How Much Water Should You Drink a Day?
UK guidance suggests 6 to 8 cups or glasses of fluid a day for most adults. European reference values put total water at about 2.0 litres a day for women and 2.5 litres for men, including the water in food. You need more when it is hot, when you are active, or when you are ill.
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Key takeaways
- Aim for 6 to 8 cups or glasses of fluid a day (NHS Eatwell Guide) as a starting point.
- EFSA's adequate total water intake is about 2.0 L a day for women and 2.5 L for men, including water from food.
- Water, lower-fat milk, and lower-sugar drinks including tea and coffee all count.
- Pale yellow urine is a simple sign you are drinking enough.
On this page
The short answer
For most healthy adults, the NHS suggests 6 to 8 cups or glasses of fluid a day. Reference values from health authorities are a little higher because they include the water you get from food:
| Reference | Women | Men | Includes food? |
|---|---|---|---|
| EFSA (Europe, 2010) | 2.0 L/day | 2.5 L/day | Yes, total water |
| National Academies (US, 2005) | 2.7 L/day | 3.7 L/day | Yes, total water |
These are adequate intakes for populations, not exact targets for each person. Food usually provides around a fifth of total water, so EFSA's values work out at roughly 1.6–2.0 litres from drinks a day. Our water intake guide shows the values for your situation.
Why "8 glasses a day" is only a rough guide
How much you need depends on your body size, how active you are, the climate, what you eat, and your health. Rather than counting glasses exactly, the NHS suggests a simple check: aim to drink enough during the day that your pee is a clear, pale yellow colour.
When you need more
The NHS notes you may need more fluid if you are:
- pregnant or breastfeeding
- in a hot environment
- physically active for long periods
- ill or recovering from illness, especially with fever, vomiting or diarrhoea
Which drinks count
- Water is the healthiest, cheapest choice.
- Lower-fat milk and unsweetened plant-based drinks.
- Tea and coffee count too. Keep caffeine moderate.
- Fruit juice and smoothies contain sugar. The NHS suggests limiting them to one small glass (150 ml) a day, with a meal.
Go easy on sugary drinks
Sugary soft drinks, energy drinks and sweetened juices add sugar and calories without making you feel full, and the sugar can damage teeth. Swapping them for water, sparkling water, or diet and no-added-sugar drinks is one of the simplest healthy changes you can make.
Easy ways to drink more water
- Keep a refillable water bottle with you.
- Have a glass of water with each meal.
- Add a slice of lemon, lime or cucumber if you don't like plain water.
- Drink regularly through the day rather than a lot at once.
When to be careful
Some people with heart, kidney or liver conditions are told to limit how much they drink. If that applies to you, follow your doctor's advice rather than general guidance. Seek medical advice for signs of dehydration that don't improve with drinking, such as dizziness, confusion or very little urine.
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Watch on YouTube (opens in a new tab)Common questions
Do tea and coffee count towards my fluid intake?
Yes. The NHS says water, lower-fat milk and lower-sugar drinks, including tea and coffee, all count. Keep caffeine moderate; if you are pregnant, the NHS advises no more than 200 mg of caffeine a day.
Can you drink too much water?
Yes, although it is rare in healthy people. Drinking very large amounts in a short time can dilute the sodium in your blood. Some people with heart, kidney or liver conditions are advised to limit fluids, so follow your doctor's advice.
Sources
- Water, drinks and hydration (opens in a new tab) — NHS
- Scientific Opinion on Dietary Reference Values for water (opens in a new tab) — European Food Safety Authority (EFSA), 2010
- Dietary Reference Intakes for Water, Potassium, Sodium, Chloride, and Sulfate (opens in a new tab) — National Academies of Sciences, Engineering, and Medicine, 2005
- About Water and Healthier Drinks (opens in a new tab) — Centers for Disease Control and Prevention (CDC)