Smart faucet could help save water

hands washing under a faucet in a sink
Stanford News

ARTICLE WRITTEN BY TAYLOR KUBOTA

"Barely hidden from his study participants, William Jou, a former graduate student in mechanical engineering at Stanford University, pulled off a ruse straight out of The Wizard of Oz. Except, instead of impersonating a great and powerful wizard, Jou pretended to be an autonomous sink. He did this to test whether a sink that adapts to personal washing styles could reduce water use.

A faucet with anything close to the brains of a mechanical engineering student doesn’t yet exist. So, Jou and his colleagues in the lab of Erin MacDonald, assistant professor of mechanical engineering, made the next best thing: a faucet that seemed to automatically adjust to a user’s preferences, but was actually controlled by Jou.

The results of their sly experiment, detailed in a paper presented Aug. 20 at the ASME 2019 International Design Engineering Technical Conferences & Computers and Information in Engineering Conference (IDETC/CIE), support the idea that thoughtfully designed smart sinks could help conserve water by regulating water use and nudging users to develop more water-conscious habits.

“We looked at the faucet because that’s where a lot of water usage in the home occurs, but when you compare your sink to other products in the house – a thermostat or refrigerator – you see that there haven’t been updates to how the sink works in a very long time,” said MacDonald, who is senior author of the paper. “There have been small updates but nothing that really harnesses the power of technology.”

Participants in this experiment had to wash dishes three times, with Jou secretly controlling the temperature and flow of the sink during the second washing only. With Jou involved, participants used about 26 percent less water compared to their first washing. In the third round, they still used 10 percent less water compared to the first round, even though the sink was back to being brainless. This shift in water use happened without participants knowing the experiment was about water conservation.
 
“Water conservation is particularly relevant given our location in California,” said Samantha Beaulieu, a graduate student and co-author of the paper. “We also wanted to see if people’s habits were adjustable; if interacting with this faucet could then change how people interact with a manual faucet. The results we found seem to indicate that’s possible.”