How Clean Is Long Lake?
Long Lake is a clean lake by Wisconsin standards. It received a water quality grade of B (Good) based on EPA monitoring data. Water clarity (Secchi depth): 9.1 ft. Phosphorus: 19.3 µg/L. Trophic State Index: 46.
Cleanliness Snapshot
| Metric | Long Lake | Wisconsin avg |
|---|---|---|
| Overall Grade | B | C |
| Water Clarity (Secchi) | 9.1 ft | — |
| Phosphorus | 19.3 µg/L | <30 = clean |
| Trophic State Index | 46 | <50 = clean |
How does Long Lake compare?
Long Lake's grade of B matches or beats the Wisconsin state average of C. It ranks #4 of 10 lakes in Fond du Lac County by water quality score. Multi-year monitoring data shows water quality is declining based on 6 years of records.