How Much Water Should Kids Drink? Hydration Guide by Age

Ensuring children stay well-hydrated is crucial for their health and development. Water makes up about 50–70% of a child’s body weight and is needed to regulate temperature, transport nutrients, remove waste, and keep joints and tissues lubricated. Kids are especially vulnerable to dehydration because they lose fluids faster (through sweat, urine, etc.) and may not always recognize or communicate thirst. Yet studies show many children may not be drinking enough – for example, U.S. children and teens average only about 23 ounces of plain water per day (less than 3 cups), which is well below recommended levels for most ages. This guide provides a hydration chart for children with daily water intake by age, explains how much water kids should drink, signs of dehydration to watch for, and tips to encourage healthy hydration habits.

Why Hydration Is Important for Children

Water is essential for virtually every bodily function in kids. Adequate hydration helps maintain energy and focus (even mild dehydration can cause fatigue or mood changes) and supports normal physical and cognitive development. Children who drink enough fluids have an easier time regulating body heat and can avoid issues like constipation or kidney stones that can arise from not drinking enough.

Importantly, kids can become dehydrated more quickly than adults. Infants and young children have a higher proportion of water relative to their body size and can lose water rapidly through sweating, breathing, and elimination. They also often depend on adults for access to drinks and might not ask for water until they’re already thirsty. In fact, young children may not feel or express thirst as clearly, so dehydration can sneak up on them. If a child is vomiting, has diarrhea, or is very active on a hot day, their risk of dehydration goes up even further. Keeping an eye on your child’s hydration – and encouraging them to drink fluids regularly – is key to preventing dehydration and keeping their body running smoothly.

Daily Water Requirements by Age

How much water should your child drink per day? The answer depends on age, among other factors. Below is a hydration chart outlining approximate daily water intake for children by age group. These amounts include all sources of fluid – not only plain drinking water, but also other beverages (like milk) and the water content of foods. Keep in mind that individual needs can vary, and kids may need more than these amounts if they are very active or in hot climates.

As the chart shows, daily water intake by age increases as children grow. For example, a toddler may need around 4 cups of fluid a day, while an older child might need 7–8 cups or more. These guidelines align with recommendations from health authorities. The American Academy of Pediatrics (AAP) suggests about 4 cups of fluids per day for ages 1–3, around 5 cups for ages 4–8, and 7–8 cups for older children. Similarly, the European Food Safety Authority (EFSA) advises about 1.3 liters/day for 2–3 year-olds, 1.6 L for 4–8 year-olds, and roughly 1.9–2.1 L for 9–13 year-olds (with boys on the higher end). By the teen years, fluid needs approach adult levels – around 2 to 2.5 liters per day (8–10+ cups), depending on sex and activity level. Always remember these are general targets for healthy kids in normal conditions. It’s wise to adjust for your child’s individual situation – for instance, on days of high activity or high heat, they will require extra fluids.

Infants (0–12 months)

For the first 6 months of life, babies do not need any water aside from breast milk or infant formula. In fact, giving water to young infants is not recommended. Breast milk is 80% water and provides all the hydration an infant needs. The World Health Organization (WHO) and pediatric experts advise exclusive breastfeeding (or formula feeding) for about 6 months – no extra water or juice is needed in this period. Offering water to an infant under 6 months can be harmful, as it fills their tiny stomach and can displace the nutritious milk they require; it may also lead to electrolyte imbalances or increase infection risk.

Once a baby is around six months old and starts eating some solid foods, you can begin offering a little bit of water. Start with small sips in a cup – a total of 4–8 ounces per day (about half a cup to one cup) is plenty at this stage. This small amount helps them practice drinking and stay hydrated as solids gradually replace some milk feedings. Breast milk or formula should remain their primary source of nutrition and fluids until age 1, but a bit of water with meals or in warm weather is okay after 6 months. Keep in mind that infants’ kidneys are still immature, so avoid giving too much water, and never dilute formula with extra water beyond the instructions.

