How much water should a child drink a day?

How much water a child needs, by age

Children aged 1 to 3 need about 4 cups (32 oz, roughly 950 ml) of fluid a day, according to the American Academy of Pediatrics — and that count includes milk as well as water.¹ It rises to about 5 cups for 4- to 8-year-olds and 7–8 cups for older children.¹

In real life, a toddler’s day might be 2 cups of milk with meals and about 2 cups of water through the day. That’s it — no special drinks, and no need to measure every sip.

The two sets of numbers agree closely. The AAP gives a rounded cup count for drinks;¹ the U.S. National Academies’ Adequate Intakes split water into what comes from drinks and what comes from food.³ Boys and girls need the same amount until age 9, when the National Academies start giving separate figures.³

These are averages, not targets for every child on every day. The National Academies based them on what healthy U.S. children actually take in, and say a wide range of intakes is compatible with normal hydration.³ The AAP adds that the amounts vary from child to child and go up with physical activity, heat and humidity.¹

Does milk count? What about food?

Milk counts. The AAP’s 4 cups for toddlers is “fluids, including water or milk.”¹ Here’s how it splits for younger children:

• 12 to 24 months: about 2 cups (16 oz) of whole milk and 1–4 cups (8–32 oz) of water a day.²
• 2 to 5 years: 2–3 cups (16–24 oz) of milk, nonfat or low-fat from age 2, and 1–5 cups (8–40 oz) of water.²

So a 2-year-old who drinks 2 to 3 cups of milk needs only about 1 to 2 more cups (240–475 ml) of water to reach the AAP’s total. If you’re wondering whether your toddler is drinking too much milk, our guide to how much milk a toddler should drink covers the limits.

Food counts too. In the National Academies’ figures, food supplies about 24% to 30% of children’s total water.³ Foods with a lot of water, such as many fruits and vegetables, add to fluid intake.⁵ Soup, yogurt, cucumber, oranges and melon all help. For toddlers and preschoolers, cut fruit and vegetables into small pieces: quarter grapes and cherry tomatoes, cut melon rather than serving it in balls, and skip chunks of hard raw vegetables.⁶

Your child doesn’t need to drink their whole number as plain water. Milk, food and water all add up.

Which drinks are best?

The AAP keeps it simple: the best drinks for young children are water and plain milk.² Tap water also brings fluoride where the supply is fluoridated, which helps prevent tooth decay.²

Sodas, sports drinks, fruit drinks, lemonade and sweetened waters are drinks the AAP calls harmful to children’s health.² Juice isn’t needed either. If you do serve 100% juice, the AAP’s limits are none before age 1, no more than 4 oz a day for ages 1 to 3, 4–6 oz for ages 4 to 6, and 8 oz for ages 7 to 18.¹ See how much juice a child should drink for tips on serving it. For more on sweet drinks, see how much sugar a toddler should have.

Getting a reluctant drinker to drink more

Thirst works well in healthy children. The National Academies note that thirst, combined with drinking at meals, keeps hydration at normal levels day to day.³ Offering water regularly matters more than hitting an exact number.

Hot days and sports

Children need more on hot, humid days and when they’re active.¹ For sport, the AAP advises water before, during and after practices and games. Children aged 9 to 12 generally need about 3–8 oz of water every 20 minutes when exercising hard or sweating.¹

Plain water is the right drink for nearly all kids’ activity. The AAP says electrolyte drinks may be needed only when vigorous exercise goes beyond an hour or a child is sweating a lot.¹ See what young athletes should eat for game-day food, and can toddlers drink Gatorade for why sports drinks aren’t for little ones.

What about babies?

Babies under 6 months should have only breast milk or formula — the AAP does not recommend extra water at this age.¹ From around 6 months, you can offer small sips of water from a cup, about 4–8 oz a day until their first birthday.¹² Cow’s milk as a drink waits until 12 months.² Our guide to when babies can have water covers amounts by age and how to offer it.

How to tell if your child is drinking enough

The easiest check is in the bathroom: pee should be very light yellow, almost clear.¹ Signs an older child needs more to drink include dry lips or a sticky mouth, peeing less or dark-colored pee, being sleepy and irritable, and flushed skin.¹

These are signs of dehydration, and the AAP advises calling the pediatrician straight away if any of them appear.⁴ If your child is vomiting or has diarrhea, our guide to Gatorade and toddlers explains what to give instead.

Common questions