McLean County Lake Quality
Wisconsin, 3 lakes, average grade B (Good)
Only 3 lakes in McLean 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. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.
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 Garlk1445dw Lake (B); the most-stressed is Custer Mine Pond (C).
Quick Answers for McLean County
Planning a trip? Check special fishing regulations for Garlk1445dw Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in McLean County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Garlk1445dw Lake | B | 11.7 ft | - | 10 µg/L |
| 2 | Lake Audubon | B | 4.7 ft | - | - |
| 3 | Custer Mine Pond | C | 2.2 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.