Is Colby Lake Safe for Swimming?
Colby Lake in St. Louis County, Minnesota has a water quality grade of C (Fair). Generally safe for swimming, moderate water quality. Water clarity: 3.5 ft visibility. Phosphorus: 22 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | C (Fair) |
| Water Clarity (Secchi Depth) | 3.5 ft |
| Phosphorus | 22 μg/L |
| Maximum Depth | 30 ft |
| Location | St. Louis County, Minnesota |
How does Colby Lake compare?
With an overall water quality grade of C, Colby Lake matches or beats the Minnesota state average of Grade C. It ranks #95 of 187 lakes in St. Louis County by water quality score.
Water clarity (Secchi depth) sits at 3.5 feet. That falls into moderate clarity — typical for lakes with some nutrient enrichment.