Is Cass Lake Safe for Swimming?
Cass Lake in Beltrami County, Minnesota has a water quality grade of A (Excellent). Excellent for swimming, crystal clear water with minimal algae. Water clarity: 18.5 ft visibility. Chlorophyll-a (algae): 3.2 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | A (Excellent) |
| Water Clarity (Secchi Depth) | 18.5 ft |
| Chlorophyll-a (Algae) | 3.2 μg/L |
| Maximum Depth | 120 ft |
| Location | Beltrami County, Minnesota |
How does Cass Lake compare?
With an overall water quality grade of A, Cass Lake matches or beats the Minnesota state average of Grade C. It ranks #18 of 92 lakes in Beltrami County by water quality score.
Water clarity (Secchi depth) sits at 18.5 feet. That counts as exceptional clarity — sunlight penetrates deep, supporting submerged plants and limiting algae. Algae levels (chlorophyll-a) measure 3.2 µg/L — low and well within safe swimming guidelines.