Woman Drinking Water

How much water should we drink?

We often hear recommendations about how much water we should drink. But there’s just one simple rule that all health authorities agree on; drink to satisfy your thirst – no more, no less.

As the weather heats up, we need to make sure we are adequately hydrated. But how much water exactly should we drink?  

As it turns out there's just one simple rule: drink to satisfy your thirst - no more, no less.

Adelaide-based urogynaecologist Dr Ian Tucker, who advises the Continence Foundation of Australia on a range of health issues, says there is absolutely no scientific evidence to suggest there are health benefits to drinking more water than that required to satisfy our thirst. In fact, excessive fluid intake can be dangerous if taken to extremes.

Dr Tucker describes it as a simple case of arithmetic; we need to take in enough fluid to make up for the amount we lose each day, which is normally around two litres (of which 1.5 litres is urine and the rest perspiration and water vapour lost through breathing).

We also need to consider that we take in about one litre of fluid daily through food, based on a normal diet (fruit, vegetables, cereal, soup etc.). This leaves about one litre of fluids to make up the difference, which is about six tea cups or small glasses.

“Obviously this intake will need to be varied on hot days and at times of significant exercise. But even then, the urine output should still be approximately 1.5 litres a day,” Dr Tucker said.

He said our urine colour, which should be pale lemon, is another good indicator as to adequate fluid intake. Any liquids - including tea and coffee - were suitable for hydration, he said, with alcohol the only exception.

“That’s because alcohol is a diuretic. There is this misconception that coffee is a diuretic too, which is incorrect. There is no diuretic effect from coffee.”

He also warned against excessive fizzy or caffeine-based drinks, which could trigger urge incontinence in some people with bladder dysfunction.

Dr Tucker’s recommendations are backed by Kidney Health Australia, which has a position statement on the issue.

For advice on continence, bladder or bowel issues, phone the National Continence Helpline (1800 33 00 66).

 Important exceptions: 

  1. Excessive urine output (polyuria), which leads to excessive thirst, may be an indication of diabetes. Seek medical advice if this is the case.

 2.  Older people may not get strong thirsty signals from the brain, putting them at risk of dehydration, and so should be reminded to drink. However, the urine output should remain about 1.5 litres a day.