South Carolina Lake Water Quality

Across South Carolina, 6 lakes carry an active water-quality grade spread over 5 counties. The underlying measurements come from the South Carolina Department of Health and Environmental Control, alongside federal programs and volunteer monitoring networks. Only about 0% of South Carolina's lakes pull an A grade — the smaller, agricultural-watershed lakes that dominate the dataset tend to carry persistent nutrient loads. 17% of lakes fall in the D or F brackets.

Eutrophic conditions dominate — nutrient-loaded, productive, with algal pressure that shows up most years in late summer. These lakes tend to be shallow, agricultural-watershed, and over-warmed by the time July ends. Clarendon ranks highest on average county grade (B). York sits lowest. With only 5 counties in the state, the cross-county spread is narrower than the within-county spread for most lakes.