Water Intoxication in Babies: What Parents Need to Know

As parents, it’s natural to wonder when babies can start drinking water. But for babies under 1 year old, especially during the first 6 months, water usually isn’t necessary yet.

According to the CDC’s Morbidity and Mortality Weekly Report on Hyponatremic Seizures in Infants, water intoxication has been linked to cases where babies were given plain water, overly diluted formula, or excessive fluid supplementation.

Because babies are still very small, even a relatively small increase in body water can impact their bodies more quickly compared to older children or adults.

When Can Water Be Introduced?

For the first 6 months, breast milk or formula is enough to keep baby hydrated and nourished.

After 6 months, small amounts of water can be introduced if recommended by your pediatrician, usually around 2–3 oz per day, and offered after milk feeds rather than replacing them.

What Can Cause Water Intoxication in Babies?

Water intoxication may happen when infants:

• Drink plain water in large amounts
• Consume over-diluted formula
• Receive excessive fluid supplementation

Water intoxication can cause serious complications such as: 

• Seizures
• Coma
• Brain damage

Signs Parents Should Watch For

Some symptoms that may indicate fluid imbalance include:

• Drowsiness
• Vomiting
• Irritability
• Unusual tiredness or lethargy

If you notice these signs, it’s best to contact your doctor promptly for medical advice.

The Takeaway

Babies under 1 generally don’t need extra water. Breast milk and formula are designed to provide both hydration and nutrition in the right balance for your little one’s developing body. 

When in doubt, always check with your pediatrician before introducing water regularly to your baby’s routine.