Warren County Lake Quality
Wisconsin, 9 lakes, average grade A (Excellent)
Warren County has 9 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's average grade is A — among the cleanest in New York. 7 lakes pull an A on their own, and almost none fall into the D or F brackets.
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 Brant Lake (A); the most-stressed is Lake Forest (C).
Quick Answers for Warren County
Planning a trip? Check special fishing regulations for Brant Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Warren County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Brant Lake | A | 16.4 ft | - | - |
| 2 | Lake George | A | 26.7 ft | - | - |
| 3 | Friends Lake | A | 16.3 ft | - | - |
| 4 | Glen Lake | A | 16 ft | - | - |
| 5 | Lake Sunnyside | A | 17.8 ft | - | - |
| 6 | Lake Luzerne | A | 17.1 ft | - | - |
| 7 | Brant Lake | A | 16.4 ft | - | - |
| 8 | Friends Lake | B | 13.8 ft | - | - |
| 9 | Lake Forest | C | 8.9 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.