How Clean Is Mary Lake?
Mary Lake has fair water quality — typical of lakes with moderate nutrient enrichment. It received a water quality grade of C (Fair) based on EPA monitoring data. Water clarity (Secchi depth): 4.1 ft. Phosphorus: 21 µg/L. Trophic State Index: 52.
Cleanliness Snapshot
| Metric | Mary Lake | Minnesota avg |
|---|---|---|
| Overall Grade | C | C |
| Water Clarity (Secchi) | 4.1 ft | — |
| Phosphorus | 21 µg/L | <30 = clean |
| Trophic State Index | 52 | <50 = clean |
How does Mary Lake compare?
Mary Lake's grade of C matches or beats the Minnesota state average of C. It ranks #105 of 120 lakes in Crow Wing County by water quality score. Multi-year monitoring data shows water quality is declining based on 5 years of records.