Delaware County Lake Quality
Wisconsin, 1 lakes, average grade A (Excellent)
Delaware County has 1 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, Delaware County lakes grade an A. That puts it near the top of the New York county ranking.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Somerset Lake (A) is the cleanest in the county.
Quick Answers for Delaware County
Planning a trip? Check special fishing regulations for Somerset Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Delaware County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Somerset Lake | A | 15.1 ft | - | - |
Source: EPA National Aquatic Resource Surveys, 2026.