Manitowoc County Lake Quality
Wisconsin, 18 lakes, average grade C (Fair)
Manitowoc County's 18 graded lakes fall in the moderate-density bracket for Wisconsin. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Cedar Lake (A); the most-stressed is Long Lake (F).
Quick Answers for Manitowoc County
Planning a trip? Check special fishing regulations for Cedar Lake, and the best times to fish — or browse the full Wisconsin regulations index.
DNR Reports (16)
Wisconsin DNR Fisheries Survey resources for lakes in Manitowoc County. Showing 12 most recent — browse all reports →
- 2024Pigeon Lake comprehensive summary survey, 2024Comprehensive Survey · WI DNR · 2024 (PDF)
- 2023Rockville Flowage spring shocking survey, 2023Spring Shocking Survey · WI DNR · 2023 (PDF)
- 2023Silver Lake comprehensive summary survey, 2023Comprehensive Survey · WI DNR · 2023 (PDF)
- 2022Cedar Lake comprehensive survey, 2022Comprehensive Survey · WI DNR · 2022 (PDF)
- 2018Shoe Lake electrofishing survey, 2018Fisheries Survey · WI DNR · 2018 (PDF)
- 2018Wilke Lake comprehensive survey 2018Comprehensive Survey · WI DNR · 2018 (PDF)
- 2017Bullhead Lake comprehensive survey 2017Comprehensive Survey · WI DNR · 2017 (PDF)
- 2017Long Lake comprehensive survey 2017Comprehensive Survey · WI DNR · 2017 (PDF)
- 2016Cedar Lake comprehensive survey 2016Comprehensive Survey · WI DNR · 2016 (PDF)
- 2015Carstens Lake spring survey 2015Fisheries Survey · WI DNR · 2015 (PDF)
- 2015East Twin River trout survey 2015Trout Survey · WI DNR · 2015 (PDF)
- 2015Point Creek bass survey 2015Fisheries Survey · WI DNR · 2015 (PDF)
All Lakes in Manitowoc County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Cedar Lake | A | 10.2 ft | - | 17.3 µg/L |
| 2 | Tuma Lake | A | 10 ft | 36 ft | 19 µg/L |
| 3 | Wilke Lake | B | 7 ft | 21 ft | 16.5 µg/L |
| 4 | Spring Lake | B | 8 ft | 23 ft | 19.6 µg/L |
| 5 | Pigeon Lake | B | 9.3 ft | 62 ft | 15.4 µg/L |
| 6 | Little Pigeon Lake | B | - | 14.5 ft | 20 µg/L |
| 7 | Shoe Lake | B | 7 ft | 34 ft | 26.6 µg/L |
| 8 | English Lake | B | 7.5 ft | - | 26.7 µg/L |
| 9 | Kasbaum Lake | B | 9.7 ft | 68 ft | 22.2 µg/L |
| 10 | Hartlaub Lake | C | 5 ft | 60 ft | 35.8 µg/L |
| 11 | Horseshoe Lake | C | 6.5 ft | 54 ft | 36.2 µg/L |
| 12 | Harpt Lake | C | 3.5 ft | 54 ft | 44.2 µg/L |
| 13 | Bullhead Lake | D | 4.3 ft | 40 ft | 82.7 µg/L |
| 14 | Gass Lake | D | 6 ft | 24 ft | 62.9 µg/L |
| 15 | Weyers Lake | D | 6 ft | 32 ft | 92.3 µg/L |
| 16 | Carstens Lake | D | 5.2 ft | - | 92.6 µg/L |
| 17 | Long Lake | F | 1.9 ft | 38 ft | 90.4 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.