How Clean Is Lake Mendota?
Lake Mendota 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): 5 ft. Phosphorus: 50.2 µg/L. Trophic State Index: 57.
Cleanliness Snapshot
| Metric | Lake Mendota | Wisconsin avg |
|---|---|---|
| Overall Grade | C | C |
| Water Clarity (Secchi) | 5 ft | — |
| Phosphorus | 50.2 µg/L | <30 = clean |
| Trophic State Index | 57 | <50 = clean |
How does Lake Mendota compare?
Lake Mendota's grade of C matches or beats the Wisconsin state average of C. It ranks #5 of 21 lakes in Dane County by water quality score. Multi-year monitoring data shows water quality is stable based on 6 years of records.