Can babies drink water?

For most babies, you can start offering water from around six months, at the same time as you introduce solid foods. Before then, milk is doing two jobs. It provides your baby with nutrition, but it also provides the fluid they need.

An exclusively breastfed baby does not routinely need additional water during their first six months, even when the weather is warm. You might notice them wanting to breastfeed more frequently instead. WHO defines exclusive breastfeeding as breastmilk without other foods or liquids, including water, for the first six months.

Formula-fed babies also get fluid from their normal milk feeds. There is one exception that often surprises parents: during hot weather, the NHS advises that formula-fed babies under six months may need small sips of cooled boiled water in addition to their usual milk feeds.

From around six months, water gradually becomes part of everyday mealtimes.

Water and babies at a glance

These are guidelines rather than targets. There isn’t a magic birthday when your baby suddenly needs to start drinking a certain quantity of water.

This is probably the question parents most want a number for, but there isn’t a set amount of plain water in millilitres or ounces that every six month old needs to drink.

When your baby first starts solids, offer a few sips of water with meals. Their breastmilk or formula is still providing a large proportion of their fluid at this stage.

As a Health Visitor, I’d much rather parents look at their baby than become fixated on the number of millilitres disappearing from a cup. At six months, drinking from a cup is a completely new skill. Some babies take to it immediately. Others take one sip, chew the cup and then pour the rest over themselves.

All of that is normal.

As your baby eats more solid food, keep offering water regularly and let them decide how much they want. The NHS advises that breastmilk or first infant formula should remain their main drink throughout the first year.

Parents often worry about whether their baby is drinking enough, particularly during illness or warm weather. Rather than focusing on the cup alone, look at your baby as a whole.

Things that may suggest dehydration include:

If your baby is unwell, feeding significantly less than usual or having noticeably fewer wet nappies, seek medical advice.

Yes, which is one reason we don’t recommend routinely giving young babies water.

A baby has a very small stomach. If they fill up on water, they may take less breastmilk or formula and therefore miss out on calories and nutrients they need for growth.

Large amounts of water can also dilute the sodium in the blood and cause an electrolyte imbalance known as hyponatraemia. This can be dangerous.

It’s also why you should never add extra water to formula powder in an attempt to keep your baby hydrated. Formula should always be prepared using the exact proportions stated on the packaging.

One misconception I come across is that formula-fed babies routinely need drinks of water because formula is somehow less hydrating. For most babies, that isn’t the case.

Breastfed babies

Breastmilk provides the fluid an exclusively breastfed baby needs during their first six months. If the weather becomes warmer, you may notice your baby asking to feed much more frequently, sometimes having lots of short feeds.

You don’t need to try to stretch those feeds out or substitute them with water. Follow your baby’s cues and offer the breast when they want it.

Formula fed babies

Correctly prepared first infant formula also provides fluid as well as nutrition.

During particularly hot weather, a formula fed baby under six months may sometimes need small sips of cooled boiled water alongside their normal feeds. Their formula feeds should continue as usual.

The important thing is never to make a bottle weaker by adding additional water. It might seem like a sensible way to increase fluids, but it changes the nutritional balance of the feed.

Breastfed and Formula-Fed Hydration at a Glance

If you’ve spent the first six months thinking carefully about milk feeds, it can be tempting to approach water in exactly the same way and start measuring it. You really don’t need to.

Start simply:

I’d also avoid constantly following your baby around trying to persuade them to drink. Offering water regularly and allowing them to respond to their own thirst is a much more relaxed way to establish the habit.

For most babies over six months in the UK, ordinary fresh tap water is absolutely fine and doesn’t need to be boiled before drinking.

There are, however, slightly different rules when water is being used to prepare infant formula.

Tap water

For drinking from around six months, fresh tap water is generally the easiest option.

For powdered infant formula, use fresh water from the cold tap. The NHS advises boiling at least one litre of fresh tap water and allowing it to cool for no more than 30 minutes, so it remains at least 70°C when the formula is made. This is important because powdered infant formula itself isn’t sterile.

Filtered water

Having a water filter doesn’t make water sterile, so I wouldn’t assume filtered water needs different safety rules simply because it has passed through a filter.

Filters also need cleaning and replacing according to the manufacturer’s instructions. If they aren’t maintained properly, bacteria can build up.

Hard and soft water

Living in a hard water area doesn’t mean you need to buy special water for your baby.

What you do need to be aware of is artificially softened water. The NHS advises against using artificially softened water to make infant formula. Use fresh water from the cold mains tap instead.

Can babies have bottled water?

Bottled water isn’t necessarily a better choice for babies just because it comes in a bottle.

The NHS does not usually recommend bottled water for preparing infant formula because it isn’t sterile and may contain too much sodium or sulphate.

If your mains water supply has been contaminated or you’re somewhere without safe tap water, follow the specific advice given by the relevant health or water authority.

If you’re travelling abroad with a baby, it’s worth checking local water and formula preparation advice before you go rather than trying to work it out when you arrive.

“Newborns need water when it’s hot.”

Usually, no. Breastfed babies may want to feed more frequently when it’s hot. Formula-fed babies should continue their normal feeds, although the NHS advises they may sometimes need small sips of cooled boiled water during hot weather.

“Adding extra water to formula will keep my baby hydrated.”

Please don’t do this. Formula needs to be made exactly according to the manufacturer’s instructions. Adding extra water means your baby receives less nutrition and can also disturb their electrolyte balance.

“Once my baby drinks water, they don’t need as much milk.”

Water being introduced doesn’t mean milk suddenly becomes unimportant. Breastmilk or first infant formula should remain your baby’s main drink throughout their first year.

“My baby won’t drink water, so I should offer juice instead.”

There’s no need to replace water with juice. Some babies simply take longer than others to get used to drinking water. Keep offering it without pressure and give them time.

I think one of the easiest traps to fall into is turning hydration into another thing to count.

Instead, look at the bigger picture.

Is your baby feeding normally? Are you changing their usual number of wet nappies? Are they alert and behaving like themselves? Those things tell us much more than whether they drank 20 ml or 50 ml with lunch.

In warmer weather, give your baby more opportunities to feed or drink according to their age. If they’re over six months, having their cup available at mealtimes and offering water at other points during a hot day is absolutely fine.

Illness is slightly different. Vomiting, diarrhoea and fever can all increase the risk of dehydration. WHO guidance also recommends increasing fluids during illness, including more frequent breastfeeding. If your baby is struggling to keep fluids down, feeding much less than normal or producing noticeably fewer wet nappies, seek medical advice.

And when you first introduce a cup, don’t worry if more water ends up on your baby than in them. They’re learning.

So, can babies drink water? Yes, but for most babies it’s something we introduce from around six months, alongside solid foods.

Start with a few sips at mealtimes and let your baby gradually get used to drinking from a cup. There’s no need to chase a particular number of millilitres at six months, and breastmilk or first infant formula should remain their main drink throughout their first year.

Before six months, babies usually get the hydration they need from their milk. If you’re worried about your baby’s fluid intake, particularly during illness or very hot weather, ask your health visitor or another healthcare professional for individual advice.

For more expert guidance on baby nutrition and hydration, explore HiPP Organic’s resources.