The Benefits of Drinking Enough Water for Your Health

The short answer

There is no single perfect number. A good starting point is 6 to 8 glasses of fluid a day, and more when it is hot or you are active.

Thirst is a useful guide for most healthy people. Drink when you are thirsty, and add a glass with each meal.

The sections below explain the numbers and how to make them work in real life.

What the numbers say

Different sources measure different things, which is why numbers can look confusing.

Harvard notes that about 20 percent of our total water intake comes from food rather than drinks. That is why the total figure is higher than the NHS drink figure.

What counts toward your water

Plenty of things count, not just plain water.

• Water, of course.
• Milk and unsweetened milk alternatives.
• Tea and coffee.
• Water-rich foods such as cucumber, lettuce, berries and melon.
• Soups and stews.

Does coffee dehydrate you?

Not in normal amounts. Harvard says more than about 180 mg of caffeine a day, roughly two cups of brewed coffee, may make you urinate more for a short time, but it does not cause dehydration.

Keep an eye on your total caffeine, and avoid it late in the day if it affects your sleep.

What raises your water needs

• Hot weather. You lose more water through sweat.
• Exercise. Drink before, during and after longer sessions.
• Fever. Your body loses more fluid.
• Vomiting or diarrhea. Replace fluids and get medical advice if it lasts.
• Pregnancy and breastfeeding. Needs are higher, as the table shows.

Harvard lists fever, exercise, extreme temperatures and vomiting as common reasons to drink more.

Signs you may need more water

Harvard says even a small water deficit, about 2 percent, can affect you. Signs include:

• Tiredness.
• Trouble concentrating or memory lapses.
• Mood changes, such as feeling irritable.
• Dark yellow urine. Pale yellow is a common sign of good hydration.

Over time, not drinking enough is linked with problems such as constipation, urinary tract infections and kidney stones.

Ten easy habits to drink enough

1. Drink a glass of water when you wake up.
2. Keep a refillable bottle where you can see it.
3. Have a glass with each meal.
4. Set a reminder if you forget.
5. Add lemon, cucumber or mint if plain water feels boring.
6. Choose water-rich snacks, like fruit and vegetables.
7. Drink a glass before and after exercise.
8. Order water when eating out.
9. Track your drinks for three days to see your pattern.
10. Aim for a steady pace, not one huge glass at night.

Sugary drinks and alcohol

The WHO advises keeping free sugars under 10 percent of your daily energy. Soda, energy drinks and sweetened coffee drinks can add a lot fast.

Fruit juice has sugar too, so keep it to a small glass. If you drink alcohol, keep to the limits in your country's guidelines, and add water between drinks.

Can you drink too much water?

For most people, drinking to thirst is enough. There is no benefit in forcing large amounts.

Some medical conditions and medicines change how your body handles fluid. If you have one, follow your doctor's advice.

Water needs at different ages

Harvard, citing US guidance, also gives total water figures for children and teens. These include water from food as well as drinks.

Children and teens who play sports or spend time in the heat need more. Encourage a water bottle at school and at practice.

For babies and very young children, ask a pediatrician about fluids.

Water and exercise

You lose water through sweat when you exercise. Drinking enough helps you feel and perform better.

• Start a workout already well hydrated.
• Sip during longer or hotter sessions.
• Drink again afterward, especially if you sweated a lot.
• Choose water for most workouts, since it is all you need for short sessions.

Very long or intense exercise may call for more planning. A sports dietitian or coach can help.

Try a three-day water log

If you are not sure how much you drink, track it for three ordinary days. You will spot patterns fast.

Compare your total with the guidance above. Most people find one gap, often the afternoon, and can fix it with a bottle on the desk.

Do not obsess over the exact count. The aim is to notice, not to score yourself.

Flavor your water without adding sugar

If plain water feels dull, a little flavor can make it easier to drink more. You do not need sweetened drinks.

• Add slices of lemon, lime, orange or cucumber.
• Drop in a few mint leaves or a handful of berries.
• Try unsweetened herbal tea, hot or iced.
• Try sparkling water with a squeeze of citrus.
• Keep a jug in the fridge so it is always cold.

Replacing sugary drinks with water is one of the simplest changes you can make. The WHO advises keeping free sugars low, and drinks are an easy place to cut them.

Water at work, at school and on the go

Busy days make it easy to forget to drink. A few small tricks help.

• Keep a bottle on your desk and refill it at set times, such as each meeting.
• Carry a small bottle in your bag.
• Link drinking to habits you already have, such as after brushing your teeth.
• Ask for water when you order coffee or lunch.
• When traveling, carry an empty bottle through security and refill it.

If plain sips do not stick, try a small routine, such as a glass when you sit down at your desk and another before you leave.

Simple ways to drink more water

Knowing how much to drink is one thing. Doing it every day is another. These habits make it easier.

• Keep a refillable bottle on your desk or in your bag.
• Drink a glass when you wake up and another with each meal.
• Add lemon, cucumber or mint if plain water feels dull.
• Set a gentle reminder on your phone if you often forget.
• Have a drink of water before you reach for a snack, in case you are thirsty.

Use the color of your urine as a rough guide

Pale yellow usually suggests you are drinking enough. Darker urine can be a sign you need more fluid.

This is only a rough guide. Some foods, vitamins and medicines change color. Talk to your doctor if you notice anything unusual.

Water from food and other drinks

Fruit, vegetables, soups and milk all add to your fluid intake. Tea and coffee count too, though it makes sense to watch sugar and caffeine.

For a broader look at balanced meals, see our guide on how to build a balanced plate.

Adjust when life changes

You may need more fluid in hot weather, when you are active or when you are ill. Listen to your body and keep water handy.

If you have a health condition that affects fluid, follow your doctor's advice.

Common hydration myths

Myth 1: Everyone needs exactly the same amount

Needs depend on your size, activity, climate and health. Use general guidance as a starting point, not a strict target.

Myth 2: Only plain water counts

Other drinks and water-rich foods all add to your intake, though water is usually the healthiest choice.

Myth 3: More is always better

Drinking far more than you need does not add benefit, and in rare cases too much can be harmful. If you have a health condition, follow your doctor's advice.

For most healthy people, steady sips through the day and a drink with meals is enough.

Recap: your hydration plan in five points

• Aim for about 6 to 8 glasses of fluid a day.
• Remember that food supplies about 20 percent of your water.
• Drink more when it is hot, when you exercise or when you are unwell.
• Water, milk, tea and coffee all count.
• Limit sugary drinks and check with a doctor if you have a medical condition.

Water intake: frequently asked questions

Sources and further reading

We checked targets and thresholds against these sources. Figures are rounded, and examples are illustrations, not prescriptions.

• NHS: Water, drinks and nutrition
• Harvard T.H. Chan School of Public Health, The Nutrition Source: Water
• World Health Organization: Healthy diet fact sheet

Want more? Head back to the Nutrition hub, or read the Healthy Eating Guide.