a baby drinking from a coconut

Do babies need water?

Do babies need water?

This is a question most parents will find themselves asking sooner or later, especially on a really hot day. There may also be a lot of people out there with a lot of misinformation who may believe that babies do need additional water, as they may find it hard to believe that breastmilk or formula is sufficient. But despite all the different opinions out there, most research and medical professionals will all agree that water should not be given to a baby under the age of 6 months of age. Water is completely optional for breastfed babies until 12 months of age. Breastmilk and formula offer all the needed hydration a baby needs.

Why shouldn’t babies drink water under 6 months?

Both breastmilk and formula offer more than enough water to meet an infant’s needs. In fact, breastmilk is 87.5% water. Not only do infants under 6 months not need water, but water can actually be incredibly dangerous to them. It can cause them to lose out on very important calories and nutrients, electrolyte imbalance and water intoxication and even hyponatremia. Giving water to a baby under the age of 6 months can be life threatening.

Displaced nutrition

The more an infant’s small stomach is filled with water, which is empty in calories and nutrients, the less breastmilk and formula they will drink. Breastmilk and formula offer all the needed nutrients to an infant in the first 6 moths of life. So, when they don’t receive enough milk, they also don’t receive enough calories and nutrients. This can cause a faltering in both their growth and development.

Water intoxication

Infants also have very underdeveloped kidneys, like most of their organs. This means their kidneys cannot yet handle and filter water like it should. When infants drink water, it can very quickly cause water intoxication, also known as water poisoning and overhydration. Water intoxication happens when a person drinks more water than their kidneys can handle which then causes an excess of water in the bloodstream. This causes an electrolyte imbalance. When this happens, it causes a potentially fatal disturbance in brain function and swelling of the brain.


When the electrolyte imbalance causes very low sodium levels, doctors refer to it as hyponatremia. This is extremely dangerous and can be life threatening. Hyponatremia can cause overactive reflexes, loss of consciousness, seizures, coma and in the most severe cases, death.

Because infants under 6 months have such small stomachs, low body mass and such underdeveloped kidneys, even the smallest amount of water can be fatal. In the end, babies simply don’t need water, they only need their breastmilk or formula. So why risk their life for something they really don’t need at all?

What about babies 6-12 months of age?

From 6-12 months of age, you can introduce water to your child. It’s important to note that babies still need mostly milk and some solids for hydration caloric and nutritional needs, so it’s still very important to ensure that they don’t drink too much water to fill them up. Water intoxication is also still a risk; therefore, water should be kept at a minimum. At this age it’s more for playing, discovering and developing the skills needed to drink water from a cup, than it is to drink the water. Breastmilk especially will still offer most hydration needed until at least 12 months of age.

How to offer water to 6-12-month-olds and how much?

You can offer small amounts of water, about 60ml per day in a sippy cup or an open cup, which is more than enough, though as the months go by and baby starts enjoying water more, you can give up to a 100-120ml per day. Usually, 60ml per day is more than enough to begin with. Open cups are preferred as it helps babies develop the needed fine motor skills to drink from a glass or cup, it’s also a great opportunity for them to develop some more hand and eye coordination. Bottles should never be used for water, as overfeeding is very possible by bottle. You can offer water with solids in the beginning, but as the months go by you can have water available to them during the day too. Remember, water in the first year is more for learning than it is for consumption, so keep it to the minimum. If your baby seems thirsty, offer some milk first.

What about after 12 months of age?

From 12 months of age, breastmilk will still offer a big part of hydration to a toddler, but it’s important that they receive additional water too. At this age they will begin to need water, and it will no longer be about learning, but rather about the consumption. Breastmilk is still incredibly important, and so is solids. So always ensure that water doesn’t fill them up too much that they consume less milk and solids. They won’t need liters of water a day like an adult either, it is recommended that a toddler consumes about 220+ml water per day or more. You can also have milk available to them throughout the day, as they need it.

Additional information and resources:

‘And not a drop to drink’–why water is harmful for newborns


Infant formula

Human Milk Composition: Nutrients and Bioactive Factors

Components of human breast milk: from macronutrient to microbiome and microRNA

No need for water supplementation for exclusively breast-fed infants under hot and arid conditions

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