Is Green Lake Safe for Swimming?
Green Lake in Chisago County, Minnesota has a water quality grade of C (Fair). Generally safe for swimming, moderate water quality. Water clarity: 6 ft visibility. Phosphorus: 23 µg/L. Chlorophyll-a (algae): 8.4 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | C (Fair) |
| Water Clarity (Secchi Depth) | 6 ft |
| Phosphorus | 23 μg/L |
| Chlorophyll-a (Algae) | 8.4 μg/L |
| Maximum Depth | 32 ft |
| Location | Chisago County, Minnesota |
How does Green Lake compare?
With an overall water quality grade of C, Green Lake matches or beats the Minnesota state average of Grade C. It ranks #13 of 30 lakes in Chisago County by water quality score.
Water clarity (Secchi depth) sits at 6 feet. That puts the lake in good clarity range, with limited algae interference. Algae levels (chlorophyll-a) measure 8.4 µg/L — moderate; acceptable for swimming on most days, but worth checking advisories.