How Much Is That Droplet in the Window?

Sept. 1, 2009

By Elizabeth Cutright

In 1998, UNESCO released a report entitled “The Real Cost of Water“, which states, “It costs money to make good quality water available from taps, and then return it to the environment after being treated.” Of course, anyone who’s ever received a water bill or plunked a quarter into a water dispenser knows that as a society we have placed a monetary value on water. But what about water that doesn’t come out of the tap? After all, there are imbedded water costs in just about every human activity. The UNESCO report points out, for example, that in addition to the 70% of fresh water used by agriculture (mostly through irrigation), industrial and energy sectors consume 22%, while cooking and human hygiene take care of the final 8%.

But that’s not the whole story. As we’ve discussed before, virtual water involves the imbedded water-related costs behind any product (including food and commercial goods). Therefore, that salad mix you just picked up in the store or that household detergent you bought last week, both have a virtual water price tag. Wouldn’t it be better if we were aware of all the attendant costs associated with a particular product or action? Imagine a world where products or services came with a label that included information detailing the amount of resources (both water and energy) required for their creation.

One example is the “Real Costs“ Firefox Plug-in. By using this application, users can calculate the amount of carbon dioxide (CO2) emissions generated by various forms of travel (i.e., plane versus car), with the idea being that travelers can make informed choices—based on their commitment to reducing their carbon footprint—when making travel arrangements. An added plus is that the Real Costs application tacks on an additional—non-monetary—expense to basic travel, thereby, illustrating the real impact (in terms of environmental impact and CO2 emissions) of jumping on that plane to Houston, TX.

Water Footprints Around the World

  • The average water footprint around the world is 1,243 cubic meters per year
  • US averages 2,500 cubic meters. (Equivalent to 2.5 million liters per citizen)
  • Russia averages 1,800–2,100 cubic meters
  • India averages approximately 1000 cubic meters
  • Australia averages 1,300–1,500 cubic meters
  • Mexico averages 1,300–1,500 cubic meters
  • Sub-Saharan Africa averages between 800–1,000 cubic meters
  • China averages 700 cubic meters

*Data provided by

But what about the real cost of turning on your sprinkler system? Or taking that extra long shower? Would we make different decisions if we were aware of the toll our everyday purchases and activities take on our water supply? On the Web, there are any number of resources available if you’re interested in the water footprint of different products. For example, at, you’ll discover that it takes 1,000 liters of water to produce one liter of milk, and an amazing 3,000 liters of water for one liter of rice. Even water has an imbedded cost. Did you know that in addition to the 17 million barrels of oil used in the overall production of bottled water, it takes 3 gallons of potable water for each gallon of its bottled counterpart?

But how does determining the hidden water costs behind basic human activities relate to water efficiency and conservation? First, the ability to quantify the amount of water used by society for all of its basic functions is vital to an effective water resource management plan. Why? Because without knowing the true water costs of your actions, you could implement a program or greenlight a project intended to conserve water that, in actuality, wastes more than it saves.

Additionally, in order to be able to make informed choices between Plan A and Plan B—like choosing between bill inserts and Web banners for your new public outreach program—you need to know the overall impact your choice will have on the resource you are trying to protect. After all, it can take as much 10 liters of water to produce one sheet of paper, but even going online requires some expenditure of energy (according to the World Resources Institute, about one gallon of water is consumed for each kilowatt-hour of energy:), so those e-mails have their own water footprint to contend with.

Finally, efficiency depends upon the ratio of work expended to benefit received. Many times, there are a variety of methods available to achieve a particular end, and knowing which of those many options is less water-intensive can make a big difference. As I’ve stated before, I believe that by redefining how we measure the value of water—by monitoring our “water footprint” and keeping track of our virtual water costs—we can harness new tools to help us protect, and efficiently manage, our resources.

Elizabeth Cutright is a past editor of Water Efficiency magazine.

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