Water Footprints

The concept of a water footprint was introduced by researchers trying to quantify the per capita volume used for direct (e.g., drinking, cooking, bathing) and indirect (e.g., products, services) purposes. Consumptive use is the most obvious component of the water footprint, but water is also lost to pollution, evaporation, and relocation to places where it cannot be reused. Perhaps not surprisingly, the water inherent in producing food and energy comprises a major portion of a person’s water footprint. Americans have the highest water consumption, with an annual per capita use (about 2600 cubic meters) that is more than double the global average. Because of their population density, cities require an area as much as 600 times that of their geographic boundaries to provide sufficient water. In addition, the electricity required to pump (relocate) water from productive watersheds to cities comprises a major portion of their energy footprint.