How Clean Is Mason Lake?
Mason Lake does not have enough monitoring data to grade. Its EPA monitoring record does not meet the evidence bar for a letter grade, so it is published unrated — that is an absence of evidence, not a poor result. The measurements below are what the record does contain. Water clarity (Secchi depth): 3 ft. Phosphorus: 21 µg/L. Chlorophyll-a (algae): 16.9 µg/L. Trophic State Index: 56.
Cleanliness Snapshot
| Metric | Mason Lake | Minnesota avg |
|---|---|---|
| Overall Grade | NR | C |
| Water Clarity (Secchi) | 3 ft | — |
| Phosphorus | 21 µg/L | <30 = clean |
| Chlorophyll-a (Algae) | 16.9 µg/L | <10 = clean |
| Trophic State Index | 56 | <50 = clean |
How does Mason Lake compare?
Mason Lake is not rated for water quality — its monitoring record does not meet the evidence bar, so it is not compared with the Minnesota state average. Multi-year monitoring data shows water quality is improving based on 3 years of records.