As the bank holiday approaches and families are heading to reservoirs like Linacre in the Chesterfield area, there are warnings not to go for a dip.
Severn Trent Water are warning people to stay safe and not to be tempted to go swimming.
The Linacre reservoirs in the Chesterfield area of Derbyshire are a popular tourist attraction, but this year has seen a worrying trend in people risking their lives to take a swim during the summer months.
Andrew Parsons, public assess sites manager for Severn Trent, said:
"Reservoirs are much more dangerous than swimming in a normal pond or lake because the reservoir gets very deep, very quickly, and the temperature of the water rarely rises above eight degrees Celsius, even in the summer months. That's cold enough to cause hypothermia, so no matter how strong a swimmer you are, the cold will make the muscles start to cramp quickly, which means serious chance of swimmers drowning."
More from Local