How Clean Is Lake Mendota?
Lake Mendota has poor water quality, with elevated phosphorus and algae. It received a water quality grade of D (Poor) based on EPA monitoring data. Water clarity (Secchi depth): 5 ft. Phosphorus: 65.4 µg/L. Trophic State Index: 59.
Cleanliness Snapshot
| Metric | Lake Mendota | Wisconsin avg |
|---|---|---|
| Overall Grade | D | B |
| Water Clarity (Secchi) | 5 ft | — |
| Phosphorus | 65.4 µg/L | <30 = clean |
| Trophic State Index | 59 | <50 = clean |
How does Lake Mendota compare?
Lake Mendota's grade of D falls below the Wisconsin state average of B. It ranks #9 of 15 lakes in Dane County by water quality score. Multi-year monitoring data shows water quality is declining based on 7 years of records.