PITTSBURGH, PA — A spoonful of sugar may make the medicine go down, as the adage runs, but it can also leave a bad taste in your mouth when you consider that it takes almost 300 gallons of water to produce about a buck's worth of sugar. Not a bucket of sugar, a dollar's worth, less than two pounds.

That's what researchers found according to a recent study from Carnegie Mellon University about the direct and indirect uses of water.

Marc Gunther reported last year about the embedded water in a Starbucks latte (it's almost 53 gallons) and the work being done by the World Wildlife Fund to promote development of standards for water stewardship.

The new research by Chris T. Hendrickson, the Duquesne Light Professor of Civil and Environmental Engineering at Carnegie Mellon, and his colleagues provides the first industry-specific estimates of annual water use in almost 30 years.

The study by Hendrickson, the co-director of the Green Design Institute at Carnegie Mellon, with Michael Blackhurst and Jordi Vidal, estimates water withdrawals for 428 industry sectors.

The researchers found that indirect use, also called embodied and virtual water, accounts for the majority of water withdrawals, coming to about 60 percent. That supply chain, or indirect, use exceeds direct use in 96 percent of all the sectors, as the chart below shows.

"The study gives us a way to look at how we might use water more efficiently and allows us to hone in on the sectors that use the most water so we can start generating ideas and technologies for better management," said Hendrickson in the university's announcement about the publication of his work. The study was featured in Environmental Science & Technology in February.

Here's a look at other key findings of the research:

• 90 percent of the direct water withdrawals are for agriculture and power generation.
• 30 percent of indirect withdrawals are for the food and beverage industry.

• It takes 140 gallons of water to produce $1 worth of milk.
• It takes 200 gallons of water to make $1 worth of cat and dog food.

“Studies like this are helpful and important because we are hearing more and more calls for effective water management,” said Klaus Reichardt, founder and CEO of Waterless Co, Inc., a manufacturer of waterless urinals and other water-conserving products.

“Millions of gallons of water are wasted each year unnecessarily, which could have social consequences as well as impact our fragile ecosystems," Reichardt said in a statement today.


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