Of course, use commonsense when it is very hot. And as babies get older & feeding is well established, water may be a good idea.
But indeed, for over 40 years (to my knowledge) the advice has been NOT to give breast fed babies water until feeding is well established.
Bottle fed babies are slightly different but with modern formula would not need water unless it was hot.
Of course, once feeding is established you can be more flexible, and certainly they need water once mixed feeding has begun. I'd also second elegran's advice - but only for an older baby who is feeding well.
So much depends on the age of the baby as a 2 week old has to be treated completely differently from an 8 month!
