[Editor's note: This article originally appeared at Ecosystem Marketplace and is reprinted with permission.]

Anyone who's ever squeezed a bag of oranges into a single glass of juice knows, at least intuitively, that a whole lot of water goes into that one little refreshing gulp. But would you believe it takes 518 liters of water for just one carton of juice?

That's the low-ball figure that the Coca-Cola Company and The Nature Conservancy (TNC) came up with after carrying out a water footprinting exercise on the company's orange juice supply chain.

The figure takes into account the water pulled from the ground and sky to grow the oranges, the water pulled from pipes to make the bottles, all the water used in transporting the product, and the clean water contaminated by the whole process. It also varies widely depending on where the oranges are grown -- one brand, which takes oranges from Florida and Brazil, uses 651 liters of water for just one carton of juice.

The same exercise revealed the company uses less than 70 liters of water to make one liter of its trademark dark beverage, at least when they're producing it in the Netherlands using Dutch sugar beets.

Environmental groups like TNC can use this information to monitor corporate impacts on the environment, and companies like Coca-Cola can utilize it to measure both their liability and total water needs. That's why the two teamed up, applying methods outlined in The Water Footprint Organization's Water Footprint Manual and its "footprint calculator" to two Coca-Cola products (orange juice and Coke) and one key ingredient (sugar from sugar beets).

They went public with the results of their footprinting exercise at World Water Week in Stockholm earlier this month and published them in "Product Water Footprint Assessments: Practical Application in Corporate Water Stewardship." (PDF)

The question now is how to best use these types of reports; it could develop into the basis for a water trade system. For now, companies are voluntarily utilizing it to establish more sustainable -- and economical -- water use practices.

Cutting Water on the Farms

When applied, these results can be used to monitor and respond to the areas of production that have the largest water footprint.

In the low-ball example above, for example, Coca-Cola found that the so-called "green" footprint from the farms they work with accounted for 319 of the 518 liters. The "blue" footprint (factories and processing) used up 115 liters, and the "grey" footprint (pollution) was just 84.

To decrease these, the company, with its partner farms, will focus its efforts on developing more sustainable agriculture practices, according to Denise Knight, Coke's Water and Sustainable Agricultural Director.

The Process of Water Footprinting

When the Water Footprint Network's manual is applied, corporations can develop better stewardship practices to reduce their water footprint, including the improvement of water use efficiency in the production cycle.

As in biodiversity markets and other offset-based schemes,  water footprinting isn't a cure-all for water-use issues. Instead, the Water Footprint Network says the process should be used to reduce water usage to a bare minimum and then generate offsets "by making a 'reasonable investment' in establishing or supporting projects that aim at a sustainable, equitable and efficient use of water in the catchment where the residual water footprint is located."

Coca-Cola said it plans to "safely return to communities and nature an amount of water equivalent to what is used in all of our beverages and their production."  In one area, the company established a partnership with WWF (formerly the World Wildlife Fund) to develop more sustainable practices in the specific areas of the agricultural supply chain. To date, the partnership has led 19 cane farmers to adopt practices that increase fresh water availability in the Great Barrier Reef region.