Is Boy Lake Safe for Swimming?
Boy Lake in Cass County, Minnesota has nutrient and algae measurements on record from state and federal monitoring. A water-quality reading is not a swimming clearance. The state water agency and county health departments post current advisories; check them before you swim.. Water clarity: 10.5 ft visibility. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 6.3 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Water Clarity (Secchi Depth) | 10.5 ft |
| Phosphorus | 21 μg/L |
| Chlorophyll-a (Algae) | 6.3 μg/L |
| Maximum Depth | 45 ft |
| Location | Cass County, Minnesota |
How does Boy Lake compare?
With an overall water-quality readings of —, Boy Lake matches or beats the Minnesota state average. It ranks #51 of 104 lakes in Cass County by water quality score.
Water clarity (Secchi depth) sits at 10.5 feet. That counts as exceptional clarity — sunlight penetrates deep, supporting submerged plants and limiting algae. Algae levels (chlorophyll-a) measure 6.3 µg/L — low and well within safe swimming guidelines.
Watch Boy Lake water quality
Get an email when the clarity or algae readings change. Unsubscribe anytime.