How Much Water Should You Drink a Day? The 2026 UK Guide

How much water should you drink a day? It is one of the most searched health questions in the UK, and the answer is surprisingly simple. The NHS recommends six to eight glasses of fluid per day, which works out to approximately 1.5 to 2 litres. That includes all fluids, not just plain water.

But the simple answer does not tell the whole story. Your ideal intake depends on your weight, activity level, the weather, your diet, and whether you are pregnant or breastfeeding. In this guide, we break down the official UK guidelines, explain the factors that affect your personal needs, and share practical tips for actually hitting your target every day.

For a deeper look at the health benefits of staying hydrated, see our benefits of drinking water guide. If you are worried you might not be drinking enough, our companion article on signs of dehydration covers the warning symptoms to watch for.

NHS Guidelines for Daily Water Intake

The NHS Eatwell Guide recommends that adults in the UK drink six to eight glasses of fluid per day. A glass is approximately 200ml, which gives a range of 1.2 to 1.6 litres. However, the NHS also notes that you may need more in hot weather or during physical activity.

Importantly, these six to eight glasses include all fluids, not just plain water. Tea, coffee, milk, sugar-free drinks and even the water in food all count towards your daily total. However, water is the healthiest and most effective hydration choice because it contains zero calories, zero sugar and no additives.

The European Food Safety Authority (EFSA) recommends slightly higher figures: 2 litres per day for women and 2.5 litres per day for men, including water from food. Since food typically provides around 20% of your fluid intake, this translates to roughly 1.6 litres of drinks for women and 2 litres for men.

Factors That Affect How Much You Need

Body Weight

Larger bodies contain more water and require more to stay hydrated. A common rule of thumb is to drink 30 to 35ml per kilogram of body weight per day. For a 70kg person, that works out to 2.1 to 2.5 litres. For a 55kg person, it is 1.65 to 1.9 litres. This is a guideline, not a precise prescription, but it gives you a personalised starting point.

Climate and Season

During UK summers, particularly during heatwaves, you lose more water through sweating and need to drink more to compensate. Heated indoor environments in winter also cause fluid loss through dry air. As a general rule, add an extra 500ml per day during hot weather or when spending time in heated, air-conditioned environments.

Pregnancy and Breastfeeding

The NHS recommends that pregnant women drink slightly more than the standard guidelines, and breastfeeding mothers should increase their intake further to support milk production. An additional 300ml per day during pregnancy and 700ml per day while breastfeeding is a reasonable starting point, but speak to your midwife or GP for personalised advice.

Diet

If your diet is rich in fruits and vegetables, you are already getting a significant amount of water from food. Cucumbers, watermelon, oranges and lettuce are all over 90% water by weight. A diet high in processed or salty foods, on the other hand, increases your need for additional water to help your kidneys process the excess sodium.

Water Intake for Exercise

Exercise increases your water needs significantly. The general recommendation is to drink an additional 500ml to 1 litre per hour of moderate to intense exercise, depending on the intensity and how much you sweat.

• Before exercise: Drink 500ml in the two hours before your workout. This ensures you start hydrated.
• During exercise: Sip 150 to 250ml every 15 to 20 minutes. A straw bottle makes this easier without interrupting your workout.
• After exercise: Drink 500ml to 750ml within 30 minutes of finishing. If you sweated heavily, add electrolytes or a pinch of sea salt.

For hot yoga, outdoor running in summer, or any activity lasting more than 90 minutes, increase these amounts. The ProWorks Explorer 2L is ideal for long sessions where you need more capacity. For shorter gym sessions, a 1 litre bottle is typically sufficient. See our sports water bottle guide for exercise-specific recommendations.

How Much Water by Age Group

Children (4 to 13 years)

The NHS recommends that children aged four to eight drink approximately 1 to 1.2 litres per day, and children aged nine to thirteen should drink 1.2 to 1.6 litres. A school water bottle helps children build regular drinking habits.

Teenagers (14 to 18 years)

Teenagers should aim for adult-level intake: approximately 1.5 to 2 litres per day from drinks alone. Active teenagers involved in sport may need more, particularly during training and competition days.

Adults (19 to 64 years)

The standard recommendation of 1.5 to 2 litres per day applies. Adjust upwards for exercise, hot weather, pregnancy or breastfeeding as outlined above.

Older Adults (65+)

Dehydration risk increases with age because the sensation of thirst diminishes. Older adults should make a conscious effort to drink regularly throughout the day, even when they do not feel thirsty. Keeping a water bottle visible and within reach is one of the most effective strategies. For more on dehydration risks, see our signs of dehydration guide.

Simple Ways to Track Your Intake

Knowing how much to drink is one thing. Actually doing it is another. Here are practical strategies that make it easier to hit your daily target.

• Use a measured bottle: A 1 litre bottle gives you a clear, visual target. Finish one by lunch and one by evening, and you have hit 2 litres. The time-marked bottle guide has options with built-in tracking.
• Drink before meals: Having a glass of water before each meal adds 600ml to your daily total without any conscious effort.
• Keep a bottle visible: Out of sight means out of mind. A bottle on your desk or kitchen worktop is a constant visual reminder to drink.
• Set reminders: If you struggle to remember, set a phone reminder every two hours to take a drink.
• Front-load your morning: Drink 500ml first thing in the morning to start the day hydrated. Your body loses water overnight through breathing and sweating, so morning hydration is particularly important.

For bottle size guidance, our water bottle size guide helps you choose the right capacity for your daily routine.

Common Hydration Myths

Myth: You need exactly eight glasses a day

The "eight glasses" rule is a simplification. Your actual needs depend on your body weight, activity level, climate and diet. The NHS range of six to eight glasses is a useful starting point, but it is not a fixed rule. Some people need more, some need less. Listen to your body and use the colour of your urine as a guide: pale straw is well-hydrated, dark yellow means you need to drink more.

Myth: Tea and coffee do not count

They absolutely do. While caffeine has a mild diuretic effect, the water content in tea and coffee far outweighs any fluid loss from the caffeine. The NHS explicitly includes tea and coffee as part of your six to eight daily glasses. Just avoid adding too much sugar.

Myth: You can never drink too much water

Overhydration is rare but real. Drinking excessive amounts of water in a short period can dilute the sodium in your blood, a condition called hyponatraemia. This is most common during intense endurance exercise. For daily life, it is almost impossible to overhydrate if you simply drink when you are thirsty and aim for the recommended guidelines.

Myth: Cold water is better than room temperature

Your body absorbs water at any temperature. Cold water may feel more refreshing, particularly during exercise, and some research suggests it is absorbed marginally faster. But room temperature water is equally effective for hydration. Drink whichever you prefer. An insulated bottle keeps your water at your preferred temperature all day.