Is it safe to give water to a baby and at what age?

We've investigated what the correct and safe advice is and when you might give your baby water safely.

The expert view - is it safe to give your baby water?

Anne Richley, Matron for Community Midwifery Service at Northampton General Hospital NHS Trust, explains that babies under the age of 6 months shouldn't need additional water (unless advised by a healthcare professional). "Babies under 6 months only need milk for all their nutritional and developmental needs. If you give babies water as well, this can fill them up when they still need the nutritional benefits of milk."

But boiled sterile water in itself isn't dangerous or toxic for a baby - unless given in excess. The risk is that your baby may fill up on water, and so not get the nutrients they need from milk feeds.

But if you have given your baby small amounts of water, please don't worry.

"Mums shouldn't panic if they've given their baby a few sips of water," advises Anne.

"This needs to be kept in perspective. We're really only talking about water being life-threatening when given in excess. And an excess of anything can be dangerous for adults, children or babies."

This advice is echoed by the Royal College of Midwives. The RCM's Professional Policy Advisor Janet Fyle confirms that healthy babies under 6 months shouldn't need water. "If you're worried that your baby is dehydrated, you should talk to your doctor," she adds.

In hot weather, how do you make sure your baby is getting enough fluids?

"If you're breastfeeding, your milk will automatically adjust itself – becoming more or less watery – to stop your baby getting thirsty, even in very hot weather," explains Anne.

"If you're formula-feeding and your baby seems thirsty, it's fine to give them an additional bottle of milk. If they don't want it, they won't take it."

Should I dilute my baby's formula or expressed milk?

No, the NHS is very clear on this. You should not dilute the milk you give your baby as this means you can't be sure your baby is getting the nutrients they need from their milk.

Is it safe to give your baby water when they're 6 months or older?

Yes, it is safe, but again, you don't want to fill your baby up with water as you still want them drinking milk and eating solid food. Water is better for their health and teeth than fruit juice or sweetened drinks, and drinking water is a great habit to introduce early on.

If you're just giving water, you can get this straight from a kitchen tap. There's no need to boil drinking water for a baby over 6 months. However, you should still use boiled water for making up bottles, as this helps to sterilise the milk powder.

Sleeping baby being held by dad in nursery room — Credit: Getty Images

How do you know if your baby is showing signs of dehydration?

Babies can get dehydrated if they don't drink enough fluid, and there are signs to look out for...

Your baby should have at least 6 wet nappies in a 24-hour period - from 5 days old. Obviously babies vary, so look out for a change in your baby's weeing habits
Your baby's urine appears darker yellow and more concentrated
Your baby seems listless, drowsy and lacking in energy
Your baby cries but with few or no tears
Your baby's skin seems dry and doesn't bounce back when gently pressed
Your baby's mouth or lips are dry
The soft spot on the top of your baby's head (called the fontanelle) sinks inwards
The NHS adds that your baby's feet may feel cold or look blotchy

If you are worried about your baby's hydration, speak to your doctor or call 111 to talk to a health professional.

Find out more about dehydration in babies and children from the NHS.

Where did the baby water warning story originate?

It appears that initially Buzzfeed quoted a dietician from Mayo Clinic in Arizona, USA, saying "babies don't need water... at all", that they shouldn't drink water before 6 months and that it "is possible for a baby to die drinking too much water" under the scary headline "This Is Why You Should Never Give Your Baby Water". The story ran with the graphic below, showing comments from forums and social media.

why-it-wont-kill-your-baby-if-you-give-him-or-her-a-sip-of-water_166613

The Mirror then picked up the story with the headline, "Why you should NEVER feed your baby water – and how it could be fatal if you do." It still surfaces on Google and is often reshared during hot spells and heatwaves.

In a nutshell

Babies under 6 months shouldn't need additional water. If breastfeeding, feed your baby when they need it (and your amazing breastmilk will adjust to your baby's thirst needs). If bottlefeeding, it's fine to give the occasional extra bottle of milk (not just water), if your baby wants it. Cool boiled water isn't in itself dangerous to your baby, it just has the risk of filling up your baby so they don't drink as much essential milk. If you're worried that your baby is excessively thirsty or may be dehydrated, speak to a health professional.