How Much Water Should a Child Drink Each Day?

Why Water Matters for Children

As a paediatric nutritionist, one of the questions I hear most often from parents is: how much water should my child drink each day? It seems straightforward, yet many families I work with in my Bristol clinic are surprised to learn that their children are not drinking nearly enough. Water is absolutely essential for a child’s body to function properly, and even mild dehydration can affect their concentration, mood and energy levels throughout the day.

A child’s body is made up of roughly 60% water, and because children are smaller and have a higher metabolic rate relative to their body weight, they can become dehydrated more quickly than adults. Water plays a critical role in almost every bodily process: it helps regulate body temperature, transports nutrients to cells, cushions joints, supports digestion and helps the kidneys flush out waste products. Without adequate fluids, even everyday tasks like paying attention in class or running around at break time become harder for children.

What many parents do not realise is that thirst is actually a late sign of dehydration. By the time your child says they are thirsty, their body is already mildly dehydrated. This is why building regular drinking habits, rather than waiting for children to ask for a drink, is so important. Good hydration also supports healthy bowel movements and helps prevent constipation, which is one of the most common childhood complaints I see in practice.

How Much Water Should a Child Drink by Age?

The amount of fluid a child needs each day depends on their age, size, activity level and the weather. The guidelines below are based on recommendations from the European Food Safety Authority (EFSA) and are consistent with NHS guidance on water and hydration. These figures refer to total fluid intake, which includes water, milk, and fluids from food.

It is worth noting that roughly 20% of daily fluid intake typically comes from food rather than drinks. Foods with a high water content, such as cucumbers, watermelon, oranges, tomatoes, soups and yoghurt, all contribute to your child’s hydration. So if your child eats plenty of fruits and vegetables, they will be getting a helpful amount of water from their diet alone.

For babies under six months who are exclusively breastfed or formula-fed, additional water is not needed. Breast milk and formula provide all the hydration a young baby requires. Once you begin introducing solid foods around six months, you can start offering small sips of water from an open cup or free-flow beaker with meals.

For toddlers aged 1 to 3, I recommend aiming for around 6 to 8 drinks per day, including milk feeds. Water should gradually become the main drink as your child moves towards their second birthday. By the time children start school, water and plain milk should be the primary drinks offered throughout the day.

Signs of Dehydration in Children

Recognising the early signs of dehydration can help you act before it becomes a problem. In my experience, many parents only think about dehydration during hot weather or when a child is unwell, but it can happen at any time of year, particularly during busy school days when children simply forget to drink.

The simplest way to check your child’s hydration is by looking at the colour of their urine. Pale straw-coloured urine generally indicates good hydration, while dark yellow or amber-coloured urine suggests your child needs to drink more. Here are the key signs to watch for:

• Dark yellow urine or strong-smelling urine
• Passing urine fewer than 4 times a day
• Dry lips and mouth
• Feeling tired, irritable or dizzy
• Headaches, particularly in the afternoon
• Difficulty concentrating at school
• Constipation or hard, dry stools

Research published in the British Journal of Nutrition has shown that even 1% to 2% dehydration can impair cognitive performance in children, affecting their memory, attention span and arithmetic ability. This is why many schools now encourage children to have a water bottle on their desk, and I strongly support this approach.

More serious dehydration, which can occur during illness with vomiting or diarrhoea, may cause sunken eyes, fewer wet nappies in babies, cold or mottled hands and feet, or unusual drowsiness. If you notice these signs, seek medical advice promptly. The NHS provides detailed guidance on when to seek help for dehydration.

Best Drinks for Children

When it comes to choosing the best drinks for children, I always tell families to keep it simple. Water and plain milk are the gold standard, and everything else is secondary. Here is my breakdown of the best options:

Water

Water is, without question, the best drink for children of any age. It contains no sugar, no calories and no additives. Tap water in the UK is safe, well-regulated and contains fluoride in many areas, which supports dental health. Encouraging your child to drink water from an early age sets a healthy habit that will serve them for life.

Plain milk

Whole milk is recommended for children aged 1 to 2, and semi-skimmed milk can be introduced from age 2 if your child is eating well and growing normally. Milk provides important calcium, protein, B vitamins and iodine. I generally recommend around 300 ml to 400 ml of milk per day for children over one year. More than this can reduce appetite for other foods and may contribute to excess calorie intake.

Water-rich foods

As I mentioned, foods with high water content contribute meaningfully to hydration. Soups, stews, fruits like strawberries and melon, and vegetables like cucumber and lettuce all help. Offering healthy snacks that include water-rich foods is a practical way to boost your child’s fluid intake without relying solely on drinks.

Drinks to Limit or Avoid

Many parents are surprised by how much sugar is hidden in drinks that are marketed as “healthy” or “natural” for children. In my clinic, I frequently see families who have unknowingly been giving their children significant amounts of sugar through drinks alone. The UK Soft Drinks Industry Levy has helped reduce sugar in some products, but many drinks remain problematic.

Fruit juice

Even 100% pure fruit juice contains a lot of natural sugar and virtually no fibre. The NHS recommends that if you do give fruit juice, it should be diluted at least 1 part juice to 10 parts water and limited to no more than 150 ml per day, served only at mealtimes to protect teeth. Many parents are shocked when I point out that a standard 200 ml carton of apple juice contains roughly 5 teaspoons of sugar.

Squash and cordial

Both sugar-sweetened and artificially sweetened squashes should be limited. While sugar-free versions are better for teeth, they still encourage a preference for sweet-tasting drinks, which can make it harder for children to accept plain water. If you do use squash, dilute it as much as possible.

