How much water to drink a day

One person says two litres, another says eight glasses, a third says “drink until you're bored”. Here's the deal: there's no single exact number, but there's a clear guide and a few simple signs that you're getting enough.

Information checked on 2026-09-30. General information, not medical advice. How we calculate

In short: the European Food Safety Authority (EFSA) gives adults about 2 litres of fluid a day for women and about 2.5 litres for men – in total, food included. You usually need to drink less than that looks like.

Where 2 and 2.5 litres come from

EFSA sets an “adequate intake”: a guide, not a strict rule. For adult women it's about 2.0 litres and for adult men about 2.5 litres of total water a day. That includes not just the glass of water but also tea, coffee, soup, milk, fruit, vegetables and all other food. Roughly a fifth of the fluid typically comes from food, so what you need to drink is less than the full 2–2.5 litres.

Needs are higher in pregnancy and breastfeeding, and different for children. This guide is for adults; if you're pregnant or breastfeeding, check with your doctor or midwife.

How to tell if you're drinking enough

  • Urine colour. Pale straw yellow is usually a good sign. Dark amber suggests you could drink more (though some vitamins and medicines change the colour).
  • Thirst. For a healthy adult it's usually a good guide. Feel thirsty? Have a drink.
  • How you feel. Dry lips, a headache, tiredness or trouble concentrating can mean you need fluid, but they can also mean a hundred other things.

When you need more

  • on a hot day or in a sauna;
  • when you exercise or walk a lot – sweat carries fluid away;
  • when you're ill with a fever, vomiting or diarrhoea;
  • on a flight or in a room with dry heated air.

For older adults the feeling of thirst is often weaker, so it's easy to fall short. If someone close to you drinks little, a simple habit helps: a glass with every meal and one in between. More in our guide to nutrition for seniors.

What counts and what doesn't

  • Counts: water, tea, coffee, unsweetened milk, soups, fruit and vegetables (especially cucumber, watermelon and tomatoes).
  • Counts, but with calories: juice, fizzy drinks, sweetened coffee. They give fluid but also a lot of sugar – you don't feel them like a meal, and they add calories.
  • Doesn't count: alcohol. It pushes your fluid balance the wrong way.

5 easy ways to drink more often

  1. Start the day with a glass of water before your coffee.
  2. Keep a bottle where you sit – on your desk or next to the sofa.
  3. Tie a drink to a habit: took your tablets, sat down at the computer – have a drink.
  4. Don't like plain water? Add a slice of lemon, cucumber or mint. It adds no calories worth counting.
  5. Swap one sugary drink a day for water – a win for both fluids and calories.

When to talk to a doctor

Check with your doctor about how much to drink first if you:

  • have kidney or heart disease, or a doctor has limited your fluids;
  • take water tablets (diuretics) or other medicines that affect your fluid balance;
  • are very thirsty and pass urine very often (this can also be a sign of diabetes);
  • are losing fluid through long vomiting or diarrhoea and can't keep drinks down.

This is general information, not medical advice. If you have urgent symptoms (confusion, fainting, very little urine), call your local emergency number.

Want to see your day? The Dumpli app has water tracking: you log your glasses and watch a ring fill towards a daily goal (reminders are optional). The app is still being tested and works by invitation – you're welcome to join the waiting list. Not for you? Drinking by thirst is perfectly fine too. See the app → · Nutrition quiz

Frequently asked questions

Do I really need 8 glasses of water a day?

It's a popular rule of thumb (about 1.9 litres), not a precise scientific requirement. Your need depends on your weight, the weather, how much you move and what you eat. Going by thirst and urine colour works better than counting glasses.

Do coffee and tea count towards my water?

Yes. Coffee and tea are mostly water, and a moderate amount doesn't wreck your fluid balance. Don't count alcohol: it makes you lose fluid faster.

Can you drink too much water?

You can, but it's rare in healthy people. Trouble starts when someone drinks a very large amount in a short time (several litres within an hour, say) or when a doctor has limited their fluids. Sip through the day and listen to your body.

Does drinking water help you lose weight?

Indirectly it can: water has no calories, so it replaces sugary drinks. But water doesn't burn fat by itself, and there's no magic amount.

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