How Clean Is Lake Mallalieu?
Lake Mallalieu 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): 2.8 ft. Phosphorus: 54.4 µg/L. Trophic State Index: 62.
Cleanliness Snapshot
| Metric | Lake Mallalieu | Wisconsin avg |
|---|---|---|
| Overall Grade | D | C |
| Water Clarity (Secchi) | 2.8 ft | — |
| Phosphorus | 54.4 µg/L | <30 = clean |
| Trophic State Index | 62 | <50 = clean |
How does Lake Mallalieu compare?
Lake Mallalieu's grade of D falls below the Wisconsin state average of C. It ranks #4 of 5 lakes in St. Croix County by water quality score. Multi-year monitoring data shows water quality is improving based on 6 years of records.