How much water should you drink a day?
Water makes up much of your body and is involved in almost everything it does. But how much do you really need?
The usual guidance
NHS advice is to drink about 6 to 8 glasses of fluid a day. That is roughly 1.2 to 2 litres, and it can include water, lower-fat milk, tea and coffee. Many people do not need to push beyond that.
Why it varies
Your needs depend on:
- Heat and humidity.
- Exercise and sweating.
- Body size.
- Pregnancy or breastfeeding, which need more.
- Illness, such as fever, vomiting or diarrhoea.
- Diet. You also get water from food, especially fruit and vegetables.
How to tell if you are drinking enough
Pale yellow or clear urine is a good sign. Dark urine, headaches, tiredness or a dry mouth can suggest you need more.
What counts
Water is best, but milk, tea, coffee and sugar-free drinks all count. Sugary drinks and fruit juice add calories, so limit them. Alcohol does not help hydration.
Can you drink too much?
Drinking huge amounts in a short time can be harmful. There is no benefit in forcing extra water, so drink to thirst, and a bit more when it is hot or you are active.
Water and appetite
Thirst can sometimes feel like hunger, and a drink before a meal might help some people eat a little less, but it is not a weight-loss trick.
Make it a habit
- Keep a bottle where you can see it.
- Have a glass with each meal.
- Add a slice of lemon or cucumber if you like flavour.
Track it
Older adults and young children
Older people often feel less thirsty and can become dehydrated more easily, so regular drinks through the day are a good habit. Young children need drinks regularly too, mostly water and milk, and need more in hot weather.
Drinking during exercise
For ordinary workouts, drinking to thirst is fine. In long or hot sessions you will need more, and sometimes salts and carbohydrate. Sipping regularly is better than gulping a lot at once.
Common questions
Does tea or coffee count? Yes. Caffeine has a mild effect on the body, but tea and coffee still contribute to your fluid intake. Very high caffeine intakes are not recommended, especially in pregnancy.
Does fruit juice count? It counts as fluid, but it is high in sugar, so the NHS advises limiting it to a small glass a day.
Do I need to drink more if I am dieting? Not specifically. Some people find thirst and hunger confusing, so a glass of water first can help.
What colour should my urine be? Pale straw is ideal. Some vitamins and foods change the colour, so use it as a guide, not a test.
Should I drink 2 litres exactly? Not necessarily. It is a useful reminder, but your needs vary from day to day.
Foodie has a simple water counter on the Today page: tap to add a glass (250 ml) and watch the day fill up, so you can see roughly where you are. Open Foodie.