A | 13 ft | 60 ft | 13.8 µg/L |
| 12 | Lower Nemahbin Lake | A | 10.9 ft | - | 11 µg/L |
| 13 | Fowler Lake | A | 14.5 ft | 50 ft | 15.6 µg/L |
| 14 | Upper Nemahbin Lake | A | 12 ft | 60 ft | 13.7 µg/L |
| 15 | Okauchee Lake | A | 12 ft | 90 ft | 17.1 µg/L |
| 16 | Golden Lake | A | 12.8 ft | 44 ft | 14.1 µg/L |
| 17 | Crooked Lake | B | 7.9 ft | 16 ft | 16.5 µg/L |
| 18 | North Lake | B | 8 ft | 78.4 ft | 17.9 µg/L |
| 19 | Pewaukee Lake | B | 7.5 ft | 45 ft | 19.9 µg/L |
| 20 | Hunters Lake | B | 9.5 ft | 36 ft | 15.9 µg/L |
| 21 | Lake Keesus | B | 9.2 ft | 42 ft | 15.8 µg/L |
| 22 | Lower Nashotah Lake | B | 9 ft | 43 ft | 11.3 µg/L |
| 23 | Nagawicka Lake | B | 9.5 ft | 90 ft | 13.5 µg/L |
| 24 | Lower Phantom Lake | B | 6.7 ft | 12 ft | 15.7 µg/L |
| 25 | Upper Nemahbin Lake | B | 12 ft | 60 ft | - |
| 26 | Lac la Belle Lake | B | 4.8 ft | 45 ft | 14.7 µg/L |
| 27 | Eagle Spring Lake | B | 4.3 ft | 8 ft | 17.9 µg/L |
| 28 | Denoon Lake | B | 9 ft | 55 ft | 25.3 µg/L |
| 29 | Okauchee Lake Site | B | 5.9 ft | 90 ft | 19 µg/L |
| 30 | Okauchee Lake Deep Hole Usgs | B | 7.5 ft | 90 ft | 23.7 µg/L |
| 31 | Ocauchee Lake | B | 6.6 ft | 90 ft | 17.5 µg/L |
| 32 | School Section Lake | C | 6.2 ft | 8 ft | 26.2 µg/L |
| 33 | North Lake West Basin | C | 9.5 ft | 78.4 ft | - |
| 34 | Muskego Lake | C | - | 23 ft | 59.4 µg/L |
| 35 | Lapham Peak Pond | D | 5 ft | - | - |
| 36 | Lac la Belle Lake | D | 5.5 ft | 45 ft | - |
| 37 | Henrietta Lake | D | 4.5 ft | 7 ft | - |
| 38 | Upper Kelly Lake | F | 2 ft | 31 ft | - |
| 39 | Lower Kelly Lake | F | - | 36 ft | 156 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.