Adults and children need to hydrate daily. Your body is about two-thirds water, and depending on your body weight, you should probably be drinking roughly half a gallon of water per day.
But babies? That’s a different story.
Breast milk and formula are already about 88 percent water—which means your baby is actually getting all the water it needs from these feedings. It has the perfect ratio of calories and water for hydration, and your baby won’t need anything else.
And experts say that not only is there no need to supplement this with water—in fact, it’s dangerous to do so.
Babies under six months old should not be given any water at all, regardless of climate, unless there is a condition and your pediatrician recommends small amounts of water.
According to pediatrician Dani Stringer, what happens when babies are given water on top of their breast milk or formula intake is water intoxication. When babies under 6 months old are given too much water it dilutes the sodium (salt) in the body, and our bodies need sodium to control blood pressure and our muscles and nerves.
This, in turn, causes the baby’s body to swell, potentially causing brain damage. It’s a reminder to parents to not over-dilute formula as well.
“Remember a baby’s stomach is only about the size of an egg!” she wrote.
After your baby reaches 6 months old, it’s advisable to start introducing small amounts of water. The amount will vary depending on the baby’s body weight, but Stringer approximates about 2 ounces over 24 hour periods until the child’s first birthday.