What is the water clarity of Clear Lake?

Clear Lake has a Secchi depth (water clarity) of 2.5 feet. That is poor clarity, indicating heavy algae or sediment.

Does Clear Lake have an algae problem?

Clear Lake has a chlorophyll-a (algae) level of 59.3 µg/L. That is high — the lake is at meaningful risk of harmful algal bloom advisories in summer.

How Clean Is Clear Lake?

Q: Is Clear Lake polluted?

Clear Lake shows pollution indicators consistent with nutrient over-enrichment (typically phosphorus from agricultural runoff, fertilizer, or failing septic systems). Its has a water quality grade of F (Algae-prone), reflecting elevated nutrient and algae levels.

Clear Lake is algae-prone, with a higher bloom risk in warm months. It received a water quality grade of F (Algae-prone) based on EPA monitoring data. Water clarity (Secchi depth): 2.5 ft. Phosphorus: 151 µg/L. Chlorophyll-a (algae): 59.3 µg/L. Trophic State Index: 70.

Cleanliness Snapshot

Metric	Clear Lake	Minnesota avg
Overall Grade	F	C
Water Clarity (Secchi)	2.5 ft	—
Phosphorus	151 µg/L	<30 = clean
Chlorophyll-a (Algae)	59.3 µg/L	<10 = clean
Trophic State Index	70	<50 = clean

How does Clear Lake compare?

Clear Lake's grade of F falls below the Minnesota state average of C. It ranks #2 of 2 lakes in Waseca County by water quality score. Multi-year monitoring data shows water quality is declining based on 5 years of records.

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More on Clear Lake

Is Clear Lake safe for swimming? →What fish are in Clear Lake? →Is Clear Lake polluted? →When Does Clear Lake Freeze? Typical Ice-In Dec 1, Ice-Out Apr 2 →Full water quality report →Waseca County lakes →Cleanest lakes in Waseca County →Cleanest lakes in Minnesota →