Firefighters are urging children not to swim in lakes and reservoirs during the school summer holidays in a bid to save lives.
South Yorkshire Fire and Rescue has dealt with 49 incidents since 2012 where people needed rescued from open water.
Three people drowned during that period.
Fire chiefs said open water should be avoided because river flows can be unpredictable and water is often deeper, colder and faster than expected.
Head of community safety, Trevor Bernard, said: “We regularly receive 999 calls in the summer about children and young people getting into difficulty in water, so it’s only a matter of time before someone’s safety is really put at risk unless people listen to our advice.
“It can be tempting to cool off in the summer months, but stick to a swimming pool. Hundreds of people drown each year in the UK and places like rivers, lakes or flooded quarries are completely unsuitable for swimming as they hide a number of hidden dangers.
Over 400 people die in the water every year in the UK.
"The dangers of open water are that it can be much deeper than you expect and rivers, lakes, canals and reservoirs are much colder than you think.
"Open water can carry water borne diseases, like Weils disease, cold water dramatically affects your ability to swim and there may be hidden currents, which can pull you under the water.
"You don’t know what lies beneath, like pieces of rubbish or reeds. which can trap or injure you."