The use of chemical herbicides to control invasive aquatic vegetation in Florida’s Lake Okeechobee is raising questions about potential impacts on drinking water. The lake serves as the primary drinking water source for customers of the Okeechobee Utility Authority, yet herbicides are routinely applied to manage invasive plants. According to a Lake Okeechobee News investigation, several of the herbicides used have restrictions requiring setbacks from drinking water intakes, temporary shutdowns, or water testing to protect water supplies.
The Florida Fish and Wildlife Conservation Commission (FWC) generally maintains a 500-foot buffer around the utility’s primary water intake. However, some herbicide labels specify restrictions extending as far as half a mile (2,640 feet), depending on the chemical and application conditions. Certain herbicides can also persist in water for days or weeks following application, raising additional questions about their potential movement through the aquatic environment.
When questioned about whether herbicides had been applied within these restricted distances, FWC officials stated that contractors follow product label requirements but did not provide the requested application records or distances. Although the investigation did not establish that drinking water had been contaminated, it highlights concerns surrounding chemical aquatic plant management and the importance of protecting water resources. It also underscores the value of considering nonchemical alternatives, such as mechanical harvesting, as part of responsible aquatic vegetation management.