Babies That Are Under Six Months Old Should Never Drink Water

It seems like common sense—when thirsty, drink water. Adults rely on it to stay hydrated, and even toddlers are encouraged to sip throughout the day. But what if the same logic could put a baby’s life at risk?

Unlike older children and adults, infants under six months have entirely different hydration needs. Their bodies are still developing, their kidneys are immature, and their tiny stomachs are designed to process only nutrient-rich breast milk or properly prepared formula. Giving a young baby water may seem harmless, but it can have dangerous consequences—diluting sodium levels in their blood, interfering with nutrient absorption, and even leading to life-threatening complications like water intoxication. What’s safe for us isn’t always safe for them, and in this case, the difference could be life or death.

But what makes water so risky for babies this young? And why do experts, including pediatricians and medical researchers, strongly warn against it? The answer goes beyond hydration and reveals something far more concerning.

Why Newborns and Infants Under Six Months Should Avoid Water

For healthy adults, drinking water is second nature—we rely on it to stay hydrated and keep our bodies functioning properly. But when it comes to infants, the same rules don’t apply. For adults, drinking pure water is essential for staying hydrated and maintaining overall balance in the body. It’s a daily necessity, often recommended in multiple glasses. However, for babies under one year old—especially in the first nine months—consuming too much water can pose serious health risks. Unlike older children and adults, babies have an extremely delicate balance of fluids and nutrients that can be easily disrupted by even a small amount of water.

A newborn’s stomach is incredibly small, holding just 1 to 2 teaspoons (5 to 10 milliliters) of liquid at birth. Every drop that enters their tiny system needs to be packed with essential nutrients, calories, and antibodies—all of which come from breast milk or properly prepared formula. Water, on the other hand, provides no nutritional value. If an infant’s stomach is filled with water instead of nutrient-rich milk, they risk missing out on critical nourishment necessary for proper growth, brain development, and immune support.

Breast milk and formula are perfectly designed to meet an infant’s hydration needs during their first six months. There is no need for extra water, even in hot weather. Breast milk or formula provides all the fluid healthy babies need. Unlike water, breast milk contains the perfect balance of hydration, electrolytes, and nutrients to sustain a baby’s health.

Some parents may worry that their baby still seems thirsty after feeding, especially in warm climates. While it may seem logical to offer a little water, experts caution against it. If a parent believes their baby needs extra water, the amount should be restricted to two to three ounces per serving and only given after the infant has already had enough breast milk or formula to meet their nutritional needs. This ensures that the baby is getting the nutrients they need before any additional fluids.

At this stage, a baby’s kidneys are still immature and cannot process excess water effectively. Even small amounts of extra water can dilute sodium levels in the bloodstream, leading to dangerous complications. Excess water can lower a baby’s sodium levels to dangerous levels, potentially resulting in seizures, coma, brain damage, or even death. This is why pediatricians strongly recommend avoiding water altogether for infants under six months old. 

The safest and healthiest choice for a young baby is exclusive breastfeeding or properly mixed formula feeding. Parents who are concerned about hydration should always consult a pediatrician rather than introducing water, as even a small amount can interfere with their baby’s nutritional needs. James P. Keating, MD, a retired medical director of the St. Louis Children’s Hospital Diagnostic Center, also reiterated that parents should avoid letting their infants participate in swimming lessons, stating, “Repeated dunking of infants can cause them to gulp water and has caused seizures in the infants at the poolside.”

Understanding Water Intoxication in Infants

Water intoxication, though uncommon, poses a significant risk to infants under six months old due to their developing kidneys and small body size. Their kidneys are not yet mature enough to excrete excess water efficiently, making it easier for water to accumulate and dilute essential electrolytes. This can result in severe hyponatremia, a condition where sodium levels drop dangerously low, leading to swelling in the brain and other tissues, potentially causing seizures, coma, and even death​.

A case study published in Cureus highlighted a five-month-old girl who developed status epilepticus, a life-threatening seizure condition, after consuming excessive water. The infant was given 100 mL of water every three hours in between formula feedings, which led to severe hyponatremia (108.5 mmol/L, normal range: 135-145 mmol/L). She presented at the hospital with facial puffiness, cyanosis, and seizures that lasted for 25 minutes. Lab tests confirmed dangerously low sodium levels, requiring emergency intervention with hypertonic saline and anticonvulsant medication​.

