Jasper County Lake Quality
Wisconsin, 8 lakes, average grade F (Very Poor)
Jasper County has 8 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.
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 Mariposa Lake (C); the most-stressed is Rock Creek Max Depth Lake (F).
Quick Answers for Jasper County
Planning a trip? Check special fishing regulations for Mariposa Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Jasper County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Mariposa Lake | C | 5.1 ft | - | - |
| 2 | Rock Creek Max Depth Lake | F | 1.1 ft | - | - |
| 3 | Rkcrk 4 Lake | F | 1.1 ft | - | - |
| 4 | Rkcrk 5 Lake | F | 1.1 ft | - | - |
| 5 | Rock Creek Beach Lake | F | 1.1 ft | - | - |
| 6 | Rkcrk 1 Lake | F | 1 ft | - | - |
| 7 | Rkcrk 2 Lake | F | 1.1 ft | - | - |
| 8 | Rkcrk 3 Lake | F | 1 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.