Tracking the U.S. Domestic Food Supply Chain's Freshwater Use over Time

The U.S. food system uses freshwater from both surface water and groundwater sources (both blue water) throughout the domestic food supply chain, from on-farm irrigation to water used in the home kitchen. In this report, we study water use in the U.S. food system in 1997, 2002, 2007, and 2012 using the most recent benchmark economic datasets and an environmental input-output model. Our results show that blue water use has increased and decreased over the 4 time periods, but surface water is consistently the primary source of food-related water use. The U.S. food system used 34 trillion gallons of blue water in 2012, or 30 percent of the blue water used throughout the U.S. economy. We find that the majority of water use was in the crop and livestock production stages, although supply chain stages downstream from agriculture (processing and packaging, distribution and marketing, energy, and households) used 32 percent of the U.S. food system’s blue water in 2012. This research also considers specific food categories. In 2012, the fresh vegetable category required the most blue water at 5.14 trillion gallons.