Toilet-to-tap: Gross to think about, but how does it taste?
Riverside, CA. – Here’s a blind test taste like Pepsi never imagined.
Researchers at the University of California, Riverside, recently published a study of recycled wastewater that did not focus on its safety-which has long been established-but rather its taste.
After years of drought, the notion of drinking recycled wastewater has gained momentum in California. Thoughts turned to all the water being discarded—to supplementing “conventional” groundwater with recycled water. But consumers were quick to flag the euphemism of “recycled.” Some have even branded the technology “toilet to tap.”
The water’s safety has been the source of most related research. The wastewater is treated using reverse osmosis. A preferred technology is called indirect potable reuse, or IDR. IDR reintroduces treated wastewater into groundwater supplies, where it re-enters the drinking water system. Six California water agencies already employ IDR. These include the Water Replenishment District of Southern California, the Orange County Water District, the Los Angeles County Department of Public Works, the Inland Empire Utilities District, the city of Los Angeles, and the city of Oxnard).
Studies have found IDR removes virtually all contaminants. But no one has considered its relative taste – at least, not in a blind taste test, and not in a scientific study.
The UCR study included 143 people, who were asked to compare IDR-treated tap water with conventional tap water and commercially bottled water.
“The groundwater-based water was not as well liked as IDR or bottled water,” said Mary Gauvain, a professor of psychology at UC Riverside and co-author of the study. “We think that happened because IDR and bottled water go through remarkably similar treatment processes, so they have low levels of the types of tastes people tend to dislike.”
Another surprise: Women preferred bottled water two-to-one over men.
The researchers’ best guess: Women register higher “disgust reactions” than men, which means their reactions to tastes they dislike are more extreme. These disgust reactions are the subject of the team’s next research paper.
About UC Riverside
The University of California, Riverside (www.ucr.edu) is a doctoral research university, a living laboratory for groundbreaking exploration of issues critical to Inland Southern California, the state and communities around the world. Reflecting California’s diverse culture, UCR’s enrollment is now nearly 23,000 students. The campus opened a medical school in 2013 and has reached the heart of the Coachella Valley by way of the UCR Palm Desert Center. The campus has an annual statewide economic impact of more than $1 billion. To learn more, call (951) UCR-NEWS.