Minnetonka Lake vs Sarah Lake
Water quality, depth, fish species, and recreation comparison.
Minnetonka Lake has a higher water quality grade (C, Fair) than Sarah Lake (F, Very Poor). Both are in Hennepin County, Minnesota.
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 grade differences here are about the lakes themselves, not the agencies grading them. Minnetonka Lake (C) is materially cleaner than Sarah Lake (F). 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 grade gap is decisive — Minnetonka Lake is the better water-quality choice. 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
Good clarity, visible to about 10 ft.
Sarah Lake
Very murky, less than 3.1 ft of visibility.
Side-by-Side Metrics
| Metric | Minnetonka Lake | Sarah Lake |
|---|---|---|
| Overall Grade | C (Fair) | F (Very Poor) |
| Water Clarity | 10 ft | 3.1 ft |
| Phosphorus | 28 µg/L | 106.1 µg/L |
| Chlorophyll-a (Algae) | 10.1 µg/L | 34.3 µg/L |
| Maximum Depth | 113 ft | 59 ft |
| Surface Area | 14,206 acres | 557 acres |
| Public Access | Yes | Yes |
| Fish Species | 18 | 13 |
| Trophic State | mesotrophic | eutrophic |
Bold value = better for that metric (lower phosphorus / chlorophyll = cleaner; higher Secchi / depth / species count = better).
Verdict
Minnetonka Lake wins on overall water quality with a Grade C versus Sarah Lake's Grade F. 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.