A
Union Lake
Polk County, Minnesota
Water Quality Grade: A — Excellent
Good clarity — visible to about 14.5 feet. Phosphorus level: 14 µg/L.
| Metric | Value | Grade |
|---|---|---|
| Water Clarity (Secchi Depth) | 4.42 m | B |
| Phosphorus | 14 µg/L | A |
| Chlorophyll-a (Algae) | No data |
County Ranking
Ranked #1 of 22 lakes in Polk County
Data Sources
Data from the EPA Water Quality Portal
Grading methodology based on Metropolitan Council standards
Most recent sample: 2024-09-24
Monitoring stations: 2