Why is water important for good health?

Water is an essential part of a healthy balanced diet. Over half of the human body is made up of water. We need water to:

• digest food and to absorb nutrients
• move our bodies well
• get rid of waste products
• keep our body at the right temperature

Drinking water also keeps your teeth and mouth healthy.

In most parts of Australia, the tap water contains fluoride. This helps to protect against tooth decay.

Water is also needed for the body to make saliva. You need saliva to wash food away from your teeth. Saliva also helps you:

• chew
• taste
• swallow

What is dehydration?

Dehydration happens when your body doesn't have enough water. Being dehydrated can affect your physical and mental performance. Your body does not work as well if it is dehydrated.

People who don't drink enough water every day are at greater risk of problems such as:

• kidney stones
• constipation
• urinary tract infections
• headaches

How much water should I drink?

The amount of water that you should drink varies greatly from person to person. It depends on:

• what you eat
• your age
• what the temperature is
• whether you have a medical condition
• how your metabolism works
• if you are exercising

There is no strict amount of water you should drink each day. It's especially important for children and older people to drink enough water.

As a general rule:

• males need about 10 cups (2.6 litres or 2600mL) of fluids every day
• females need about 8 cups (2.1 litres or 2100mL) of fluids a day — add another cup a day if you're pregnant or breastfeeding
• children need about 4 to 5 cups of fluids a day
• teenagers need 6 to 8 cups of fluids a day

In Australia, 1 cup is about 250mL. It is the same size cup that is used in cooking.

Where does my body get water from?

We get about one fifth of the water we need from food, the rest comes from liquids that we drink. You can get water from any fluids — including tea and coffee, fruit juice, milk, soup and soft drinks.

The amount of water you need can change from day to day depending on what you are doing. If it's a hot or humid day, you might also need more water.

You should be careful how much fruit juice, cordial and soft drinks you drink. They can make you put on weight and damage your teeth.

How does my body get rid of water?

Your body gets rid of water throughout the day through:

• breathing
• sweating
• urinating (doing a wee)

How can I stay hydrated?

To stay hydrated, it's important to drink before you feel thirsty. This is especially important if you are exercising or if it's a hot day. Even if you're not thirsty, try to drink water regularly throughout the day.

Australian tap water is a good choice for staying hydrated. The fluoride in tap water is also important for healthy teeth. Tap water is safe and checked by health authorities.

At times you might be advised by health authorities to drink bottled or boiled water. This could be due to an incident that affects the quality of the water, such as a flood or the discovery of bacteria in the water supply.

What happens when you don't drink enough water?

Not drinking enough water can make you very ill. Severe dehydration can lead to dizziness and collapse.

If you are showing any signs of dehydration, drink some water straight away. Seek medical advice if you still don't feel better.

Older people are at greater risk of dehydration because they naturally feel less thirsty. Their kidneys may also not work as well. Memory problems and not being very mobile can make it harder to stay hydrated. Certain types of medicines such as diuretics and laxatives can also lead to dehydration.

For older people, not drinking enough water over a long period of time can lead to problems such as constipation and confusion.

Signs that you are dehydrated and need to drink more water include:

• feeling thirsty
• dark coloured urine
• headaches
• dry skin, tongue and mouth
• tiredness
• irritability
• light headedness or fainting

Dehydration in babies and children can be serious and needs immediate medical attention.

What if I don't enjoy drinking water?

You can vary the taste of plain tap water by:

• keeping water in the refrigerator so it is cool and refreshing
• adding some berries, lemon slices or other fruit for a change in flavour

You could also try:

• sparkling water (not soft drink)
• herbal teas

You could look also for some recipes for iced tea, but avoid iced tea with added sugar as a regular drink.

Also, remember that plastic bottles used for bottled water are not good for the environment.

Is it possible to drink too much water?

Drinking too much water can lead to a dangerous condition called hyponatremia. When this happens, the levels of sodium in your blood become too diluted.

This can sometimes happen when people drink too much while doing intense physical activity, such as running a marathon. Babies can also have too much water if their formula is too diluted.

People with chronic kidney disease, heart failure or liver disease cannot get rid of water from the body as efficiently. If you have these conditions, it's a good idea to talk to your doctor about how much water to drink.

If you have another long-term medical condition, it's a good idea to talk to your doctor about how much water you need.

Resources and support

You can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.