Is Marion Lake Safe for Swimming?
Marion Lake in Dakota County, Minnesota has a water quality grade of A (Excellent). Excellent for swimming, crystal clear water with minimal algae. Water clarity: 7 ft visibility. Phosphorus: 20 µg/L. Chlorophyll-a (algae): 4.6 µg/L. Always check local health department advisories before swimming.
Key Metrics
| Metric | Value |
|---|---|
| Overall Grade | A (Excellent) |
| Water Clarity (Secchi Depth) | 7 ft |
| Phosphorus | 20 μg/L |
| Chlorophyll-a (Algae) | 4.6 μg/L |
| Maximum Depth | 21 ft |
| Location | Dakota County, Minnesota |
How does Marion Lake compare?
With an overall water quality grade of A, Marion Lake matches or beats the Minnesota state average of Grade C. It ranks #1 of 45 lakes in Dakota County by water quality score.
Water clarity (Secchi depth) sits at 7 feet. That puts the lake in good clarity range, with limited algae interference. Algae levels (chlorophyll-a) measure 4.6 µg/L — low and well within safe swimming guidelines.