Toddlers (1–3 years)

Toddlers are becoming more active and will need more fluids to keep up with their growing bodies. Around 1 to 3 years of age, children need roughly 4 cups of fluids per day. This includes water as well as milk or other healthy drinks. For instance, if your toddler drinks about 2 cups of milk daily (the AAP recommends 2–3 cups of milk for ages 1–3), the rest of their fluid can come from water. Offering around 1½ to 2 cups of plain water over the day in addition to milk will usually meet their ~4 cup total requirement.

Toddlers can be busy and may forget to drink, so it helps to offer water regularly between meals and during playtime. Provide water with snacks and have a sippy cup or water bottle within your toddler’s reach so they can drink whenever thirsty. You can also offer foods with high water content – juicy fruits like watermelon, orange slices, or grapes, and snacks like cucumber or yogurt. These contribute to hydration while providing nutrients. Keep an eye on urine output and color as a guide: at least several wet diapers or potty visits per day, and urine that is light yellow (not dark), indicates good hydration.

Preschoolers and Young Children (4–8 years)

By the time kids are in preschool or early elementary (around 4 to 8 years old), their daily water needs rise to roughly 5 cups of fluid per day. That works out to about 40 ounces (1.2 liters) in total fluids each day. Again, this total includes all beverages (water, milk, etc.). For example, if a 5-year-old drinks one cup of milk and one cup of juice (juice should be limited – more on that later), they should still drink roughly 3 more cups of plain water throughout the day to hit ~5 cups total.

Practical tips for this age group: give your child a reusable water bottle for school or daycare, and encourage them to finish it and refill if needed. Many young kids need reminders to drink, especially when they’re active or focused on play. Encourage routine water breaks – for instance, have them drink water at recess, with lunch, and after school. Making water easily accessible is key. Children are more likely to drink water if it’s cold and handy, so you might pack a chilled bottle with their lunch or have a pitcher of water and cups available at home within their reach.

Older Children (9–13 years)

Older children (approximately 9 to 12 years, spanning late elementary to middle school) should be drinking around 7–8 cups of fluids daily on average. That’s roughly 56–64 ounces, or about 1.6 to 1.9 liters per day. At this stage, boys and girls have similar water needs, though toward the end of this age range boys may start to require a bit more due to growth spurts and higher muscle mass. In fact, European guidelines (EFSA) recommend about 1.9 L for 9–13-year-old girls and 2.1 L for boys of the same age – which is about an 8 ounce (1 cup) difference. U.S. guidelines from the Institute of Medicine similarly suggest ~9 cups per day for preteen girls and 10 cups for boys.

In practice, aiming for roughly 7 to 8 cups total is a good target for most tweens, adjusting up if the child is very active. Make sure water is the go-to beverage at this age: pack a water bottle in their backpack, encourage water with meals and snacks instead of soda, and continue to limit sugary drinks. As kids approach adolescence, some develop a preference for sweetened sports drinks, soda, or flavored beverages. While an occasional sports drink can be useful during prolonged intense exercise, for everyday hydration water is the best choice. Emphasize to your child that drinking water will help them feel and perform better, especially if they’re involved in sports or outdoor activities.

Teenagers (14–18 years)

Teenagers’ hydration needs are similar to adults. Teen girls require roughly 8–10 cups of fluid per day (around 2 to 2.4 liters), and teen boys around 11–14 cups (about 2.6 to 3.3 liters) per day. The wide range here reflects differences in body size and activity levels – an older teen who is very athletic or going through a growth spurt might be at the higher end. EFSA classifies adolescents 14 and up as having adult water requirements, recommending ~2.0 L/day for females and ~2.5 L/day for males. Many teens, however, do not drink that much and may be chronically under-hydrated if they’re not conscious of their water intake.

Parents and caregivers of teens can encourage good habits by providing large water bottles for school and sports, and by reminding teens that thirst is not always the best indicator – they should drink throughout the day, not just when extremely thirsty. Teenage athletes, in particular, need to be mindful of replacing fluids during training (see Extra Hydration for Exercise below). It’s also wise to educate teens on the drawbacks of excessive sugary or caffeinated drinks. Energy drinks and sodas can actually contribute to dehydration (due to caffeine’s diuretic effect and high sugar causing more urine output), and they add unnecessary calories. Encourage water first and foremost, and if flavor is desired, try adding fruit slices or opting for flavored seltzers with no added sugar.

