Is Boulder Lake Safe for Swimming?
Boulder Lake in Vilas County, Wisconsin has a water quality grade of A (Excellent). Excellent for swimming, crystal clear water with minimal algae. Water clarity: 18.9 ft visibility. Phosphorus: 21.6 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | A (Excellent) |
| Water Clarity (Secchi Depth) | 18.9 ft |
| Phosphorus | 21.6 μg/L |
| Maximum Depth | 23 ft |
| Location | Vilas County, Wisconsin |
How does Boulder Lake compare?
With an overall water quality grade of A, Boulder Lake matches or beats the Wisconsin state average of Grade B. It ranks #156 of 202 lakes in Vilas County by water quality score.
Water clarity (Secchi depth) sits at 18.9 feet. That counts as exceptional clarity — sunlight penetrates deep, supporting submerged plants and limiting algae.