Embedded Water

Embedded water is also known as virtual water, and it describes the concept of the hidden flow of water that exists within the production and transportation of food, goods, and services. Water is hidden in beer, burgers, clothing, cars, homes, and even electricity. Water is used to produce all of these things, and it is present inside of these things, but we do not usually take this water into account when we think about the resources it takes to produce the things we use and eat on a daily basis. Embedded water is water used to produce food and non-food products. For example, it takes about 1100 drops of water to produce one drop of coffee. It takes 136 drops of water to produce one drop of tea. 

Most of the water we consume is in our food, about 65% of it. We eat 3496 meters of water everyday.  A tomato has 13 litre of water embedded; an apple as about 70 litres; a pint of beer about 170 litres; a glass of milk 200 litres; and a hamburger about 2400 litres. Much of this water comes from the large scale systems that are used to produce and process this food, especially when discussing animal products such as dairy and meat. Cooling and processing systems require large amounts of water. Large scale agriculture also uses and wastes a large amount of water in the growing of produce and the feeding of animals. For example, 200 kilos of beef takes on average 3 years to 'grow.' During this three years, the animal will consume nearly 1300 kg of grains and 7200 kg of roughages, the production of which requires over 3 million liters of water. The cow will also drink 24,000 liters of water per year. There will also be 7000 liters used to service the farmhouse and slaughtering processes. This all means that to produce 1 kg of beef, we need 15,400 liters of water.  

Our domestic consumption is about 137 litres per day, and it includes things such as bathing, cleaning, flushing the toilet, laundry, and cooking. This is the visible water use. There are two invisible pieces. The first invisible part is the water used for the production of industrial products such as paper, cotton, and clothes. This equals about 167 liters per day. The other invisible part of our consumption is associated with the production of our food, and that equals about 3496 litres per day. This means that 92% of the water we use is invisible to us on a daily basis. 

Most of the embedded water that we consume as a nation, about 70%, is imported from other nations in the form of imported goods and services. This importation of water is also referred to as virtual water trade. The term virtual water was coined by Professor Tony Allan, and the concept has helped us understand how much water is needed to produce the food and goods we need. When a country imports one tonne of wheat instead of producing it domestically, it is saving about 1,300 cubic meters of indegineous water. This 'saves' the country's water and allows it to be used elsewhere. The exporting country has exported 1,300 cubic meters of virtual water since the real water used to grow the wheat will no longer be available for other purposes domestically. 

For more information on embedded water and the virtual water trade and what you can do to help, click here

Also, here.