Americans use twice as much water as they think they do, according to a new study from researchers at Indiana University (IU). U.S. water consumers also have little idea of how much water is needed in the cultivation of foods they eat, and they don’t have a good grasp of the best ways to conserve water. Published in March in Proceedings of the National Academy of Science (PNAS), the study, “Perceptions of Water Use,” is based on an Internet survey of 1,020 people.
When asked for the most effective strategy they could undertake to conserve water in their lives, or what other Americans could do, most participants mentioned curtailment, such as taking shorter showers (43 percent) or turning off the water while brushing teeth (17 percent), rather than efficiency improvements, such installing low-flow or water-conserving toilets or using a higher-efficiency clothes washer, as recommended by EPA and other authorities. For a sample of 17 activities, participants underestimated water use by a factor of two on average, with large underestimates for high water-use activities.
Americans also tended to underestimate how much water was “embodied,” or used to cultivate, different food staples, according to the survey. When asked about the amount of water used to produce a pound of sugar, rice, cheese or coffee, the survey respondents said they were all about the same. These staples actually require widely different amounts of water: 157 gallons for a pound of sugar; 299 gallons for a pound of rice; 606 gallons for a pound of cheese; and 2,264 gallons for a pound of coffee.
The study’s lead author, Shahzeen Attari, an assistant professor in the IU Department of Public and Environmental Affairs, wrote: “Most Americans assume that water supply is both reliable and plentiful . . . Water is a really essential but neglected resource. We need to start paying more attention to water just in general.”
The PNAS abstract is online at www.pnas.org/content/early/2014/02/26/1316402111.