Seminole County health officials on Friday, June 5, 2026, issued a health alert after tests detected harmful blue‑green algae toxins in Lake Jesup. The advisory tells people not to swim, wade, drink, or otherwise come into contact with the water and urges pet owners and boaters to steer clear while follow‑up testing continues. According to the department, the alert stems from a water sample taken on June 2 and will stay in place until results confirm the lake is safe again.
Health alert and precautions
In a press release from the Florida Department of Health in Seminole County, officials said the alert is tied to the June 2 sample and listed a clear set of precautions: do not drink the water, do not swim or wade, do not use personal watercraft, and avoid any visibly discolored water. The release also stresses that boiling will not remove algal toxins and advises washing skin and clothing with soap and water after any contact. For questions, the release directs residents to DOH‑Seminole's Environmental Public Health Program at 407‑665‑3604.
Where the test results live
The department noted that toxin analyses and statewide notifications are posted on the state's tracking portal and DEP dashboards. The toxin results for Lake Jesup can be viewed on Protecting Florida Together. That portal aggregates sampling from the Department of Environmental Protection and partner agencies and lets residents subscribe for updates. Officials are urging people to check those dashboards before planning any lake activities.
Not an isolated event
Lake Jesup, along with nearby Lake Howell, has cycled through periodic DOH advisories in recent years as warm temperatures and nutrient runoff create ideal conditions for blooms. Local monitoring and archives show multiple past alerts and follow‑up samplings, according to the Seminole County Water Atlas. That track record is a reminder of how quickly a lake's status can flip during the summer.
If you suspect exposure
Residents who think they or their pets may have had contact with the water and then develop symptoms such as nausea, vomiting, or skin irritation are advised to rinse thoroughly and contact a medical provider. The department's release recommends calling the Florida Poison Information Center at 800‑222‑1222 and contacting DOH‑Seminole at 407‑665‑3604 for environmental questions, as outlined in the DOH‑Seminole release. The release also pointedly reminds residents that boiling contaminated water will not eliminate toxins.
Local coverage and next steps
Local outlets have flagged the alert and pointed readers to the DOH and state dashboards for updates; see coverage from WESH and the Florida DOH pages above for the latest information. Agencies will resample the lake and lift the advisory once follow‑up testing shows toxins are no longer detected, officials said. They have promised to update the public as soon as new results are posted.
