How Clean Is Long Lake?
Long Lake is among the cleanest lakes in Wisconsin. It received a water quality grade of A (Excellent) based on EPA monitoring data. Water clarity (Secchi depth): 32.8 ft. Phosphorus: 19.3 µg/L. Trophic State Index: 37.
Cleanliness Snapshot
| Metric | Long Lake | Wisconsin avg |
|---|---|---|
| Overall Grade | A | B |
| Water Clarity (Secchi) | 32.8 ft | — |
| Phosphorus | 19.3 µg/L | <30 = clean |
| Trophic State Index | 37 | <50 = clean |
How does Long Lake compare?
Long Lake's grade of A matches or beats the Wisconsin state average of B. It ranks #1 of 10 lakes in Fond du Lac County by water quality score. Multi-year monitoring data shows water quality is declining based on 7 years of records.