Special Situations: When Kids Need More Fluids

The recommended intakes above assume a child is healthy and in a moderate environment. Certain situations raise a child’s fluid needs, and parents should be ready to increase the child’s water intake during these times:

• Hot weather: In high heat or humidity, children sweat more and can overheat quickly. They will need extra water to stay cool and compensate for fluid lost through sweat. The Mayo Clinic advises that drinking more water in hot (or even cold, dry) weather helps regulate body temperature and prevent dehydration. On hot days, make sure your child drinks water before going outside, and provide frequent water breaks (at least every 20 minutes during vigorous activity in heat). Encourage them to come indoors periodically to cool off and hydrate.

• Physical activity and sports: Active kids require more fluids, especially during endurance exercise or sports. Don’t wait for a child to say they’re thirsty – by then they might already be mildly dehydrated. In fact, studies on active children found that relying on thirst leads to inadequate drinking and risks dehydration, so it’s important to have a hydration plan. For example, one guideline from the American Academy of Pediatrics is that children 9–12 years old should drink about 3–8 ounces of water every 20 minutes during continuous activity, and teens should drink about 34–50 ounces per hour when exercising heavily. In practice, this means ensuring kids take regular water breaks during sports games or playtime. Before exercise, they should be well-hydrated (a good rule is to drink extra water the evening before and in the hours leading up to strenuous activity). After exercise, they should replenish fluids – drinking enough to quench thirst and produce clear or light-colored urine is a handy sign of rehydration. For prolonged intense exercise over an hour or activities in very hot weather, an electrolyte drink (sports drink or oral rehydration solution) may be helpful to replace salts lost in sweat, but for most routine play, water alone is sufficient.

• Fever, illness, and dehydration from vomiting/diarrhea: When children are sick with a fever, their bodies burn through fluids faster. Fever increases water loss, and if a child isn’t eating or drinking well due to illness, dehydration can occur. Vomiting and diarrhea in particular can lead to rapid fluid and electrolyte loss. According to the Mayo Clinic, children who have vomiting or diarrhea need extra fluids at the first sign of illness – don’t wait until they are seriously dehydrated to act. Offer frequent small sips of water or an oral rehydration solution (ORS) to replace lost fluids and salts. Even if the child doesn’t feel like drinking, encourage small, frequent intake (a few ounces every 15 minutes, for example). If your baby is breastfeeding, nurse more often. For any child who is ill, monitor for signs of dehydration (discussed below) and contact a pediatrician if you suspect dehydration. Note: Babies under 6 months generally shouldn’t be given plain water, but if they have diarrhea your doctor may recommend an appropriate rehydration solution – always consult a pediatrician in the case of infants with illness.

• Cold, dry environments or high altitude: We often focus on hydration in the heat, but cold weather and dry air (or being at high elevations) can also increase water needs. Heated indoor air in winter and the diuresis effect of cold can contribute to fluid loss. The Mayo Clinic notes that in cold or high-altitude conditions, extra fluids can help combat moisture loss from dry air. So even during winter sports or mountain vacations, make sure kids keep drinking water regularly.

In all these scenarios, a good strategy is to schedule regular drinking opportunities. Young kids should take water breaks even if they don't request them, and older kids/teens should be reminded to proactively drink. Pack additional water for school on hot days or if they have gym class. If a child will be outside playing, set a timer or routine (for example, "come drink a cup of water every 30 minutes"). During illnesses, focus on small, consistent fluid intake – ice chips, frozen fruit pops, or soups can also help sneak in fluids if a child resists drinking.

Signs of Dehydration in Kids

It’s important to recognize the signs of dehydration in children so you can address the problem quickly. Early dehydration can often be reversed by prompt fluid intake, but if it progresses, it can become a medical emergency. Here are some warning signs to watch for:

• Reduced urine output: Fewer wet diapers in infants (fewer than ~6 per day) or infrequent trips to the bathroom in older kids can indicate dehydration. Also, dark yellow, concentrated urine (urine should be pale yellow or almost clear when a child is well-hydrated) is a red flag. If your child has not urinated at all in 6–8 hours (or has only a very small amount of dark urine), they are likely dehydrated.

