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Minnewashta Lake reads lower on nutrients and algae than Minnetonka Lake. Both are in Minnesota.

Reviewed by LakeQuality Editorial Team · Updated

Minnetonka Lake and Minnewashta Lake are both in Minnesota — a same-state head-to-head where the comparison comes down to lake-specific differences in depth, watershed, and monitoring history rather than the broader state-level water-quality regime. The readings are meaningfully apart: Minnewashta Lake carries clearly lower phosphorus and chlorophyll-a readings than Minnetonka Lake. A spread that wide reflects real underlying differences, in watershed inputs, depth profiles, or monitoring rigor.

For a recreational visitor, the wider gap in the readings is decisive: Minnewashta 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.

Minnewashta Lake

Carver County, Minnesota

Good clarity, visible to about 11.5 ft.

Side-by-Side Metrics

MetricMinnetonka LakeMinnewashta Lake
Water Clarity10 ft11.5 ft Better
Phosphorus28 µg/L14 µg/L Better
Chlorophyll-a (Algae)10.1 µg/L2.3 µg/L Better
Maximum Depth113 ft Better70 ft
Surface Area14,206 acres680 acres
Public AccessYesYes
Fish Species18 Better14
Trophic Statemesotrophicmesotrophic

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

Minnewashta Lake reads lower on nutrients and algae than Minnetonka Lake. Water clarity: 11.5 ft vs 10 ft. For more fish-species variety, Minnetonka Lake edges ahead with 18 documented species.

Source: EPA National Aquatic Resource Surveys, 2026.