Grey County Lake Quality
Ontario, 12 lakes, average grade B (Good)
Grey County has 12 graded lakes — a thin enough sample that one or two stressed lakes can move the county average noticeably. Use the per-lake pages below for what actually matters. With an average grade of B, Grey County sits comfortably above the Ontario median.
Most of the county's monitored lakes are shallow — under 50 feet — which means wind keeps the water column mixed all summer and sediment-bound phosphorus releases back into the surface layer whenever the bottom is disturbed. Bass Lake (A) is the cleanest in the county.
Quick Answers for Grey County
Planning a trip? Check special fishing regulations for Bass Lake — or check the official Ontario fishing regulations.
All Lakes in Grey County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Bass Lake | A | 12.5 ft | 5.3 µg/L |
| 2 | Brewster'S Lake | A | 13.8 ft | 9.2 µg/L |
| 3 | Mccullough Lake | A | 13.1 ft | 7.4 µg/L |
| 4 | North Louise Lake | A | 11.5 ft | 9.3 µg/L |
| 5 | Wilder Lake | A | 13 ft | 8.1 µg/L |
| 6 | Mountain Lake | A | 10.8 ft | 11.7 µg/L |
| 7 | Boyd Lake | B | 8.2 ft | 13.4 µg/L |
| 8 | Eugenia Lake | B | 9.8 ft | 8.3 µg/L |
| 9 | Francis Lake | B | 8.2 ft | 9 µg/L |
| 10 | Habermehl Lake | B | 9.5 ft | 11.9 µg/L |
| 11 | Wilcox Lake | B | 10.7 ft | - |
| 12 | Williams Lake | B | 5.6 ft | 4.9 µg/L |
Other Counties in Ontario
See how Grey County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 38 states.
Where to stay near Grey County
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Source: EPA National Aquatic Resource Surveys, 2026.