Essex County Lake Quality

Essex County in Massachusetts carries 57 monitored lakes — one of the lake-richer counties in our dataset. Coverage that dense usually reflects active lake-association sampling alongside state-agency monitoring. 6 of those lakes carry recent nutrient and algae readings. The county-level summary describes that subset, not every water body listed. The county's readings sit in the middle of the Massachusetts range, with one or two lakes pulling the average up or down depending on year.

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. Walden Pond has the lowest nutrient and algae readings in the county.