As featured in a recent story on KCRW-89.9 FM’s “Which Way, LA?,” Professor Yoram Cohen and doctoral student Zita Yu, along with colleagues including Professor Michael Stenstrom, developed a low-cost technology that turns graywater waste into a residential resource. Named the Gray2Blue Mobile Wetland System, the technology has been at use in a home in West Los Angeles as part of a demonstration project supported by the Luskin Center. The system filters the home’s “graywater” – soapy water from sinks, showers and laundry – and pipes it out again to irrigate citrus trees and vegetable gardens. Plants are also a part of the system itself, helping to filter the graywater.

Roughly about 50 percent of the water that is used in a home ends up as greywater,” said UCLA engineering professor Yoram Cohen. “And if we can reuse that water, you can immediately see that the savings in water is going to be tremendous.” Cohen and Yu are now presenting their results to local and state water, health and zoning officials to inform decisions on how to regulate the further use of graywater in southern California.  The results include data from a financial assessment supported by J.R. DeShazo, an environmental economist and director of the Luskin Center.   All of this could mean that one day in the not so distant future, you too could turn the water going down your sink into a resource  your plants will love. Internationally, other cities are also starting to take notice. Yu, who was recently selected as a C200 Scholar by the prestigious Committee of 200 Foundation, presented on the regulation, technology and economics of onsite graywater reuse to the Water Supplies Department and its Advisory Board in Hong Kong. Hong Kong is considering including graywater into their water portfolio.