The public has been urged to stay safe and not take risks around rivers, reservoirs and lochs this summer.
The warning from Scottish Water came a day after an Edinburgh kayaker drowned after falling into a Perthshire loch.
The 50-year-old man was pulled from Loch Tummel following a major rescue operation on Sunday afternoon.
It also follows the deaths of three people in three years at Prestonhill Quarry in Inverkeithing.
Scottish Water said children and parents should take particular care during the summer holidays and any spells of warm weather.
New figures from the National Water Safety Forum show that last year 255 people died due to unintentional drowning in the UK, including 46 in Scotland.
Peter Farrer, Scottish Water’s chief operating officer, said: “Safety is a serious issue as, while the water may look harmless, there are many hidden dangers.
“We need to ensure children and parents are aware of these hazards.
“We are reminding parents to keep their children safe and asking adults to act responsibly around water courses.”
Hazards at reservoirs include dams, steep banks, overflows, deep cold water and underwater pipe work.
They are usually in remote locations, meaning there is no immediate assistance and mobile reception can be poor.
Carlene McAvoy, community safety development officer for RoSPA Scotland said: “One of the main dangers of open water is cold water shock, when the low temperature of water will affect the body’s normal functions and lead to someone getting into trouble.
“It can even affect the most confident swimmers.
“It’s important to remember that even if it’s a hot day, the water can still be cold – it only needs to be 15 degrees or lower for cold water shock to kick in.”
Scottish Water’s advice is also targeted at pet owners.
Dogs should be kept on a lead if being walked beside bodies of open water.
Often pets survive falling into water while owners who dive in to save them often do not.
In 2014, 18-year-old Cameron Lancaster drowned at Prestonhill Quarry while taking part in the “ice bucket challenge”.
His mother Gillian Barclay has since launched a campaign for the quarry to be drained and has called for a fatal accident into his death, as well as the deaths of John McKay, 18, from Kirkcaldy, and teacher Kelda Henderson, 36, from Edinburgh.