When is it safe to give my baby water?

Breast milk or infant formula provides all the fluids your baby needs during the first year of life—even in hot climates or during the hottest days of the year. If you’re concerned about your baby getting dehydrated on a hot day, don’t be. Breast milk is more than 80 percent water, so it satisfies your baby’s fluid needs even when the temperature rises. 

For healthy babies that are at least 6 months old, it’s safe to offer small sips of water once solid foods have been introduced. Offering water any earlier can put your baby at risk for malnutrition and other health problems.  

Why water can be dangerous to an infant’s health 

Giving water to your baby can put her at risk for malnutrition by causing her stomach to feel full and curbing her appetite for breast milk or infant formula which provide essential nutrients and calories. Remember, water provides neither nutrients or calories.

A baby who drinks too much water can also develop a serious condition known as hyponatremia or “water intoxication.” Hyponatremia occurs when too much water dilutes the level of sodium (salt) in the body, triggering an electrolyte imbalance and causing tissues to swell. This swelling can lead to seizures, comas, brain damage, and even death.

Symptoms of water intoxication in infants include: 

  • irritability or drowsiness 
  • low body temperature 
  • swelling of the face 
  • seizures

Avoid using water to “stretch” formula or breast milk 

A common risk factor for hyponatremia is diluting formula with more water than is recommended, also known as “formula stretching”. The American Academy of Family Physicians cautions caregivers to follow the directions on formula containers exactly–always measure carefully and never add extra water. Using water to dilute formula or breast milk decreases the amount of daily nutrients and calories your baby receives. This practice can have serious health consequences for your baby’s developing brain and increase the risk for learning and behavioral problems.

How to introduce water 

While water is a great thirst quencher for older children, it should never be used as a substitute for breast milk or infant formula. After your baby's first birthday, when she's eating solids and drinking whole milk, she can consume water whenever she likes. If you'd like to introduce water before then, it’s generally safe to offer small sips of water at 6 months of age, but keep these tips in mind:

  • Consult your baby’s health care provider before offering water in case they have specific recommendations based on your baby’s age, weight, and overall health.
  • Do not offer water to babies younger than 6 months of age.
  • Only offer small sips (not ounces), too much water can make her too full to eat or cause a stomach ache.
  • Offer water in a cup not bottle.
  • Forgo water when your baby is sick. Sick babies are at greater risk for dehydration due to vomiting or diarrhea. Breast milk or formula can usually satisfy your baby’s fluid needs but your baby’s health care provider may recommend an electrolyte solution such as Pedialyte.

Anytime you’re concerned that your baby isn’t getting enough fluids (i.e., fewer wet diapers or other signs of dehydration), contact your baby’s health care provider right away.

Last updated November 28, 2017

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