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LakeQuality

Green Lake in Green Lake County, Wisconsin has nutrient and algae measurements on record from state and federal monitoring. A water-quality reading is not a swimming clearance. The state water agency and county health departments post current advisories; check them before you swim.. Water clarity: 13.5 ft visibility. Phosphorus: 38.1 µg/L. Chlorophyll-a (algae): 4.4 µg/L. Always check local health department advisories before swimming.

Key Metrics

MetricValue
Water Clarity (Secchi Depth)13.5 ft
Phosphorus38.1 μg/L
Chlorophyll-a (Algae)4.4 μg/L
Maximum Depth236 ft
LocationGreen Lake County, Wisconsin

How does Green Lake compare?

With an overall water-quality readings of , Green Lake matches or beats the Wisconsin state average. It ranks #1 of 7 lakes in Green Lake County by water quality score.

Water clarity (Secchi depth) sits at 13.5 feet. That counts as exceptional clarity — sunlight penetrates deep, supporting submerged plants and limiting algae. Algae levels (chlorophyll-a) measure 4.4 µg/L — low and well within safe swimming guidelines.