• Dry mouth and lips: A parched, dry mouth or cracked lips are common signs of mild to moderate dehydration. You may notice your child’s tongue looks dry or sticky. Lack of tears when crying is another indicator – a well-hydrated baby or child should produce tears, so crying with few or no tears is concerning.

• Sunken soft spot (in infants): In babies, check the fontanelle (soft spot on the top of the head). A sunken soft spot is a sign the infant may be dehydrated. This, combined with dry mouth and few wet diapers, is a clear signal to seek medical advice and rehydrate the baby.

• Lethargy, low energy, or irritability: Dehydration can cause kids to act fatigued, play less than normal, or become unusually fussy or cranky. A dehydrated child might be dizzy, lightheaded, or just “out of sorts.” In mild dehydration they may just seem a bit more tired or irritable than usual. As it worsens, they can become very drowsy or difficult to rouse (excessive sleepiness).

• Sunken eyes and cool skin: In more severe dehydration, a child’s eyes may look sunken or hollow. Their skin might lose its normal elasticity – if you pinch the skin on the back of their hand gently, it may lack its usual bounce-back. Hands and feet might feel cool or even have a blotchy discoloration due to poor circulation. The skin may appear wrinkled or doughy in infants with severe dehydration.

• Rapid breathing or heart rate: As dehydration progresses, it can lead to a fast heart rate and quick, shallow breathing. The body is working harder to maintain blood flow with less fluid volume. If your child’s heart is racing or they are breathing faster than normal even while at rest, and it doesn’t improve after rehydrating, seek medical care.

• Other serious signs: In extreme cases or heat-related dehydration, symptoms like nausea and vomiting might occur (which worsen the dehydration), and the child may develop muscle cramps, headache, or confusion. If a child is dizzy to the point of nearly fainting, or complains of a severe headache, or is acting very strangely, these could be signs of severe dehydration or heat exhaustion. Such symptoms merit immediate medical attention.

If you notice signs of mild to moderate dehydration (dry mouth, low urine, etc.), begin rehydrating your child right away with water or an oral rehydration solution (for more severe cases). For infants, if you suspect dehydration, contact a pediatrician immediately. Infants can deteriorate quickly, so medical guidance is crucial – the doctor may direct you to give an electrolyte solution (like Pedialyte) or, in severe cases, the baby might need IV fluids. In older children, if symptoms don’t improve rapidly after drinking or if they show severe dehydration signs (very lethargic, no urine output, sunken eyes, etc.), seek medical care or emergency services. Dehydration can usually be treated effectively if caught early, so knowing the signs is vital.

Tips to Encourage Good Hydration Habits

Getting kids to drink enough water isn’t always easy – many children would rather have sweet juices or sodas, and some simply aren’t interested in plain water. Here are some parent-tested strategies to promote healthy hydration:

• Make water fun and tasty: Water doesn’t have to be boring! Try infusing water with slices of lemon, orange, berries, cucumber, or mint to add a hint of natural flavor and color. You can also freeze small pieces of fruit in ice cubes and toss those into water – it makes for a fun presentation that can entice kids to drink more. The whole family might find they drink more water when it’s “fruit-infused” or visually appealing.

• Offer water-rich foods: Many fruits and vegetables have a high water content and contribute to overall hydration. Keep these foods handy as snacks. Watermelon, cantaloupe, strawberries, oranges, grapes, and cucumbers are over 80–90% water and great choices. Serving a bowl of chilled watermelon or orange slices on a hot day, for instance, helps with hydration (and provides vitamins). Cold homemade fruit popsicles or 100% juice pops are another hydrating treat – you can blend fruit and a bit of yogurt to make your own freezer pops for a hot afternoon.

• Use special cups or bottles: Children get excited about new or personalized items. Encourage them to drink by giving them a fun water bottle or cup of their own. For younger kids, a cup with their favorite cartoon character or a silly straw can make drinking water more appealing. Older kids might like a trendy reusable bottle (add stickers or their name to personalize it). Having a water bottle they love can motivate them to carry it around and sip often. As a bonus, a reusable bottle allows you to easily track roughly how much they’ve had to drink that day.

