Snohomish County Lake Quality

Snohomish County in Washington carries 52 monitored lakes — one of the lake-richer counties in our dataset. Coverage that dense usually reflects active lake-association sampling alongside state-agency monitoring. 1 of those lake carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. For Snohomish County the spread behind the average matters more than the average itself: a few nutrient-rich lakes among many clear ones produce the same figure as the inverse.

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. Weallup Lake has the lowest nutrient and algae readings in the county.