The South Carolina Department of Environmental Services (SCDES) has released the most recent Harmful Algal Bloom (HAB) update for Lake Hartwell, based on sampling performed on June 16, 2025. This bi-weekly report reflects continued improvement across many coves and shoreline areas, with several locations now cleared from the Recreational Watch list.
During the June 16 survey, SCDES’s Aquatic Science Division (ASD) collected water samples from six lake locations. While blue-green algae (cyanobacteria) are still present, toxin levels remain below the state’s recreational safety threshold of 8 micrograms per liter for microcystin. The latest data allowed SCDES to lift the Recreational Watch in the following areas:
- Six and Twenty Creek lake arm (between SC-24 and Centerville Road)
- Lower Lake Hartwell (Sadlers Creek State Park to Hartwell Dam)
- Martin Creek and Coneross Creek lake arms (south of Cherry Creek Road to Camp Creek Road)
The Recreational Watch remains in effect for portions of the Tugaloo and Seneca River lake arms. As always, SCDES recommends avoiding contact with the water and keeping pets out of the lake in areas where algal blooms are observed.
SCDES also reminds boaters and lake users to “clean, drain, and dry” their boats and equipment after use. Even though the types of algae found in Lake Hartwell and nearby Broadway Lake are naturally occurring, algae can survive out of water for extended periods and should not be transferred between water bodies.
Download the full June 20, 2025 HAB Report (PDF)
Click here to view or download
We’ll continue sharing these updates to help the Lake Hartwell community stay safe and informed.
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