Adair County Lake Quality
Wisconsin, 5 lakes, average grade C (Fair)
Only 5 lakes in Adair 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 average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
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. Forest Lake (B) is the cleanest in the county.
Quick Answers for Adair County
Planning a trip? Check special fishing regulations for Forest Lake, whether the fish are safe to eat, and the best times to fish — or browse the full Wisconsin regulations index.
All Lakes in Adair County
| Rank | Lake | Grade | Clarity | Max Depth | Phosphorus |
|---|---|---|---|---|---|
| 1 | Forest Lake | B | 4.1 ft | - | 18 µg/L |
| 2 | Hazel Creek Lk. Lake | C | 3.6 ft | - | 24.5 µg/L |
| 3 | Forest Lake Se Branch | C | 2.3 ft | - | 25 µg/L |
| 4 | Hazel Creek Lk. Lake | C | 2.8 ft | - | 22 µg/L |
| 5 | Hazel Creek Lk. East Fork Lake | D | 2.6 ft | - | 31.5 µg/L |
Source: EPA National Aquatic Resource Surveys, 2026.