How Clean Is Lake St. Croix?
Lake St. Croix is a clean lake by Wisconsin standards. It received a water quality grade of B (Good) based on EPA monitoring data. Water clarity (Secchi depth): 5.6 ft. Phosphorus: 16.5 µg/L. Trophic State Index: 48.
Cleanliness Snapshot
| Metric | Lake St. Croix | Wisconsin avg |
|---|---|---|
| Overall Grade | B | B |
| Water Clarity (Secchi) | 5.6 ft | — |
| Phosphorus | 16.5 µg/L | <30 = clean |
| Trophic State Index | 48 | <50 = clean |
How does Lake St. Croix compare?
Lake St. Croix's grade of B matches or beats the Wisconsin state average of B. It ranks #3 of 7 lakes in St. Croix County by water quality score. Multi-year monitoring data shows water quality is improving based on 2 years of records.