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LakeQuality

Forest Lake in Washington County, Minnesota has nutrient and algae measurements on record from state and federal monitoring. Chlorophyll-a in the monitoring record runs high enough that algae is a factor. 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: 5.1 ft visibility. Phosphorus: 28 µg/L. Chlorophyll-a (algae): 16.5 µg/L. Always check local health department advisories before swimming.

Key Metrics

MetricValue
Water Clarity (Secchi Depth)5.1 ft
Phosphorus28 μg/L
Chlorophyll-a (Algae)16.5 μg/L
Maximum Depth37 ft
LocationWashington County, Minnesota

How does Forest Lake compare?

With an overall water-quality readings of , Forest Lake runs above the Minnesota state average. It ranks #54 of 75 lakes in Washington County by water quality score.

Water clarity (Secchi depth) sits at 5.1 feet. That falls into moderate clarity — typical for lakes with some nutrient enrichment. Algae levels (chlorophyll-a) measure 16.5 µg/L — moderate; acceptable for swimming on most days, but worth checking advisories.