Washtenaw County Lake Quality
Michigan, 17 lakes, average grade C (Fair)
Washtenaw County's 17 graded lakes fall in the moderate-density bracket for Michigan. The county-level average smooths over real differences — a single agricultural watershed near the southwest corner can pull the average down even if the rest of the county runs clean. The county average is C — the middle of the rubric, with one or two lakes pulling the average up or down depending on year.
The county's lakes lean shallow, which makes the grades sensitive to wind, sediment-resuspension, and any nutrient inputs from the watershed. The cleanest lake on the books is Silver Lake (A); the most-stressed is First Sister Lake (F).
Quick Answers for Washtenaw County
Planning a trip? Check special fishing regulations for Silver Lake, whether the fish are safe to eat, and the best times to fish — or check the official Michigan fishing regulations.
Fishing in Washtenaw County
All Lakes in Washtenaw County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Silver Lake | A | 11.5 ft | - |
| 2 | North Lake North Central Basin; Dexter Township | A | 12 ft | - |
| 3 | Silver Lake | B | 11.5 ft | - |
| 4 | Portage Lake South Basin; Dexter Township | B | 13 ft | - |
| 5 | Little Portage Lake Northeast Basin; Dexter Township | B | 11 ft | - |
| 6 | Base Line Lake | B | 11 ft | - |
| 7 | North Lake | B | 12 ft | - |
| 8 | Little Portage Lake | B | 12 ft | - |
| 9 | Sugarloaf Lake; Lyndon Twp | B | 9.5 ft | - |
| 10 | Pleasant Lake Central Basin; Freedom Township | C | 7.2 ft | - |
| 11 | Pleasant Lake Northwest Basin; Freedom Township | C | 5.8 ft | - |
| 12 | Sugarloaf Lake | C | 9.5 ft | - |
| 13 | Long Lake Southeast Basin; Lyndon Township | C | 9 ft | - |
| 14 | Pleasant Lake | D | 6.3 ft | - |
| 15 | First Sister Lake | F | 3 ft | - |
| 16 | Second Sister Lake | F | 3 ft | - |
| 17 | Ford Lake Central Basin; Ypsilanti Township | F | 3 ft | - |
Other Counties in Michigan
See how Washtenaw County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 15 states.
Where to stay near Washtenaw County
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Source: EPA National Aquatic Resource Surveys, 2026.