Clackamas County Lake Quality

Clackamas County holds 10 monitored lakes. With a sample that small the county-level summary describes those specific waters, not necessarily every water body in the county. 1 of those lake carry an A–F grade. The county-level summary describes that subset, not every water body listed. The county's average grade is A — among the cleanest in Oregon. 1 lakes pull an A on their own, and almost none fall into the D or F brackets.

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 Timothy Lake (A); the most-stressed is Timothy Lake (A).