Last updated: September 2026
How much water should a child drink a day? The American Academy of Pediatrics puts it at about 4 cups of total fluids for ages 1 to 3, about 5 cups for ages 4 to 8, and 7 to 8 cups for children 9 and older, with more on hot days and sports days. Babies 6 to 12 months can have 4 to 8 ounces of water a day alongside breast milk or formula, and babies under 6 months should not have plain water at all. The chart below breaks it down by age and explains what counts toward the total.
Key takeaways
- No water before 6 months. From 6 to 12 months, 4 to 8 ounces a day is plenty.
- Toddlers need about 4 cups of fluid a day, school-age kids about 5, and children 9 and up 7 to 8 cups, per the AAP.
- Milk counts. Juice is limited by age. Sports drinks are only for long, hard, hot exercise. Energy drinks are never appropriate.
- Dark urine, headaches, fewer bathroom trips, and constipation are the everyday signs your child is not drinking enough.
How much water should a child drink a day by age?
The numbers below come from the AAP’s HealthyChildren.org guidance. They describe total daily fluid (water plus milk), not water alone, for children over 1. Every child is different, and the AAP notes that amounts should be adjusted for activity level and weather. [Source: AAP HealthyChildren.org, Choose Water for Healthy Hydration]
| Age | Daily fluid target | What it should be |
|---|---|---|
| Birth to 6 months | Breast milk or formula only | No plain water |
| 6 to 12 months | 4 to 8 oz water (about 0.5 to 1 cup) | Plus breast milk or formula as usual; no juice |
| 1 to 3 years | About 4 cups total fluid | Water plus about 2 cups of milk; juice 4 oz or less |
| 4 to 8 years | About 5 cups total fluid | Water plus 2 to 3 cups of milk; juice 4 to 6 oz or less |
| 9 to 13 years | 7 to 8 cups total fluid | Mostly water; juice 8 oz or less |
| 14 to 18 years | 7 to 8 cups, more with sports and heat | Mostly water; no energy drinks |
For the youngest children, the AAP’s separate guide for ages 0 to 5 gives water ranges of 1 to 4 cups a day at 12 to 24 months (with 2 cups of whole milk) and 1 to 5 cups a day at 2 to 5 years (with 2 to 3 cups of low-fat or nonfat milk). [Source: AAP HealthyChildren.org, Recommended Drinks for Children Age 5 and Younger]
Why do children need so much water?
A child’s body is a larger share of water than an adult’s, and it turns fluid over faster. Children gain heat from the environment faster, yet the AAP notes that kids have lower sweat rates than adults, which makes cooling less efficient. [Source: AAP HealthyChildren.org, Extreme Heat: Tips to Keep Kids Safe]
Water lets the kidneys flush waste, keeps stool soft, and holds body temperature steady. When intake falls short, the first change is often behavioral: a child who is cranky or unable to focus by mid-afternoon. The CDC states that staying hydrated may improve cognitive function in children and adolescents, which is part of why it pushes schools to make free drinking water available throughout the day. [Source: CDC, Water Access in Schools] We cover the bigger picture in our post on the importance of hydration in kids.
Does my child need more water for fall sports in Georgia?
Yes. September and October practices in Cobb and Forsyth counties routinely start in the high 80s, and heat index readings of 90 are common. The AAP flags a heat index at or above 90 degrees as a caution point for children and 105 or above as a danger day when outdoor time should be limited. [Source: AAP HealthyChildren.org, How to Keep Young Athletes Safe in Hot Weather]
For practice and game days, the AAP suggests:
- Drink before you start. A 70-pound child should have 8 to 10 ounces of water 2 to 3 hours before exercise and another 6 to 8 ounces right before. [Source: AAP HealthyChildren.org, Sports Nutrition for Busy Families]
- Sip during. Roughly 3 to 4 ounces every 15 minutes, or for 9 to 12-year-olds, 3 to 8 ounces every 20 minutes of vigorous activity.
- Build up over 7 to 14 days. Kids starting a new season or a new sport need time to acclimate before full-length outdoor sessions.
Heat exhaustion looks like muscle cramps, dizziness, headache, nausea, heavy sweating or cold clammy skin, and confusion. Stop, get to shade, and drink. A body temperature above 104 degrees with fainting, confusion, or seizure is heat stroke, and that is a 911 call. Athletes also need a current sports physical on file before the season starts.
What are the signs my child is not drinking enough?
Most under-hydrated kids are not sick, just busy. Watch for these everyday clues:
- Dark yellow urine. Pale straw color is the goal. Apple juice color means catch up.
- Fewer bathroom trips. A school-age child who goes only once or twice during the day is behind.
- Headaches and afternoon crankiness.
