How much water do children need? A guide by age

2026-10-30

Children need less water than adults in total, but more for their size, and the amount grows quickly with age. According to the European Food Safety Authority, a toddler of 2 to 3 needs about 1.3 liters (44 fl oz) of total water a day, a child of 4 to 8 about 1.6 liters (54 fl oz), and a 9 to 13 year old about 1.9 liters (girls) to 2.1 liters (boys). That's total water, including milk and the water in food, so the amount kids actually drink is lower. Babies under six months need no water at all beyond breast milk or formula.

Water needs by age

These are the adequate intakes of total water (drinks plus food) from EFSA's reference values for water. They assume a moderate climate and moderate activity.

0–6 months: 100–190 ml per kg of body weight a day, all from breast milk or formula.
6–12 months: 800–1,000 ml (27–34 fl oz).
1–2 years: 1,100–1,200 ml (37–41 fl oz).
2–3 years: 1,300 ml (44 fl oz).
4–8 years: 1,600 ml (54 fl oz).
9–13 years: girls 1,900 ml (64 fl oz), boys 2,100 ml (71 fl oz).
14 years and up: adult values, 2.0 liters for girls and 2.5 liters for boys.

The US National Academies give somewhat higher figures, and they helpfully split out the share from drinks:

1–3 years: 1.3 liters total, about 0.9 liters (4 cups) from drinks.
4–8 years: 1.7 liters total, about 1.2 liters (5 cups) from drinks.
9–13 years: girls 2.1 liters total, about 1.6 liters (7 cups) from drinks; boys 2.4 liters total, about 1.8 liters (8 cups) from drinks.
14–18 years: girls 2.3 liters total, about 1.8 liters (8 cups) from drinks; boys 3.3 liters total, about 2.6 liters (11 cups) from drinks.

Neither set is a precise prescription. They describe what healthy children typically take in. A child who plays football in July needs more than one reading on the sofa in November. For how these reference values work in adults, see how much water you should drink a day.

Babies under 1

Under six months, breast milk or formula provides all the water a baby needs, even in warm weather. The NHS notes that breastfed babies don't need any water until they start solids, and formula-fed babies may need small sips of cooled boiled water in hot weather. Giving young babies extra water can fill them up without the nutrients they need, so check with your health visitor or pediatrician before offering it.

From around six months, when solids start, you can offer small sips of water with meals from an open or free-flow cup. Milk remains the main drink for the first year.

What children should drink

Water and milk are the two drinks health services recommend for children:

Water is the best everyday drink: no sugar, no calories, nothing to harm teeth.
Milk is a good drink after age one (whole or semi-skimmed for young children). It counts toward fluids and brings protein and calcium, but large amounts can crowd out food.
Fruit juice isn't needed. If you give it, the NHS suggests diluting it and keeping it to mealtimes; from age 5, no more than one small glass (about 150 ml) a day.
Squash, soft drinks and flavored milks are a major source of sugar and tooth decay in children. Even diluted or "no added sugar" versions are best kept off the everyday menu.
Energy drinks and caffeinated drinks aren't suitable for children.

Why kids can get dehydrated more easily

Children have a larger body surface relative to their weight, and young ones depend on adults to offer drinks. They also get absorbed in play and simply forget. The NHS lists babies and children among the groups more at risk of dehydration, especially with fever, vomiting or diarrhea, or in hot weather.

Signs to watch for in children:

Fewer wet diapers, or peeing less often than usual
Dark yellow urine
Dry mouth, lips or tongue
Unusual tiredness, irritability or headache
Few or no tears when crying

For stomach bugs and fever, see what to drink when you're sick; oral rehydration solutions are designed for exactly this.

Practical tips for parents

Make water the default. If water is what's on the table at every meal, it becomes normal. Kids drink what's available.
Offer, don't wait to be asked. Young children often don't say they're thirsty. Offer a drink at meals, snacks, after play and after nursery or school.
Give them their own bottle. A bottle they chose themselves, in a size they can carry, is more likely to be used. A good starting point: one bottle to school, refilled at lunch.
Check school routines. Many kids avoid drinking at school because they can't access water easily or don't want to ask to go to the toilet. Ask what the rules are.
Add flavor without sugar. Slices of orange, cucumber or berries in water, or fizzy water, can make plain water more interesting. More ideas in 12 ways to make water easier.
Use water-rich food. Fruit, vegetables, soups and yogurt all contribute.
Plan for sport and heat. For most children's activities, water is enough; sports drinks are rarely needed and add sugar (see sports drinks vs water). Drink before, take breaks during, and drink after.
Model it. Children copy what adults do. If they see you refilling your bottle, they're more likely to refill theirs.

Do children need to track their water?

Mostly, no. Offering water regularly and keeping sugary drinks occasional is enough for most kids. Teenagers with their own iPhone or Apple Watch may like tracking, though, especially if they play sport. In Water Tracker, the suggested goal is designed for adults, so a teen should adjust it in Settings to their age (the values above are a good guide) and can pick a smaller glass size. For younger kids, a sticker chart on the fridge does the same job.

When to talk to a doctor

See your pediatrician or GP if your child seems thirsty all the time and drinks unusually large amounts, pees a lot more than usual, or wets the bed after being dry; these can be signs of conditions such as diabetes. Also seek advice for any child with kidney or heart problems, or signs of dehydration that don't improve.

The bottom line

Children's total water needs rise from about 1.1–1.2 liters a day at age one to about 1.6 liters at 4–8 years and around 2 liters by early adolescence, including milk and food. Babies under six months need only breast milk or formula. Make water the default drink, offer it often, limit juice and sugary drinks, and watch for fewer wet diapers or dark urine.

This article is general information, not medical advice. If you have a health condition, are pregnant or take medication, ask your doctor how much you should drink.