Skip to main content
LakeQuality

Minnetonka Lake reads lower on nutrients and algae than Sarah Lake. Both are in Hennepin County, Minnesota.

Reviewed by LakeQuality Editorial Team · Updated

Both Minnetonka Lake and Sarah Lake sit in Minnesota. A same-state comparison strips out the state-level water-quality regime as a variable: any differences in the readings here are about the lakes themselves, not the agencies sampling them. Minnetonka Lake reads materially cleaner than Sarah Lake on nutrients and algae. A gap that wide is unlikely to close in a single year of remediation work; it reflects multi-decade differences in the lakes themselves.

For a recreational visitor, the wider gap in the readings is decisive: Minnetonka Lake has the lower nutrient and algae numbers. For a researcher, the gap is the interesting part: what is different about the two watersheds, and which of those differences is mutable?

Minnetonka Lake

Hennepin County, Minnesota

Good clarity, visible to about 10 ft.

Sarah Lake

Hennepin County, Minnesota

Very murky, less than 3.1 ft of visibility.

Side-by-Side Metrics

MetricMinnetonka LakeSarah Lake
Water Clarity10 ft Better3.1 ft
Phosphorus28 µg/L Better106.1 µg/L
Chlorophyll-a (Algae)10.1 µg/L Better34.3 µg/L
Maximum Depth113 ft Better59 ft
Surface Area14,206 acres557 acres
Public AccessYesYes
Fish Species18 Better13
Trophic Statemesotrophiceutrophic

A green ✓ marks the better value for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better). Surface area and trophic state carry no tick — a bigger lake is not a better lake.

Verdict

Minnetonka Lake reads lower on nutrients and algae than Sarah Lake. Water clarity: 10 ft vs 3.1 ft. For fishing diversity, Minnetonka Lake also leads with 18 species.

Source: EPA National Aquatic Resource Surveys, 2026.