Is Mary Lake Safe for Swimming?
Mary Lake in Douglas County, Minnesota has a water quality grade of B (Good). Good for swimming, clear water with low algae levels. Water clarity: 9.8 ft visibility. Phosphorus: 19 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | B (Good) |
| Water Clarity (Secchi Depth) | 9.8 ft |
| Phosphorus | 19 μg/L |
| Maximum Depth | 40 ft |
| Location | Douglas County, Minnesota |
How does Mary Lake compare?
With an overall water quality grade of B, Mary Lake matches or beats the Minnesota state average of Grade C. It ranks #28 of 51 lakes in Douglas County by water quality score.
Water clarity (Secchi depth) sits at 9.8 feet. That puts the lake in good clarity range, with limited algae interference.