There is so much advice and recommendations when it comes to how much water do we need to drink a day.

So how much is the right amount?

You have probably heard that eight glasses a day is what you should have. This advice appears to have come from a recommendation of the Food and Nutrition Board of the United States National Research Council from 1945 which has stated a suitable allowance for adults is 2.5 litres a day.

But there's no hard and fast rule on how much water you need to drink Pennie Taylor from the CSIRO said.

There are so many factors to consider such as our sex, bodyweight and how active we are. Another thing to consider is where you live, those who live in warmer climates and more humid climates tend to sweat more and lose more body fluids.

Australia's current dietary guidelines don't recommend a specific amount, but do recommend we drink plenty of water. There are Nutrient Reference Values that advise that adult men should drink about 2.6 litres a day and adult women should drink about 2.1 litres a day based on the average weight of men and women.

A good rule of thumb is 35 millilitres of fluid per kilogram of bodyweight. These fluids can come from any fluids such as tea, coffee, juices and even alcohol.