- Constipation. Hard, infrequent stools are often a fluid and fiber problem. See our guide to constipation in children.
- Dry lips and a dry mouth.
True dehydration, which usually comes with vomiting, diarrhea, or fever, is a different level of concern. In infants, the AAP lists fewer than 6 wet diapers a day, no tears when crying, a sunken soft spot, and unusual sleepiness as reasons to call the pediatrician right away. Severe signs include extreme irritability, sunken eyes, cool and discolored hands and feet, and urinating only once or twice in a day. [Source: AAP HealthyChildren.org, Signs of Dehydration in Infants and Children] Any of those warrants a same-day call, and a child who cannot keep fluids down, is limp, or is hard to wake should go to the emergency room. We have age-specific detail in signs of dehydration in babies and signs of dehydration in toddlers, plus a guide to how many wet diapers a 1-year-old should have.
What counts toward my child’s daily fluid?
Milk counts fully. The AAP’s targets above are for total fluid, and 2 to 3 cups of milk a day is part of the plan for children 1 to 8.
Fruit and vegetables count partly. Watermelon, cantaloupe, strawberries, cucumber, celery, and tomato are mostly water and are a good way to top off a child who resists drinking.
Juice is capped by age. None before age 1. No more than 4 ounces a day for ages 1 to 3, 4 to 6 ounces for ages 4 to 6, and 8 ounces for ages 7 to 18. Whole fruit is the better choice, and we explain why in how much sugar is too much for children.
Sports drinks are for a narrow situation. Water is enough for activity under an hour. For sessions longer than 1 to 2 hours, or in very hot conditions with heavy sweating, a sports drink can replace carbohydrates and electrolytes.
Energy drinks are never appropriate for children or teens. The AAP is direct on this: they carry caffeine and excess sugar and are not recommended at any age under 18.
How do I get a picky child to drink more water?
Keep it simple and keep it visible:
- Give each child their own bottle and let them pick it. A cup they like gets used.
- Send a full bottle to school every day and check the level at pickup.
- Serve water with every meal and snack, first, before anything else is offered.
- Flavor it without sugar: lemon or orange slices, frozen berries as ice cubes, cucumber, or mint.
- Put out high-water fruits and vegetables as snacks.
- Drink water yourself. Children copy what they see far more than what they are told.
Can a child drink too much water?
For healthy children over a year old, normal drinking from a cup does not cause harm. The risk is real for babies under 6 months. Their kidneys are immature, and their bodies are small enough that even a few ounces of extra water can dilute the sodium in their blood. The result is water intoxication, which can cause seizures. This is also why formula must never be watered down. The AAP states that formula diluted with too much water can cause serious health and developmental problems. [Source: AAP HealthyChildren.org, How to Safely Prepare Baby Formula With Water]
If a baby under 6 months seems thirsty in the heat, offer more breast milk or formula, not water. Our guide to how often a newborn should eat covers what normal intake looks like, and how many wet diapers a newborn should have tells you whether they are getting enough.
How Sun Pediatrics can help
If your child has recurring headaches, constipation, or trouble staying hydrated during sports, bring it up at a well visit. Every physician is board certified, and our team cares for children from birth through 18 at our Marietta, East Cobb, Alpharetta, and Cumming offices.
When a stomach bug hits and you are worried about dehydration, we offer same-day sick visits every day and secure video visits when you are not sure a trip in is needed. We also do sports physicals and well visits. Hours are Monday to Thursday 8:00 to 4:45, Friday 8:00 to 4:15, and a Saturday clinic 9:00 to 12:00 on the 1st and 3rd Saturday. Request an appointment online or call 678-501-5601. Same-day sick visits are held every day at all four offices.
Frequently asked questions
How many ounces of water should a 2-year-old drink a day?
About 4 cups of total fluid, which usually works out to 2 cups of milk plus 1 to 2 cups (8 to 16 ounces) of water. More on hot days or when your toddler is very active.
Can I give my 4-month-old water in hot weather?
No. Babies under 6 months should get only breast milk or formula, and extra water can dilute their blood sodium and cause water intoxication. Offer more breast milk or formula instead.
Should my 10-year-old drink Gatorade at soccer practice?
Only if practice runs longer than an hour or two in real heat with heavy sweating. For a typical 60- to 90-minute practice, water is enough. Energy drinks are never appropriate.
How can I tell if my child is drinking enough at school?
Check the water bottle at pickup and check urine color at home. Pale yellow means they are fine. Dark yellow, a headache, or only one bathroom trip all day means they need to drink more tomorrow.
Does milk count as water?
Yes. The AAP’s daily fluid targets include both water and milk, and 2 to 3 cups of milk a day is part of the recommendation for children 1 to 8.
This article is for general information and is not medical advice. Contact your pediatrician for care specific to your child.