• Set a schedule and reminders: Incorporate water drinking into your child’s routine. For example, make it a rule that they drink a glass of water first thing in the morning, with every meal and snack, and after playtime. If your child tends to forget, gentle reminders or fun prompts can help – some parents use smartphone alarms or colorful charts to remind kids to “take a sip.” During sports or outdoor play, enforce regular water breaks (every 15–20 minutes, have everyone pause for a drink). Over time, these routines can train kids to drink on their own before they get thirsty.

• Be a role model: Children learn by example. Let them see you choosing water as your main drink and carrying a water bottle when you go out. Make a habit of serving water at family meals. When kids observe their parents, teachers, or older siblings consistently drinking water, they will be more inclined to do the same. You can even make it a family challenge – for instance, have everyone in the family decorate a personal water bottle and aim to refill it X number of times per day.

• Limit sugary and caffeinated drinks: Reducing access to less healthy beverages will naturally encourage kids to drink water. The AAP recommends water and plain milk as the primary drinks for children. Sugary drinks like soda, sports drinks, fruit punches, and even 100% fruit juice in large amounts can spoil a child’s appetite and make them less likely to drink plain water. These drinks also contribute to excess calories and can increase the risk of weight gain and tooth decay. Set clear rules, such as no soda with meals or limiting juice to a small glass (4–6 ounces) per day for older kids (and none for infants under 1). By keeping sweet drinks as occasional treats instead of daily staples, children are more apt to turn to water when they’re thirsty.

Finally, keep in mind that building good hydration habits takes time. Positive reinforcement helps – praise your child when they choose water, or make a fun sticker chart to track each cup of water they drink. Educate them in simple terms about why drinking water is good (“Water helps your body stay cool when you play” or “It helps you not feel so tired”). Many kids respond well if you give them a bit of responsibility and choice, such as letting them pick out a new water bottle or choose which fruit to add to the water pitcher each day.

Conclusion

Water is truly the best drink for kids. Making sure your children drink enough water every day will keep them healthy, energetic, and focused. Use the age-by-age guidelines as a starting point for how much water kids should drink, but remember to adjust for hot days, sports, or sickness when extra hydration is needed. By learning to recognize dehydration signs and by fostering good hydration habits early – like making water readily available and even fun – parents and caregivers can help children stay safely hydrated. With a little encouragement and the right examples, kids can learn to listen to their bodies, drink when they’re thirsty (and even before thirst hits), and develop lifelong healthy hydration practices. Here’s to raising well-hydrated, happy kids!

Sources:

• World Health Organization (WHO) – Breastfeeding Q&A: confirms infants under 6 months get all needed fluids from breastmilk (no extra water).
• American Academy of Pediatrics – HealthyChildren.org: “Choose Water for Healthy Hydration” and related articles: provided age-based fluid recommendations, tips for encouraging water intake, and dehydration warning signs.
• European Food Safety Authority (EFSA) – Dietary Reference Values for water: outlined adequate daily total water intakes for children by age and sex (e.g. 1.3 L for 2–3 yrs, 1.6 L for 4–8 yrs, 1.9 L for girls 9–13, 2.1 L for boys 9–13).
• Academy of Nutrition and Dietetics – Kids’ Total Daily Water Requirements: noted U.S. Institute of Medicine guidelines (e.g. ~7 cups for 4–8 yrs, 9–10 cups for 9–13 yrs) and emphasized factors like climate and activity impact needs.
• Mayo Clinic – Dehydration in Children (2025): explained the importance of extra fluids during illness (vomiting/diarrhea) and in hot or active conditions; listed risk factors and prevention tips.
• St. Louis Children’s Hospital – “How much water does my child need?”: stressed that waiting for thirst is not enough and proactive hydration is necessary for active kids.
• American Academy of Pediatrics – Caring for Your Baby and Young Child: provided signs of dehydration in infants and children (e.g. few wet diapers, no tears, sunken eyes/fontanelle, lethargy).
• U.S. CDC – Nutrition and Health Fast Facts: highlighted that many children do not drink adequate water (average ~23 oz/day), underlining the need for improved hydration habits.