Whatcom County Lake Quality
Washington, 4 lakes, average grade B (Good)
Only 4 lakes in Whatcom County carry an active grade. The county-level summary is therefore representative of those specific lakes, not necessarily of every water body in the county. With an average grade of B, Whatcom County sits comfortably above the {{stateName}} 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. Ross Lake (A) is the cleanest in the county.
Quick Answers for Whatcom County
Planning a trip? Check special fishing regulations for Ross Lake — or check the official Washington fishing regulations.
All Lakes in Whatcom County
| Rank | Lake | Grade | Clarity | Phosphorus |
|---|---|---|---|---|
| 1 | Ross Lake | A | 18.8 ft | 4.5 µg/L |
| 2 | Nla Lake | B | 16.4 ft | 7502.8 µg/L |
| 3 | Nla Lake | C | 10.2 ft | 7508 µg/L |
| 4 | Nla Lake | C | - | 8000 µg/L |
Other Counties in Washington
See how Whatcom 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 Whatcom County
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Source: EPA National Aquatic Resource Surveys, 2026.