“Should I give the baby some water?” is one of those questions that feels like it should have an obvious answer — and the answer genuinely surprises many new parents. For young babies, water isn’t just unnecessary; too much can be harmful. Here’s a clear, age-by-age guide to when and how to offer it safely.
Why don’t young babies need water?
For roughly the first six months, breast milk or formula provides everything your baby needs to stay hydrated — even in hot weather. Milk is mostly water, and a baby feeding well is getting plenty of fluid. Topping up with extra water doesn’t help, and it carries a real risk.
A small baby’s kidneys aren’t mature enough to handle much plain water. Drinking too much can dilute the level of sodium in their blood — a condition called water intoxication or hyponatraemia — which in severe cases can cause serious problems. Extra water can also fill a small tummy, so a baby takes less milk and misses out on the calories and nutrients they need to grow.
That’s why the guidance is clear: don’t give water to a baby under about six months unless your healthcare provider specifically tells you to (occasionally they might, for a particular medical reason). If your baby seems thirsty in hot weather, the answer is simply more frequent milk feeds, not water.
When can babies start drinking water?
Things change at around six months, when most babies start solids. This is the natural point to introduce small amounts of water — and it’s as much about learning a new skill as it is about hydration:
- Offer small sips of water with meals.
- Use an open cup or a free-flow (non-valve) cup to help your baby learn to sip rather than suck, which is better for developing teeth and mouth muscles.
- Keep milk — breast or formula — as the main drink for the whole first year.
You don’t need to push a particular amount. A few sips alongside meals is plenty at first, and your baby will gradually take more as they get used to it. As solids and drinking develop together, our feeding & weaning planner maps what to expect month by month.
How much water for a toddler?
Once your baby passes their first birthday, water becomes a normal part of the day, sitting alongside milk and the fluid they get from food. There’s no need to measure precisely, but as a rough guide:
- 6–12 months: small sips with meals, perhaps 60–120 ml (2–4 oz) a day total — milk still leads.
- 12–24 months: roughly 1–4 cups (about 240–960 ml) of water a day.
- 2 years and older: around 4–5 cups (1–1.3 L) a day.
These are general ranges, not targets to enforce. Needs shift a lot with weather, activity, illness and how much milk your toddler still drinks. Offer water regularly, especially in heat or after active play, and let thirst do most of the guiding. Our baby water intake guide gives the age-appropriate amount when you enter your baby’s age.
What kind of water — and what about juice?
Once your baby is six months and drinking small amounts, plain tap water is usually fine where the supply is safe to drink, offered cold or at room temperature straight from the tap. Before that age, water used to make up formula should be freshly boiled and then cooled, following the instructions on the tin — that’s a separate matter from giving a baby water to drink, and the boiling step is about safely preparing the feed. Bottled water isn’t necessary for most families; if you do use it, check it’s low in sodium and sulphate, and still boil and cool it for formula under six months.
What babies and toddlers don’t need is sugary drinks. Fruit juice, squash, flavoured milks and fizzy drinks aren’t recommended in the early years — they add sugar, can crowd out milk and food, and aren’t kind to emerging teeth. If you ever offer a little diluted juice with a meal in toddlerhood, keep it occasional. For everyday thirst, water and milk are the two drinks that matter, and plain water is the perfect choice once your baby is old enough for it.
How can you tell your baby is well hydrated?
You don’t need to track millilitres to know your baby is getting enough fluid. The most reassuring sign is regular wet diapers — roughly six or more a day for younger babies — with pale, mild-smelling urine. A baby who is feeding well, alert and content is almost always well hydrated.
Signs that a baby might be dehydrated and needs prompt attention include far fewer wet diapers than usual, a dry mouth, no tears when crying, unusual drowsiness or floppiness, or a sunken soft spot on the head. In hot weather or during illness — especially with vomiting or diarrhoea — keep a closer eye on feeds and diapers, and contact your provider if you’re worried, as babies can become dehydrated quickly.
The simple takeaway
Before six months, milk is all your baby needs — skip the water. From six months, offer small sips from a cup with meals while milk stays the star. Through toddlerhood, water becomes an everyday drink. And at every stage, wet diapers and a content baby are your best reassurance — with your provider as the place to turn for any specific concern.
This article is for general information only and isn’t medical advice. Never give water to a baby under 6 months without guidance, and follow your healthcare provider for advice specific to your baby.