How much water should a child drink a day?

Updated October 5, 2026 by Kamal Nasir

The American Academy of Pediatrics (AAP) says children aged 1 to 3 need about 4 cups (32 fl oz, about 950 ml) of fluids a day, children aged 4 to 8 about 5 cups (40 fl oz, about 1,200 ml), and older children about 7 to 8 cups, with water and milk both counting, and the National Academies' Dietary Reference Intakes give similar amounts. Babies under 6 months need only breast milk or formula, and from about 6 months just 4 to 8 fl oz (about 120 to 240 ml) of water a day. Children need more in hot weather, during sports and when they are ill.

General information, not medical advice. How these guides are made.

Daily fluid needs by age

These figures, for fluids from drinks, are from HealthyChildren.org (the AAP site for parents), the CDC and the National Academies' Dietary Reference Intakes, which rest on the median intake in a US national survey. A US cup is 8 fluid ounces, about 240 ml, so the metric amounts below are rounded conversions.

• Under 6 months: breast milk or formula only. The AAP says extra water is not recommended at this age.
• 6 to 12 months: about 4 to 8 fl oz of water a day (about 120 to 240 ml), per the AAP and the CDC, because most of their fluid still comes from breast milk or formula.
• 1 to 3 years: about 4 cups (32 fl oz, about 950 ml) of fluids a day, including water or milk, in both the AAP and the National Academies figures.
• 4 to 8 years: about 5 cups (40 fl oz, about 1,200 ml) a day, in both.
• 9 to 13 years: the National Academies give about 7 cups (56 fl oz, about 1,650 ml) for girls and 8 cups (64 fl oz, about 1,900 ml) for boys, matching the AAP's 7 to 8 cups for older children.
• 14 to 18 years: about 8 cups (64 fl oz, about 1,900 ml) for girls and 11 cups (88 fl oz, about 2,600 ml) for boys, the National Academies figures.

A simple check that works at any age

A check anyone can use is the color of pee. The AAP says urine should be very light yellow, almost clear, and lists dark-colored urine among the signs of dehydration. Dark pee is a sign to offer more to drink.

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What counts toward a child's water intake

The AAP says water and milk are all the drinks kids need, and its figure for toddlers includes milk. The CDC says you can begin offering plain whole cow's milk once a child is 12 months old. Water-rich foods add to the total: the AAP lists cucumber, zucchini, celery, tomato, watermelon, cantaloupe and strawberries among good choices, and the National Academies found that food supplied about 29 percent of total water for children aged 1 to 8.

Juice and sugary drinks are where the advice is strict. The AAP says children under 1 should have no juice, children aged 1 to 3 no more than 4 fl oz (about 120 ml) a day, children aged 4 to 6 no more than 4 to 6 fl oz (about 120 to 180 ml), and children aged 7 to 18 no more than 8 fl oz (about 240 ml). It advises no sugar-sweetened drinks for children under 2.

When children need more

Heat, sports and illness all raise the need. The AAP says children aged 9 to 12 who are exercising hard or sweating generally need about 3 to 8 fl oz (about 90 to 240 ml) of water every 20 minutes, and teens about 34 to 50 fl oz (about 1,000 to 1,500 ml) an hour, with water before, during and after practice. If a child is sick and vomiting, the AAP suggests small sips every few minutes, aiming for at least 1 fl oz (30 ml) an hour: breast milk or formula for babies 6 to 12 months, and an oral rehydration solution from age 1.

Signs a child is not drinking enough

The AAP lists these common signs of dehydration:

• Dry lips, a dry or sticky mouth, or thirst
• Peeing less often, or dark-colored pee
• Being unusually sleepy or irritable, or playing less than usual
• In babies: fewer than six wet diapers a day, few or no tears when crying, or a sunken soft spot on the head
• In teens: light-headedness, cramps, headache or a rapid pulse

When to get medical help

The AAP says to call your child's doctor right away if your child is too sick to drink, becomes lethargic, or shows any of the signs above, including weakness or dizziness on standing in an older child. In heat illness, the AAP says to go to the emergency room or call 911 if a child becomes extremely lethargic or unresponsive, vomits, stops sweating or has severe belly pain. If your child has a condition that affects how much they should drink, follow your doctor rather than any chart.

Making it easy to keep track

The AAP suggests drinking water yourself so children copy you, serving water with meals and snacks, packing bottles before you leave the house, and letting children choose a special cup or bottle.

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