Is Lake Jesup safe? Toxic algae status
Seminole County, Florida. Harmful algal bloom (blue-green algae) reports from the Florida Department of Environmental Protection (DEP).
Data checked 24 October 2026. Florida data is published as a yearly file; current sampling is shown on the DEP dashboard.
100
sampling visits since 2020
39
visits where a bloom was seen
0.79 µg/L
highest microcystin result
Year by year
Each box shows visits where a bloom was seen, out of all sampling visits that year.
Reports at Lake Jesup are most often logged in April, May and October.
Recent reports
| Date | Location | Result |
|---|---|---|
| 16 December 2025 | Lake Jesup - Center (OW-CTR) | No bloom seen · microcystin not detected |
| 18 November 2025 | Lake Jesup - Center (OW-CTR) | Bloom seen · microcystin not detected |
| 21 October 2025 | Lake Jesup - Center (OW-CTR) | Bloom seen · microcystin not detected |
| 7 October 2025 | Lake Jesup - Center (OW-CTR) | Bloom seen · microcystin not detected |
| 16 September 2025 | Lake Jesup - Center (OW-CTR) | No bloom seen · microcystin not detected |
| 2 September 2025 | Lake Jesup - Center (OW-CTR) | No bloom seen · microcystin not detected |
| 18 August 2025 | Lake Jesup - Center (OW-CTR) | No bloom seen · microcystin not detected |
| 5 August 2025 | Lake Jesup - Center (OW-CTR) | Bloom seen · microcystin not detected |
| 22 July 2025 | Lake Jesup - Center (OW-CTR) | Bloom seen · microcystin not detected |
| 10 July 2025 | Lake Jesup - Center (OW-CTR) | No bloom seen · microcystin not detected |
| 26 June 2025 | Lake Jesup - Center (OW-CTR) | No bloom seen · microcystin not detected |
| 10 June 2025 | Lake Jesup - Center (OW-CTR) | No bloom seen · microcystin not detected |
What the results mean
Staff saw a bloom at the sampling site. A sample may then be tested for toxins.
Microcystin, a liver toxin made by blue-green algae, was found in the sample.
At or above the level where the US EPA recommends swimming advisories for microcystins.
Dogs and toxic algae
Dogs face the greatest risk because they swallow water and lick algae off their fur. If a bloom has been reported, keep dogs out of the water and away from scum on the shore. If your dog swims in water that might have algae, rinse it with clean water straight away and call a vet if it seems unwell.
Common questions
Is Lake Jesup safe to swim in?
The most recent entry in Florida's published data is from 16 December 2025: no bloom seen · microcystin not detected (Lake Jesup - Center (OW-CTR)). Blooms have been recorded at Lake Jesup in 6 different years, so treat green, scummy or discoloured water with caution. For current conditions, check the DEP Algal Bloom Dashboard and posted signs.
When does Lake Jesup get algae blooms?
In the state's records, reports are most often logged in April, May and October. Blooms are most likely in warm, calm weather, but they can appear at other times of year.
Source: Florida Department of Environmental Protection (DEP), official data. This page is independent and not affiliated with the State of Florida.