How Clean Is Green Lake?
Green Lake has fair water quality — typical of lakes with moderate nutrient enrichment. It received a water quality grade of C (Fair) based on EPA monitoring data. Water clarity (Secchi depth): 11.5 ft. Phosphorus: 66.5 µg/L. Trophic State Index: 53.
Cleanliness Snapshot
| Metric | Green Lake | Wisconsin avg |
|---|---|---|
| Overall Grade | C | C |
| Water Clarity (Secchi) | 11.5 ft | — |
| Phosphorus | 66.5 µg/L | <30 = clean |
| Trophic State Index | 53 | <50 = clean |
How does Green Lake compare?
Green Lake's grade of C matches or beats the Wisconsin state average of C. It ranks #6 of 13 lakes in Green Lake County by water quality score. Multi-year monitoring data shows water quality is improving based on 3 years of records.