01 Oct 2020

70% of your body is made up of water, therefore it is essential you drink enough to keep your body in working order. Water makes up your blood, it keeps your heart pumping, and your brain working. It is also essential in allowing us to keep a comfortable body temperature through sweating, and helps us remove waste through our pee.

What happens if I don’t drink enough?

Keeping hydrated by drinking enough is vital for good health. If you become dehydrated it can start to cause a lack of concentration, headaches, tiredness, dizziness, lightheadedness and confusion. If you are dehydrated for a long time it can start affecting your kidney function, which will then affect your bodies ability to remove waste products. This can cause you to experience problems like kidney stones, urinary tract infections, and chronic renal disease.

How do I know if I’m drinking enough?

It is important for you to listen to your body. If you feel thirsty it is important to have a drink, as this is your body's way of telling you that you need fluid. Taking note of the colour of your pee is also a good way to check how hydrated you are. Children and older adults often don’t feel thirst so checking pee colour can be an easy way for everyone to find out if their water needs are being met or not.

Our pee should be pale straw colour or clear. If our pee is dark yellow or orange we need to drink more. If our pee is dark orange or brown, we are severely dehydrated and drinking plenty of fluid is essential to restore our dehydration.

How much do I need to drink?

Everyone will need different amounts of fluid. This is why checking your pee is so important, as this is a way of monitoring your hydration so you can personalise your fluid needs as you need to. Lots of things affect how much fluid we need, including the weather and temperature, how much exercise you do and how much you naturally sweat. The hotter the temperature, the more exercise you do and the more you sweat, the more you need to drink.

Typically, the average adult needs between 1.5 to two litres of fluid a day. This is the equivalent to around 6-8 mugs of fluid. The following table provides more detail on fluid requirements for different people and age ranges

Recommended adequate intakes of water from drinks



Adequate fluid intake from drinks (ml/day)


0-6 months

7-12 months

550ml through milk

640 – 800ml


1-2 years

2-3 years

4-8 years

9-13 years


> 14 years

880 – 960ml



Boys: 1680ml

Girls: 1520ml

As adults

Adults (including older adults)


Men: 2000ml

Women: 1600ml

Pregnant women


As adults + 300ml per day

Lactating women


As adults + 600-700ml per day

Common household measures include: 

1 medium size glass ≈ 200 ml
1 can of fizzy drink ≈ 330 ml
1 mug ≈ 250 ml
1 cup ≈ 200 ml 

What type of drinks should I have?

Drinking water is the easiest way to get enough fluid. Tap water is safe to drink in the UK, so getting access to water is cheap and easy. You can add sugar free squash to flavour, or add slices of fruit to make it more interesting. 

If you like fizzy drinks you can buy sparkling water from the shops and add sugar free squash too to make a refreshing drink. Sugar free fizzy drinks do count towards your fluid, though these, like full sugar fizzy drinks, can affect our teeth if we drink them in large quantities. 

Fruit juice also makes a nutritious drink. Fruit juice contains vitamins, minerals and fibre. Having one 200ml glass a day will count towards one of your 5-a-day. Fruit juice is also high in sugar, therefore be mindful of this dependant on your health goals.

Milk (cold or warm) counts as fluid too and drinking milk can be a good way of introducing more calcium to your diet. Depending on your health goals consider what type of milk you choose. If you are wanting to gain weight choose full fat milk (blue top), and if you are wanting to manage your weight choose skimmed-milk (red top).

Tea and coffee can be another good way of staying well hydrated. However, if you drink a lot of tea and coffee you should be aware of the amount of caffeine you are consuming. This is particularly important for pregnant women.

Alcohol does not count towards your daily fluid needs. It may make you pee more than usual, so if you choose to drink alcohol it’s a good idea to alternate with water or sugar free fizzy drinks. We would encourage you to be mindful of guidelines for drinking alcohol. Read our Food Fact Sheet on Alcohol Facts to find out more.


Children don’t recognise thirst like adults do. Also younger children can’t ask for a drink or say they are thirsty, so children are particularly at risk of dehydration.

Having enough fluid at school and toilet breaks can also be a problem. It is important that children drink frequently throughout the day. Sending your child to school with a water bottle can be a good way to encourage them to drink more. There is some evidence that children who drink extra water perform better in attention and memory tests.

Older adults

Older adults are at risk of dehydration and may have difficulties accessing drinks. Fear of incontinence may also mean that some older adults reduce their fluid intake.

Regular drinks should be encouraged; tea and coffee are a good way of getting older adults to drink. Older adults who are dehydrated are at particular risk of urine infections and falls, therefore should monitor how much they drink in hot weather.


It is important that water lost through sweat when exercising is replaced to maintain performance and health. Some athletes may find isotonic drinks useful. To find out more about fluid, nutrition and sport read our Food Fact Sheet on Sport and Exercise.


Having regular drinks throughout the day will help you stay well hydrated especially when it is hot or you are exercising. Keep an eye on the colour of your pee; if it dark you need to drink more. Children and older adults are more at risk to dehydration and may need to be encouraged to drink more.