Is Big Deep Lake Safe for Swimming?
Big Deep Lake in Cass County, Minnesota has a water quality grade of A (Excellent). Excellent for swimming, crystal clear water with minimal algae. Water clarity: 17.1 ft visibility. Phosphorus: 6.5 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | A (Excellent) |
| Water Clarity (Secchi Depth) | 17.1 ft |
| Phosphorus | 6.5 μg/L |
| Maximum Depth | 107 ft |
| Location | Cass County, Minnesota |
How does Big Deep Lake compare?
With an overall water quality grade of A, Big Deep Lake matches or beats the Minnesota state average of Grade C. It ranks #44 of 133 lakes in Cass County by water quality score.
Water clarity (Secchi depth) sits at 17.1 feet. That counts as exceptional clarity — sunlight penetrates deep, supporting submerged plants and limiting algae.