Snohomish County Lake Quality
Washington, 8 lakes, average grade C (Fair)
Snohomish County has 8 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. 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 Nla Lake (A); the most-stressed is Lake Beecher (D).
Quick Answers for Snohomish County
Planning a trip? Check special fishing regulations for Nla Lake — or check the official Washington fishing regulations.
All Lakes in Snohomish County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Nla Lake | A | 22.6 ft | 13.5 µg/L |
| 2 | Lake Roesiger | A | 17.1 ft | - |
| 3 | Stickney Lake | B | 11.8 ft | - |
| 4 | Nla Lake | C | 13.8 ft | 9000 µg/L |
| 5 | Ross Lake | C | - | 46 µg/L |
| 6 | Weallup Lake | C | - | 40 µg/L |
| 7 | Lake Beecher | D | 5.6 ft | - |
| 8 | Jsl Lake | D | - | 64 µg/L |
Other Counties in Washington
See how Snohomish County stacks up in the national county water-quality rankings, or browse the full directory of graded lakes across all 34 states.
Where to stay near Snohomish County
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Source: EPA National Aquatic Resource Surveys, 2026.