It takes about 10 liters of water to produce a bottle of beer, while about 65 cu. meters of water is needed to manufacture an automobile.
These figures are estimates worked out by Taikan Oki, a professor at the Institute of Industrial Science at the University of Tokyo, graduate student Tsuyoshi Kondo and other researchers.
In untypical research designed to explain in layman’s terms, they calculated the total quantity of water required for the process of brewing beer, starting with when barley is watered and including the water used during the manufacture of machines in a brewery.
They say Japanese indirectly use about 118 liters of water per day through the purchase of books, clothing and food.
The amount of water consumption expressed in this form is called a “water footprint,” or WF. The International Organization for Standardization has begun to work on the establishment of international standards for WF calculations.
Growing numbers of companies have also expressed interest in the water footprint. Oki said it is important for firms in grasping the effect of their activities on the environment and mapping out a strategy for saving water resources.
Computing estimates of the volume of water needed to manufacture each part, Oki and his group looked at cell phones and bicycles. They also examined how much water is needed for bread and soft drinks, including the containers they come in.
They learned that the water footprint for a mobile phone is about 912 liters, followed by 623 liters for a knit coat, 15 liters for a loaf of bread and 10 liters for a 623-milliliter bottle of beer. The water quantity for a personal computer is about 4 cu. meters.
The volume of water used in the final stage of production amounted to about 10 percent of the total water footprint for a car and about 14 percent for a personal computer, according to their research.
The group found out that the impact on water resources can be underestimated if water required for the output of resources and parts is not taken into account.
Similar research is under way in other countries, with some corporations in Europe and the United States closely studying water footprints of their products and taking steps to display them on the manufactured items.
In Japan, outdoor clothing maker Patagonia Inc. has started showing its products’ water footprints on its Web site, while Nestle Japan Ltd. has decided to carry out a study on the amount of water used in the entire process of making its products and announce it in such a way as the volume of water used for a cup of coffee.