How Clean Is Boulder Lake?
Boulder Lake is among the cleanest lakes in Wisconsin. It received a water quality grade of A (Excellent) based on EPA monitoring data. Water clarity (Secchi depth): 18.9 ft. Phosphorus: 21.6 µg/L. Trophic State Index: 42.
Cleanliness Snapshot
| Metric | Boulder Lake | Wisconsin avg |
|---|---|---|
| Overall Grade | A | B |
| Water Clarity (Secchi) | 18.9 ft | — |
| Phosphorus | 21.6 µg/L | <30 = clean |
| Trophic State Index | 42 | <50 = clean |
How does Boulder Lake compare?
Boulder Lake's grade of A matches or beats the Wisconsin state average of B. It ranks #156 of 202 lakes in Vilas County by water quality score. Multi-year monitoring data shows water quality is declining based on 3 years of records.