Walworth County Lake Quality
Wisconsin, 34 lakes, average grade C (Fair)
There are 34 graded lakes in Walworth County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. Walworth County averages to a C. The distribution behind that average matters more than the letter: a few stressed lakes versus many decent ones can produce the same average as the inverse.
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. Geneva Lake (grade A) is the cleanest in the county.
Quick Answers for Walworth County
Planning a trip? Check special fishing regulations for Geneva Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
DNR Reports (2)
Wisconsin DNR Fisheries Survey resources for lakes in Walworth County. browse all reports →
- 2023Lauderdale Lakes Chain comprehensive survey, 2023Comprehensive Survey · WI DNR · 2023 (PDF)
- 2021Turtle Lake spring shocking survey, 2017, 2021Spring Shocking Survey · WI DNR · 2021 (PDF)
All Lakes in Walworth County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Geneva Lake | A | 20.2 ft | 135 ft | 13 µg/L |
| 2 | Geneva Lake | A | 20.7 ft | 135 ft | 13.4 µg/L |
| 3 | Geneva Lake Site B | A | 24.1 ft | 135 ft | 12.9 µg/L |
| 4 | Lake Beulah | A | 11 ft | 58 ft | 13 µg/L |
| 5 | Pleasant Lake | A | 12 ft | 29 ft | 15.1 µg/L |
| 6 | Green Lake | A | 11.5 ft | 57 ft | 10.5 µg/L |
| 7 | Turtle Lake | A | 11.3 ft | 30 ft | 14.5 µg/L |
| 8 | Middle Lake | A | 10 ft | 40 ft | 12.3 µg/L |
| 9 | Lake Beulah | A | 10 ft | 58 ft | 13.4 µg/L |
| 10 | Booth Lake | B | 8 ft | 24 ft | 16.4 µg/L |
| 11 | Mill Lake | B | 7.5 ft | 40 ft | 15.3 µg/L |
| 12 | Army Lake | B | 8.2 ft | 17 ft | 11.2 µg/L |
| 13 | Delavan Lake | B | - | 52 ft | 25.9 µg/L |
| 14 | Delavan Lake | B | 9.3 ft | 52 ft | 26.5 µg/L |
| 15 | Delavan Lake | B | 9.1 ft | 52 ft | 27 µg/L |
| 16 | Peters Lake | B | 5.6 ft | 8 ft | 19.6 µg/L |
| 17 | Delavan Lake | C | 10 ft | 52 ft | 73 µg/L |
| 18 | Pickerel Lake | C | 8.5 ft | 31 ft | - |
| 19 | Delavan Lake | C | 8 ft | 52 ft | 49.5 µg/L |
| 20 | Whitewater Lake | C | 4 ft | 35 ft | 26.2 µg/L |
| 21 | Swan Lake | C | 6.8 ft | 7 ft | - |
| 22 | Lake Lorraine | C | - | 8 ft | 54.1 µg/L |
| 23 | Potter Lake | C | - | 26 ft | 35 µg/L |
| 24 | Potter Lake | C | 4.3 ft | 26 ft | 35 µg/L |
| 25 | Rice Lake | D | 1.5 ft | 10 ft | 57.2 µg/L |
| 26 | North Lake | D | 3.5 ft | 11 ft | - |
| 27 | Lake Wandawega | D | 6 ft | 8 ft | - |
| 28 | Swift Lake | D | 6 ft | - | - |
| 29 | Silver Lake | F | 3 ft | 3 ft | - |
| 30 | Comus Lake | F | 1.5 ft | 6 ft | 193 µg/L |
| 31 | Honey Lake | F | 2.5 ft | 6 ft | 99 µg/L |
| 32 | Lake Ivanhoe | F | 2.5 ft | 10 ft | - |
| 33 | Outlet To Lake Geneva | F | - | 135 ft | 734.5 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.