Virtual Water, Real Impacts: World Water Day 2012

By Christina Catanese

In this digital age, it seems everything is becoming virtual.  There are virtual pets, virtual reality, virtual keyboards, and virtual books.  From your computer, you can shop virtually, and take virtual tours.

But virtual water?  How does that work?  We can’t consume water that we can’t see… or can we?

Virtual water is a concept that refers to the water needed to make a product.  We know we should drink 8 glasses of water a day to be hydrated, but it’s easy to overlook the gallons and gallons of water required to produce the food we eat and the things we buy.  This water is virtual in that the end-consumer of a product is not directly using water, but there was water that went into producing the item.  So by consuming these items, we use water indirectly, hence virtually. You might be surprised at how much the hidden water that we consume adds up.

Let’s take the cheeseburger I had for lunch yesterday, for example.  Estimates are that a 1/3 pound burger requires 660 gallons of water to be produced, most of which is for the beef.  One pound of beef requires 1,799 gallons, a pound of cheese requires 700 gallons, and two slices of bread require 22 gallons.  Why does meat require so much more water?  Well, it factors in what’s needed during the entire life of a cow: water for the animal to drink, to grow feed and hay, and to keep stables and farmyards clean.  Guess I should have gone with the salad after all: lettuce only takes about 13 gallons per pound to produce.

Once I started looking for this hidden water, the amount of water I found that I eat got higher quickly, and I started to see connections.  How much water did it take to grow the coffee I drank this morning, and to produce the milk and sugar I put in it?  The banana I put in my cereal?  The cereal itself?  The candy bar I had for a mid-afternoon boost?

Beyond diet, what about the paper all over my desk (1,321 gallons to make 500 sheets)?  The jeans I’m wearing (2,900 gallons for one pair)?  How about the water it takes to produce the fuel that brought all these things to Philadelphia for me to use and consume?  And the energy to power all my appliances at home?  The hidden water we use really adds up, and when you do the math, it starts to seem much more real than virtual.

The estimates of virtual water in this post come from National Geographic and the Water Footprint Network.  Check out this Water Footprint Calculator to see how much water you’re using, virtual or otherwise!  Are you surprised by these numbers?  Do they make you want to change your consumption habits?  WaterSense labeled appliances are one way to reduce your water footprint; what others can you think of?


March 22 is World Water Day, a commemorative day by the United Nations to raise awareness about water issues.  This year’s WWD focuses on water and food security and production all over the world.

About the Author: Christina Catanese has worked at EPA since 2010, and her work focuses on data analysis and management, GIS mapping and tools, communications, and other tasks that support the work of Regional water programs. Originally from Pittsburgh, Christina has lived in Philadelphia since attending the University of Pennsylvania, where she earned a B.A. in Environmental Studies and Political Science and an M.S. in Applied Geosciences with a Hydrogeology concentration. Trained in dance (ballet, modern, and other styles) from a young age, Christina continues to perform, choreograph and teach in the Philadelphia area.


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