Police have received reports of youngsters swimming in Kerrowdhoo Reservoir.
Manx Utilities took to social media to say not only is this illegal, but is a danger to life.
The board says reservoirs are deep and very cold with 'unseen udercurrents' and can have dire consequences for even the strongest of swimmers.
As a result, parents are being urged to speak to their children about the dangers of playing near and in reservoirs.
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