Johnson County Lake Quality
Wisconsin, 3 lakes, average grade D (Poor)
Only 3 lakes in Johnson County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. On average, Johnson 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 Kent Park Lake (C); the most-stressed is Terry Trueblood Lake (F).
Quick Answers for Johnson County
Planning a trip? Check special fishing regulations for Kent Park Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Johnson County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Kent Park Lake | C | 4.8 ft | - | - |
| 2 | Lake Macbride | D | 2.9 ft | - | - |
| 3 | Terry Trueblood Lake | F | 1.1 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.