Babies should drink only breast milk or formula not water  until they reach 6 months of age, according to the American Academy of Pediatrics (AAP) and Children’s Health of Orange County (CHOC). This is because babies in the first six months after birth do not need water in addition to formula or breast milk, which provides all of the hydration and nutrients babies need, unless specifically advised by a pediatrician.

“Breast milk is made up of 80-90% water, which is why you don’t need to add water when breastfeeding,” Jasmine Pendergrass, M.D., pediatric chief resident at the Baylor College of Medicine, told VERIFY.

At the six-month mark, babies can be introduced to water in an open, sippy cup, or strawed cup, the AAP says on its website. Babies only need about 4-8 ounces of water per day until they reach 1 year old because the rest of their liquid intake is still coming from breast milk or formula.