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LakeGrade
A

Black Oak Lake -

Vernon County, Wisconsin

Water Quality Grade: AExcellent

Crystal clear — you can see 88.6 feet down. Phosphorus level: 10.2 µg/L.

MetricValueGrade
Water Clarity (Secchi Depth)27 mA
Phosphorus10.2 µg/LA
Chlorophyll-a (Algae)No data

County Ranking

Ranked #69 of 245 lakes in Vernon County

Data Sources

Data from the EPA Water Quality Portal

Grading methodology based on Metropolitan Council standards

Most recent sample: 2025-08-21

Monitoring stations: 1