Water and Sewerage Authority officials have issued a warning after blue green algae was discovered in the Clypse Reservoir.
Although algal blooms aren’t always harmful, say some can be toxic and visitors to the reservoir are advised to avoid contact with the water.
Pet owners are also being urged not to allow their animals to drink from it.
Tributes paid to cancer awareness campaigner
Sarah Jarvis has died at the age of 60
Police bail for two people arrested in Ramsey incident
One person was treated for injuries that were described as non-life-threatening
WCAS to extend opening hours next month
It's thanked patrons for their patience during 'very difficult times'
Government support for two 'long-stalled' Douglas developments
Former Newson's building and Duke Street site offered assistance through Island Infrastructure Scheme
Assisted Dying Bill still on track, says mover
Alex Allinson believes UK Ministry of Justice discussions won't slow progress