Drinking eight glasses a day does not make you healthier - it just makes you need the loo more
Drinking eight glasses of water is touted as bringing unbelievable benefits such as making you look younger, have plumper skin and feel healthier.
But the reason why these claims often seem to good to be true, is because they are.
Academics have found no evidence that drinking vast quantities of water improves your health.
And now one health researcher is so fed up with the myth being cited as fact that he has written an article begging people to stop repeating the advice.
In an article for The New York Times, Aaron E. Carroll, Professor of Paediatrics and Assistant Dean for Research Mentoring at Indiana University School of Medicine, writes: "If there is one health myth that will not die, it is this: You should drink eight glasses of water a day.
"It's just not true.
"There is no science behind it."
He says the original advice was people needed the equivalent of eight glasses of water a day.
However, scientists included the amount of fluid ingested through other food and vegetables, and never intended for people to drink eight glasses of water on top of their daily food and drink.
"Many people believe that the source of this myth was a 1945 Food and Nutrition Board recommendation that said people need about 2.5 litres of water a day.
"But they ignored the sentence closely behind.
It read: "Most of this quantity is contained in prepared foods."
Mr Carroll said there was little evidence drinking extra water had any health benefits at all and condemned claims that people risked ill health from not drinking enough.
He said: "These reports work up a fear that otherwise healthy adults and children are walking around dehydrated, even that dehydration has reached epidemic proportions.
"You don't have to consume all the water you need through drinks.
"You also don't need to worry so much about never feeling thirsty.
"The human body is finely tuned to signal you to drink long before you are actually dehydrated."