When it comes to infant nutrition, parents are flooded with information on what's safe and what's not. However, one piece of advice that often catches new caregivers off guard is the strict guideline against giving babies water, especially during the first six months of life. After all, water is essential for survival — so why exactly is it off-limits for infants?
Pediatricians warn against giving water to babies younger than six months. That’s because doing so can be dangerous. Unlike older children and adults, babies' bodies are not yet equipped to handle extra water, and too much can lead to serious health risks.
The Danger of Water Intoxication
For adults, drinking water is straightforward and safe. Our mature kidneys can efficiently handle plenty of excess water, helping our bodies maintain a careful balance of fluids and electrolytes. Babies, however, have tiny kidneys that aren't yet fully equipped for the same task.
One of the biggest dangers of giving water to an infant is water intoxication, a condition that occurs when too much water dilutes the concentration of sodium in the blood. This can lead to a dangerous electrolyte imbalance called hyponatremia, which causes cells to swell.
When a baby drinks too much water, it can lead to symptoms such as:
Confusion
Drowsiness
Poor coordination
Nausea
Vomiting
Seizures
And in severe cases, water intoxication can lead to coma or death.
Even small amounts of water given regularly can disrupt an infant’s delicate electrolyte balance. That’s why most pediatricians — including the American Academy of Pediatrics (AAP) — recommend exclusively feeding your baby breast milk and/or formula for the first six months.
Read More: What We Can Learn from Babies’ Gut Microbiomes
Breast Milk and Formula Provide Enough Hydration
For those first six months of life, breast milk or formula is all a baby needs. These liquids are specifically formulated to provide exactly the right amount of nutrients and hydration for an infant. Breast milk, for example, is about 87 percent water, and it is perfectly balanced with electrolytes and nutrients that exactly match your baby’s needs. Properly prepared infant formula closely mirrors the composition and water content of breast milk, likewise ensuring all your baby’s nutritional and hydration needs are met.
Introducing additional water to your baby’s diet can result in a lack or imbalance of vital nutrients, affecting their nutritional and immune status. Furthermore, a systematic review of 18 studies found that breast milk or formula alone meets all the hydration needs for infants under six months, even in warmer climates.
Risks of Nutritional Imbalance
Another major risk associated with giving additional water to babies under six months is nutritional imbalance. Babies have very small stomachs, so filling them up with water means they’ll consume less breast milk or formula. Less milk means fewer essential calories and nutrients like proteins, fats, vitamins, and minerals, potentially hindering their growth and development.
Some research has shown that babies frequently given water in the first months of life may not gain adequate weight, putting them at risk for developmental delays and nutritional deficiencies. That’s why skipping water in the early months isn’t just a suggestion — it’s essential for your baby’s healthy development.
When Is Water Safe for Babies?
The consensus from pediatricians worldwide, including the World Health Organization (WHO) and the AAP, is clear: You should not give water to babies younger than six months. After six months, you can introduce small amounts of water as your baby starts solid foods. However, according to the Centers for Disease Control and Prevention (CDC), you should not give a child more than about 4 to 8 ounces of water per day (a few ounces at a time) until their first birthday.
Although parents should not give their babies water before six months of age, after six months, it's crucial to introduce water safely and in moderation. Make sure that water complements rather than replaces breast milk or formula. Infants' first shifting to solid foods can benefit from occasional sips of water, as it helps them learn to drink from a cup, prevents tooth decay (if the water contains fluoride), and generally gets them acquainted with water as a beverage.
In rare cases, such as severe dehydration caused by illness, a healthcare professional might advise very specific electrolyte solutions designed for infants — not just plain water. These specially formulated drinks have the critical balance of electrolytes and hydration your child needs to recover safely.
Keeping Babies Safe and Hydrated
It might seem counterintuitive that something as basic as water could pose a risk to babies, but in the early months of life, even the most essential substances can be harmful if introduced too soon. A baby’s body is uniquely tuned to thrive on breast milk or formula alone. Anything else, even water, can throw off that delicate balance. That’s why understanding the reasoning behind these medical guidelines isn’t just helpful — it’s crucial for protecting your child’s health.
In short, babies can’t have water simply because their bodies aren't ready for it yet. So, by sticking to breast milk or formula during the first six months, you’ll be giving your child exactly what they need to start off life strong.
This article is not offering medical advice and should be used for informational purposes only.
Read More: How the 'First 1,000 Days' Could Shape Your Baby's Future
Article Sources
Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:
Cleveland Clinic. Babies Shouldn’t Drink Water — Here’s Why
Mayo Clinic. Hyponatremia
St. Louis Children's Hospital. Water Intoxication in Infants
Healthychildren.org. How to Safely Prepare Baby Formula With Water
PubMed. Water consumption in 0-6-month-old healthy infants and effective factors: A systematic review
WHO. Breastfeeding
CDC. Information for Families During Infant Formula Shortages
Healthychildren.org. Recommended Drinks for Children Age 5 & Younger
CDC. Community Water Fluoridation Frequently Asked Questions
Nationwide Children's. Dehydration: Giving Liquids at Home
Jake Parks is a freelance writer and editor who specializes in covering science news. He has previously written for Astronomy magazine, Discover Magazine, The Ohio State University, the University of Wisconson-Madison, and more.
