Juneau County Lake Quality
Wisconsin, 2 lakes, average grade D (Poor)
Juneau County has 2 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. On average, Juneau County lakes grade D, with phosphorus loading and reduced clarity showing up across most of the dataset.
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 Petenwell Flowage Lake (C); the most-stressed is Decorah Lake (D).
Quick Answers for Juneau County
Planning a trip? Check special fishing regulations for Petenwell Flowage Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Juneau County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Petenwell Flowage Lake | C | 7.8 ft | 44 ft | 81.7 µg/L |
| 2 | Decorah Lake | D | 7.4 ft | 15 ft | 116 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.