I've tried to find the source of that "8 glasses" recommendation. The general consensus guess is that it stemmed from a National Resource Council recommendation in about 1945, that adults should drink 1 ml/calorie of food, about 2 - 2.5 liters a day. Some water purveyors have been promoters of the idea. Otherwise this myth has been busted over and over. Solid food provides quite a bit of water in our diet. Water fluoridation varies a lot, geographically. https://www.cdc.gov/fluoridation/statistics/2018stats.htm
I was born and spent my first years in Colorado before fluoridation was a thing and still have all my teeth and they are quite hard, which my dentists have all attributed to natural fluoridation. People like me inspired the water program, sorry, but I think putting it in toothpaste was a worse mistake. If people don't swallow some then they spit it out and eventually it adds to the environment.
I've tried to find the source of that "8 glasses" recommendation. The general consensus guess is that it stemmed from a National Resource Council recommendation in about 1945, that adults should drink 1 ml/calorie of food, about 2 - 2.5 liters a day. Some water purveyors have been promoters of the idea. Otherwise this myth has been busted over and over. Solid food provides quite a bit of water in our diet. Water fluoridation varies a lot, geographically. https://www.cdc.gov/fluoridation/statistics/2018stats.htm I was born and spent my first years in Colorado before fluoridation was a thing and still have all my teeth and they are quite hard, which my dentists have all attributed to natural fluoridation. People like me inspired the water program, sorry, but I think putting it in toothpaste was a worse mistake. If people don't swallow some then they spit it out and eventually it adds to the environment.