How much is enough? You might be surprised!

A commonly held belief is that drinking large volumes of water is beneficial for health. This is often quoted by the health and fitness industry, however there is no medical or scientific basis. In fact, high volumes of water can be detrimental to health for some people. A large review published in 2018 found that there is no need for most people to be drinking 8 glasses of water per day. (Wood et al, 2018).


Limiting fluid intake can help with bladder control

Drinking too much fluid can exacerbate certain bladder conditions. If you suffer from bladder urgency (sudden need to rush to the toilet, with or without wet pants) and / or frequency (having to visit the toilet often), it may well be beneficial to reduce your fluid intake. There are studies showing that reducing total daily fluid intake to 1.3 litres per day can significantly improve urgency and frequency.

It is important however, not to overly restrict fluid. I often have patients tell me that they significantly limit their fluid, even to the point of not drinking anything at all some days if they are going out, so that they don’t leak. This can cause dehydration and can make the urine too concentrated, which actually irritates the bladder lining and causes you to want to go to the toilet more. As well, the bladder gets used to holding smaller and smaller amounts and the problem just gets worse!


How much is too much?

Drinking excessive amounts of fluid (4-5 litres per day) can be dangerous for your health. Long term consumption of such high volumes may cause kidney problems.


How much fluid is enough?

The body is unable to produce the water that it needs for survival. We therefore need to consume fluids on a daily basis. Most adults need to consume 1- 1.3 litres per day to replace fluid lost from the kidneys (urine), lungs (breathing), and the skin (sweating).  Remember too that you get fluid from the food you consume – around 20% of our daily fluid comes from food.

Note: If you are in a very hot environment or are sweating excessively (eg with exercise, heavy manual work etc), there is a need to drink more than this.



There are some specific conditions that require people to have a higher fluid intake (ie more than 1 – 1.3 litres per day).

This includes people who:

  • have a history of kidney stones
  • have previously suffered a stroke
  • suffer from migraine headaches

If you have a history of the above conditions you should be aiming for 2 litres of fluid per day.


What if I suffer from recurrent urinary tract infections?

There is also evidence supporting higher volumes of fluid for people with a history of urinary tract infections. Drinking 2.5 – 3 litres of fluid per day has been shown to help prevent recurrent bladder infections in women at risk of recurrence.


How do you know you are drinking enough if you reduce your fluid intake?

If you are wondering if you are getting enough fluid, a more reliable way of checking is to measure how much urine you are producing (rather than what you are drinking).  Measure how much you pee each time you go to the toilet, over a 24 hour period. If the total amount is around 1.3 litres then you are perfectly well hydrated.

Fluid consumption is actually a less reliable measure as it does not allow for greater than normal sweating in hot environments, or with exercise etc. In these circumstances higher fluid intake is required as more water is lost through the skin, but ideally the bladder output would still be around 1 – 1.3 litres per day if you are drinking the correct amount.  In other words, adjust what goes in to maintain what comes out at around 1 – 1.3 litres.

An easier way is to check the colour of your urine. It should be a pale straw colour mid-afternoon (unless you are on medication that changes it e.g. some vitamins).


If I am thirsty does that mean I am dehydrated?

No it does not. Most people experience a sense of thirst well before the body is dehydrated. As a general rule, if you feel thirsty, listen to your body and have a drink.


What sort of fluid is best?

Total fluid intake of 1 – 1.3 litres per day includes everything you drink, not just water. So tea, coffee, juice etc all count towards the total.

Caffeine: Caffeine is not a diuretic i.e it will not make your bladder fill more quickly.  However, some people are sensitive to caffeine when it does reach the bladder, and feel like they need to go to the toilet more often – if you are one of these people, you will know about it.

Note that caffeine is present in some energy drinks, some over the counter pain medications (e.g. Panadol extra) and some chocolate.

If you are wishing to reduce your caffeine intake, do it slowly or you will experience withdrawal (headache, nausea and feeling faint).

Alcohol: this is a diuretic, so your bladder will fill more quickly.

Carbonated drinks:  any carbonated drinks can cause bladder irritation (and urgency symptoms). This includes sparkling water. Try eliminating all fizzy drinks and see if it makes a difference.

Artificial sweeteners: these can cause bladder irritation in some people – leading to urgency and frequency.


What about preventing constipation?

If you drink less than 500ml total fluid per day, then this will likely be causing constipation. Otherwise, even if your fluid intake is low, the body is good at limiting urine production and keeping the fluid in the gut.

People often tell me that they drink several litres a day to help with their bowel function. However, all that is happening is that you will be producing more urine and having more frequent visits to the toilet! It won’t be helping with the constipation. Stick to the recommended 1 – 1.3 litres.


Does it matter how fast I drink?

Many people can quickly drink a glass of water with no problems. Some however can benefit by drinking more slowly. As the bladder fills, the walls stretch and for some, faster filling causes more stretch than the bladder can handle, and this causes urgency. If you suffer from bladder urgency or frequency, try slowing down the rate at which you drink and see if it helps.


What else can I do to help with overactive bladder symptoms? (urgency +/- leakage, frequency, getting up several times at night).

Making the changes outlined above can help reduce bladder symptoms. If you are still having problems you can get further help from an experienced pelvic floor physiotherapist. They will be able to help you with pelvic floor muscle training, urge control strategies, bladder training and deferment techniques.


Click here : for more information on types of urinary incontinence, and how to do pelvic floor exercises.



Wood LN. Markowitz MA, Parameshwar PS, Hennemann AJ, Pqawa SL, Anger JT, Eiber KS (2018) Is it safe to Reduce Water Intake in the Overactive Bladder Population? A systematic review. The Journal of Urology, 200 (2), pp 375-381