How Clean Is St. Croix Lake?
St. Croix Lake 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): 4.4 ft. Trophic State Index: 56.
Cleanliness Snapshot
| Metric | St. Croix Lake | Wisconsin avg |
|---|---|---|
| Overall Grade | D | B |
| Water Clarity (Secchi) | 4.4 ft | — |
| Trophic State Index | 56 | <50 = clean |
How does St. Croix Lake compare?
St. Croix Lake's grade of D falls below the Wisconsin state average of B. It ranks #7 of 7 lakes in St. Croix County by water quality score. Multi-year monitoring data shows water quality is declining based on 6 years of records.