Georgia Lake Water Quality

32 of the 693 Georgia lakes in this index carry an A–F water-quality grade, spread over 143 counties. Those grades rest on measurements from the Georgia Environmental Protection Division, alongside federal programs and volunteer monitoring networks. The rest are listed for their size, depth and location, without enough recent nutrient or algae sampling behind them to support a letter. A-grade lakes are scarce among the Georgia lakes that carry a letter: about 9% of them. Most sit in C or D, productive, often shallow, frequently algal in late summer.

Lake Hartwell is the largest lake in this index at about 55,950 acres, one of 41 here that clear 500 acres. The rest run smaller, and small and shallow is where nutrient loading shows up first, because there is less water to dilute it and the bottom sediment stays within reach of the sun. Eutrophic conditions dominate the graded set: nutrient-loaded, productive, with algal pressure that shows up most years in late summer. These lakes tend to be shallow, in agricultural watersheds, and over-warmed by the time July ends. The cleanest county on average is Dougherty (grade A); the most-stressed is Cherokee. The gap between the top and bottom counties is large enough that a single figure for Georgia lake water quality hides real local variation.