Warnings have been issued to know the dangers of swimming in open waters and reservoirs.
Police officers recently had cause to speak a group of young people who were swimming in a Dewsbury reservoir.
A spokesperson for the Dewsbury Neighbourhood Policing Team said: "Reservoirs are dangerous places for children to swim in.
"There are underwater chambers where children could get sucked into and would be unable to get out.
"Please, please speak with your young people and advise them not to swim in reservoirs and how dangerous it is."
Yorkshire Water is calling for people throughout the region to stay safe at its 120 reservoirs.
The plea comes in a bid to stop tragic incidents at its reservoirs.
Alastair Harvey, Yorkshire Water’s Recreation Advisor, said: “Reservoirs are deep and the water in them doesn’t flow or heat up in the same way as rivers or the sea with the temperature rarely rising above 12C.
"People sometimes do not understand how dangerous they can be. Just a short swim can result in a tragic loss of life and we want to once again ask people to stay out of our reservoirs.”