Drinking water and your 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.

Your body also needs water to make saliva. You need saliva to wash food away from your teeth. Saliva also helps you:

• chew
• taste
• swallow

There is no strict amount of water you should drink each day.

The amount of water a person should drink depends on many things. It can also change from day to day depending on what you are doing.

It depends on:

• what you eat — food also contains water
• your age — adults need more water than children
• what the temperature is — you need more water on a hot or humid day
• whether you have a medical condition
• how your metabolism works
• if you are exercising or doing other physical activity

It's especially important for children and older people (Opens in new tab) to drink enough water.

As a general guide:

• 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. This is the same size cup that is used in cooking.

About one fifth of the water we need comes from food. The rest comes from liquids that we drink. You can get water from any fluids, including:

• fruit juice
• milk
• soup
• soft drinks
• tea and coffee

Water is the best thing to drink. 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.

Tea and coffee also contain caffeine, which can make you lose more water in your urine.

Read about discretionary drink choices (Opens in new tab).

Your body gets rid of water throughout the day through:

• breathing
• sweating
• urinating (doing a wee)

In Australia, you can get good quality drinking water from the tap. There are strict guidelines (Opens in new tab) for the safety of drinking water.

Australian tap water is checked for safety by health authorities. They monitor for contaminants such as chemicals, bacteria and parasites.

PFAS

Per- and polyfluoroalkyl substances (PFAS) are chemicals that have been used for many decades to make heat and stain resistant products. They are sometimes called 'forever chemicals'. Many people are concerned about PFAS in drinking water (Opens in new tab). However, research has shown the health effects of PFAS appear to be small. Health authorities are monitoring how much Australians are being exposed to PFAS.

Australian experts reviewed and updated the safety limits for PFAS in drinking water in June 2025.

Bacteria and parasites

These include:

• Giardia
• Cryptosporidium
• Escherichia coli (E. coli)

At times, health authorities might advise people 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.

There are also safety guidelines for private drinking water (Opens in new tab) sources such as rainwater tanks or bore water.

Drinking water quality and safety

You can check for information about the safety of drinking water in your local state or territory.

• New South Wales (Opens in new tab)
• Victoria (Opens in new tab)
• Queensland (Opens in new tab)
• South Australia (Opens in new tab)
• Western Australia (Opens in new tab)
• Northern Territory (Opens in new tab)
• Australian Capital Territory (Opens in new tab) (ACT)

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.

You can stay hydrated by:

• carrying a water bottle with you
• keeping chilled water in the fridge on hot days
• flavouring water with lemon, strawberries or mint if you find it hard to drink plain tap water
• having water on the table when you're eating

Your local tap water supply is usually just as safe as bottled water. Also, plastic bottles used for bottled water are not good for the environment.

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

Dehydration in babies (Opens in new tab) and children can be serious and needs immediate medical attention.

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.

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

People who don't drink enough water every day are more likely to have problems such as:

• urinary tract infections
• headaches
• kidney stones
• constipation
• confusion

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.

If you or someone you care for are showing any signs of dehydration, drink some water straight away. Seek medical advice if the person is not getting better.

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
• iced tea (but avoid iced tea with added sugar)

It's very difficult to drink too much water.

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

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 may not be able to get rid of extra water from the body as well as healthy people. 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.

Visit Eatforhealth (Opens in new tab) for the Australian guidelines for how much water (Opens in new tab) and nutrients you need.

Get some tips for helping older people keep their fluids up (Opens in new tab).

Learn what to do if a boil water alert is in place (Opens in new tab).

Read the National Health and Medical Research Council (Opens in new tab) (NHMRC) Australian Drinking Water Guidelines (Opens in new tab) and their questions and answers about PFAS (Opens in new tab).

Languages other than English

Visit Health Translations (Opens in new tab) for information about the importance of drinking water (Opens in new tab) in different languages.

You can also 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.