Recognizing the signs of water intoxication is crucial for timely intervention. Symptoms may include drowsiness, irritability, low body temperature (hypothermia), facial puffiness, and, in severe cases, seizures. Since hyponatremia is a leading cause of new-onset non-febrile seizures in infants, it is critical to rule out water intoxication in any case of unexplained convulsions​.

The key to prevention is educating parents and caregivers on proper infant hydration. Excessive water intake, whether from over-diluted formula or unnecessary supplemental water, can have devastating effects. This case reinforces the importance of following recommended feeding practices and ensuring that infants receive only breast milk or properly prepared formula to meet their hydration and nutritional needs

When Can Babies Safely Drink Water and How to Ensure Proper Hydration?

While water is essential for older children and adults, infants under six months should not consume it. Their bodies are not equipped to handle additional fluids beyond breast milk or properly prepared formula. However, as babies grow and their digestive and renal systems mature, small amounts of water can be introduced safely at the appropriate time.

When Is It Safe to Give Babies Water?

Experts, including the World Health Organization (WHO), recommend that infants should only be introduced to small amounts of water after six months of age. At this stage, babies typically begin consuming solid foods, which naturally increase their need for additional fluids. Even then, water should only be given in small sips, and breast milk or formula should remain their primary source of nutrition and hydration until at least one year old.

For babies between six and twelve months, the recommended daily intake of water is no more than 4 to 8 ounces per day, offered in small sips. This should never replace breast milk or formula, which still provides essential nutrients and hydration. Pediatricians caution that even after six months, excessive water intake can still pose risks, particularly if it displaces calorie-dense milk feedings.

Safe Hydration Practices for Babies

To ensure proper hydration while preventing the risks associated with early or excessive water intake, parents should follow evidence-based guidelines that prioritize infant health. Here are some of the following safe hydration practices for babies:

• Exclusive Breastfeeding or Formula Feeding Before Six Months: Infants receive all the hydration they need from breast milk or properly mixed formula. Additional water is unnecessary and can be harmful.
• Introducing Water Gradually After Six Months: When a baby is developmentally ready for solid foods, water can be offered in small sips. Pediatricians recommend limiting intake to a few ounces per day.
• Avoid Diluting Formula: Some parents mistakenly add extra water to formula, thinking it will stretch the supply or help with digestion. This practice can lead to dangerous hyponatremia, as seen in medical case studies of water intoxication in infants​. Formula should always be prepared according to the manufacturer’s instructions.
• Monitoring for Signs of Dehydration: If an infant seems thirsty or is experiencing signs of dehydration—such as fewer wet diapers, dry lips, or excessive fussiness—it is best to increase breast milk or formula feedings rather than offer water.
• Handling Hot Weather and Illnesses Safely: Parents may worry that their baby needs extra fluids during hot weather or illness. In these cases, offering more frequent breast milk or formula feedings is the safest way to maintain hydration.

By following these recommendations, caregivers can ensure that their infants remain properly hydrated while avoiding the risks associated with premature or excessive water intake. The key is to introduce water at the right time and in the right amount, ensuring that it supports a baby’s development rather than interfering with essential nutrition.

Protecting Your Baby: The Life-Threatening Risk of Giving Water Too Soon

What seems harmless could be deadly. A few extra sips of water might be all it takes to put a baby in danger. Medical experts worldwide warn that giving water to infants under six months can lead to seizures, brain damage, and even death due to electrolyte imbalances and water intoxication​.

This isn’t just a caution—it’s a matter of life and death. Case studies have shown that even well-meaning parents have unintentionally put their babies at risk by offering water too early​. The safest choice? Follow medical advice, trust science, and keep water off the menu until the right time. When it comes to your baby’s health, waiting isn’t just a recommendation—it’s a necessity.

No tradition, myth, or outdated advice is worth gambling with an infant’s safety. Medical research has advanced, and the facts are clear—water before six months is dangerous. Parents and caregivers must stand by evidence-based guidance and ensure their baby receives the nutrition and hydration they truly need. A small mistake could have devastating consequences, but the right knowledge can save lives.