Virtual water is the water “hidden” in the products, services and processes people buy and use every day. Virtual water often goes unseen by the end-user of a product or service, but that water has been consumed throughout the value chain, which makes creation of that product or service possible.
What Does Virtual Water Mean?
Virtual water, also called “embedded water” or “indirect water,” is the water “hidden” in the products, services and processes people buy and use every day. Although virtual water goes unseen by the end-user of a product or service, that water has been consumed throughout the value chain, which makes creation of that product or service possible. (This meaning has become common although it differs from the technical and historical definitions, both of which are discussed below in the section called “Virtual Water and Virtual Water Trade.”)
For the purposes of Water Footprint Calculator, virtual water is used interchangeably with indirect water. Conceptually, both mean the water consumed at every step in a value chain of a given good, service or process.
By contrast, direct water use is the water that is seen, felt and used in a given time and location to produce an item or service (think “tap water”). Another way to envision direct water use is that it is the water necessary to carry out an operation or activity. In other words, at any given point in time in the creation of a product or service, it is the water used in the specific activity that comes directly from a pipe or spigot. For instance, a microchip manufacturer who uses highly distilled water in its process, or a beverage bottler that cleans bottles, are both directly using water in their operations. When taken together, all the steps in which direct water is used add up to the total water required to get a finished product to consumers. That total can be considered virtual water content.
Virtual Water and Direct Water: Examples and Differences
Water for Pasta
To make a bowl of pasta, water is required to boil the dry pasta in the pot – this is direct water use for the person eating that pasta at home. In order to produce the pasta, water is required at many steps along the value chain, and when the water used at those steps is added up, it makes up virtual water content for that pasta. Some of these steps include: water to grow the wheat; water to produce the fuel for machines to harvest the wheat and transport the pasta to the store; and water to create the electricity for processing the wheat into flour and pasta. (Learn more about Food’s Big Water Footprint.)
Water for Jackets
When a person wears a nylon jacket to the point where it gets dirty, water is required to clean it in a washing machine – this is direct water use for person who wore the jacket. In order to produce the jacket, water is required at many steps along the value chain, and when the water used at those steps is added together, it makes up virtual water content for that jacket. Some of these steps include: water to drill, produce and refine the oil and natural gas that makes nylon; water to make the electricity for manufacturing the jacket; and water to produce the fuel that moves vehicles and transports the jacket to the store. (Learn more about The Hidden Water in Everyday Products.)
Virtual Water and Virtual Water Trade
The virtual water concept was first conceived as a way to understand how water-stressed countries could provide their people with adequate supplies of food, clothing and other water-intensive items. However, because many goods and services are now exchanged through global trade, water-scarce countries rely more and more on the water resources of other countries to supply their consumer product needs. Accordingly, a country with limited water resources often imports water-intensive goods like cotton textiles rather than have local growers cultivate cotton crops at great cost to their local water conditions.
There are overlaps between virtual water and water footprints, but they are not equivalent. The Water Footprint Network summarizes the two concepts in this way:
“As food and other products are traded internationally, their water footprint follows them in the form of virtual water. This allows us to link the water footprint of production to the water footprint of consumption, wherever they occur. […] Virtual water flows help us see how the water resources in one country are used to support consumption in another country.”
While virtual water and water footprint can both refer to the water used to produce an item, the water footprint concept can be applied more broadly. For instance, the virtual water content of a product is the total sum of the water used along value chain. On the other hand, a product’s water footprint can be analyzed and separated into the components of water footprints – blue, green and grey. Further, that product’s water footprint can be assessed to determine whether the production process is sustainable within its local water and ecological conditions.
Virtual Water History
The virtual water concept was the brainchild of Dr. Tony Allan, a Middle Eastern specialist. Professor Allan came up with the concept during research on Middle Eastern and North African countries that he identified were able to meet their food needs in spite of struggling with water scarcity. By importing food from water-rich countries, these water-stressed countries were able to overcome water scarcity in their environment and economies. Professor Allan won the Stockholm World Water Prize in 2008 for developing this concept (among others).