People use lots of water for drinking, cooking and washing but even more for producing things such as food, paper and cloth.
A water footprint is an indicator that looks at both the direct and indirect water use of an individual, business, community, city or country.
Direct water use refers to the water we see coming out of the tap: the fresh water we use each day for drinking, cooking, showering, washing dishes and clothes, and gardening etc.
Indirect water use refers to the water that is used to manufacture the goods that we consume or produce, and the services that we use, as well as all of the water that is made unusable by pollution or wasted by non-use. That includes all of the water used to grow the food that we eat eat, to produce the things we use in daily life - clothes, books and furniture - and the water needed to produce the energy we use.
While this indirect water is "invisible", we often use far more of it than we realise.
In Europe, for example, the average person directly consumes between 100-150 litres of water a day - as drinking water, for washing clothes, bathing and watering plants.
But each person also indirectly consumes anywhere between 1,500 and 10,000 litres of per day, depending on where they live and their consumption habits.
Measuring water footprints can give us a clear picture of how water is used in today's society, and help us come up with strategies for more sustainable water usage.