Whatcom County Lake Quality

There are 34 monitored lakes in Whatcom County. The mix is varied enough that the county-level average tells you the broad strokes, not the choose-this-cabin specifics. 1 of those lake carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county-wide average lands at B — solid water quality with most lakes carrying clear summer transparency and low-to-moderate phosphorus.

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 Ross Lake (B); the most-stressed is Ross Lake (B).