At what age can an infant start drinking water and how much is recommend?

When they ask for it: Breast milk or formula are balanced nutrition that provides the proper balance of fluids to nutrients for infants. Water supplements are not necessary. It can be offered, but excess water just means more wet diapers. I find letting grandma or friends offer an ounce or two occasionally lets them participate in infant nurturing, which is socially a good idea. But it is not necessary.