Fizzy drinks

Carbonated drinks, whether sugary or diet, are best avoided entirely for children. They are acidic and can damage tooth enamel, and sugary versions contribute significantly to excess calorie intake. This includes cola, lemonade, energy drinks and sparkling flavoured waters with added sugar.

Energy and sports drinks

These are entirely unsuitable for children. Energy drinks contain high levels of caffeine and sugar, and sports drinks are unnecessary unless a child is engaged in prolonged, intense physical activity lasting over 60 minutes. For most children doing normal everyday physical activity, water is all they need.

Flavoured milks and smoothies

Flavoured milks, milkshakes and smoothies often contain added sugar or high levels of natural sugar. While they do provide nutrients, the sugar content means they should be treated as occasional foods rather than everyday drinks. A shop-bought smoothie can contain as much sugar as a fizzy drink. Understanding how ultra-processed food and drink affects children’s health can help you make better choices at the supermarket.

Practical Tips to Help Children Drink More Water

Getting children to drink enough water can feel like a daily battle, but in my experience, a few simple strategies can make a real difference. Here are my tried-and-tested tips from over 15 years of working with families:

1. Make water easily accessible. Keep a filled water bottle within your child’s reach at all times, whether at home, in the car or at school. Children are far more likely to drink when they do not have to ask for it. Invest in a reusable bottle with clear measurements so you can both track intake throughout the day.

2. Offer water at regular intervals. Rather than waiting for your child to ask for a drink, build water breaks into their routine: first thing in the morning, with each meal, after school, after physical activity and before bed. I recommend aiming for at least 6 to 8 opportunities to drink across the day.

3. Add natural flavour. If your child resists plain water, try adding slices of cucumber, lemon, orange, strawberry or a sprig of mint. Frozen fruit cubes can also make water more appealing. This is a much better option than reaching for squash or juice.

4. Lead by example. Children learn drinking habits from their parents. If you drink water regularly throughout the day, your child is more likely to follow suit. Make water the default drink at family mealtimes and keep a jug on the table.

5. Let them choose their own bottle or cup. Giving children some autonomy over their drinking equipment, whether it is a favourite colour, character or style of bottle, can increase their willingness to use it. For younger children, an open cup helps develop drinking skills.

6. Use visual cues. For younger children, a simple sticker chart tracking glasses of water per day can be motivating. Some families I work with use a water bottle with time markings on the side, which helps older children pace their intake across the school day.

7. Serve water-rich foods. On days when your child simply will not drink enough, compensate by offering foods with high water content at meals and snack times. Cucumber sticks, melon slices, grapes and soup are all excellent choices.

8. Avoid using sweet drinks as rewards. Offering juice or fizzy drinks as treats can create unhealthy associations and make plain water seem boring by comparison. This is particularly important when considering emotional eating patterns and reward-based food behaviours in children.

Water and Your Child’s Weight

There is a well-established link between what children drink and their weight. Sugary drinks are one of the largest single sources of added sugar in children’s diets, and they contribute calories without providing satiety, meaning children do not eat less to compensate. Research consistently shows that children who regularly consume sugary drinks are at a higher risk of overweight and obesity.

Replacing sugary drinks with water is one of the simplest and most effective changes a family can make. A study published in Pediatrics found that children who drank an extra glass of water per day consumed approximately 100 fewer calories from sugary beverages. Over time, these small changes add up significantly.

If you are concerned about your child’s weight, checking their hydration is a good starting point. Sometimes what appears to be hunger is actually thirst, and offering water before meals can help children recognise the difference. You can use a BMI calculator for children to check whether your child is in a healthy weight range, and understanding UK weight centile charts can help put the numbers in context.

Good hydration also supports better sleep quality, which in turn has a positive effect on appetite regulation and healthy weight maintenance. When children sleep well and stay hydrated, they are less likely to reach for high-calorie comfort foods during the day.

Special Circumstances: When Children Need More Water

While the daily guidelines I have outlined above are a solid starting point, there are several situations where your child will need more fluid than usual:

Hot weather

During warm summer days, children lose more water through sweat and need to increase their fluid intake. On hot days, I advise parents to offer water every 20 to 30 minutes during outdoor play, even if your child says they are not thirsty. A frozen water bottle can provide refreshment and encourage regular sipping.

Physical activity

Active children need more water to replace fluid lost through sweat. For most childhood activities, including PE lessons, playground games, swimming and after-school clubs, plain water is the best choice. Encourage your child to drink before, during and after exercise. A good rule of thumb is an extra 100 ml to 200 ml for every 30 minutes of vigorous activity.

Illness

When children have a fever, diarrhoea or vomiting, they lose fluids rapidly and are at higher risk of dehydration. During illness, offer small, frequent sips of water. For significant fluid loss, oral rehydration solutions (available from pharmacies) may be recommended by your GP. The NHS advises seeking medical help if your child shows signs of dehydration during illness.

Central heating and dry environments

During winter, central heating can dry out indoor air, and children may not feel as thirsty despite still needing adequate fluids. Maintaining regular drinking habits year-round is important, not just during warmer months.

Children with specific health needs

Some children may need more or less fluid than standard guidelines suggest. Children with certain medical conditions, those taking specific medications, or children with ADHD who may be on medication that affects appetite and thirst should have their fluid intake discussed with their GP or paediatrician. Children who experience recurrent constipation often benefit from deliberately increasing their water intake alongside dietary fibre.

Key Points to Remember

Helping your child develop good hydration habits now will benefit their health for years to come. As with so many aspects of childhood health and weight management, small, consistent changes are far more effective than dramatic overhauls. Start by making water the default drink in your home, keep it accessible, and lead by example. If you have concerns about your child’s fluid intake or hydration, speak to your GP, health visitor or a registered paediatric nutritionist for tailored advice.