Inside a greenhouse at the Texas A&M AgriLife Research and Extension Service Center in Uvalde, Texas, Raul Cabrera inspects several groups of ornamental plants for signs of damage or distress. “This is the first component of our practical graywater investigation,” said Cabrera.

He, along with colleagues from the Uvalde center and the Texas Center for Applied Technology, started research to confirm the potential use of graywater for landscape irrigation. “Graywater,” Cabrera said, “is basically the soapy water that remains after tap water has been run through a washing machine or used in a bathtub, bathroom sink or shower and does not contain serious contaminants.”

The research is particularly relevant for drought-prone Texas, as it may reduce household landscape water use by as much as 10 to 25 percent or more, depending on the property size, geographical location and plant selection. Cabrera will continue this first phase of irrigation trials in the greenhouse for another two months as preparations are made for the second component of graywater experimentation.

“The second phase involves establishing an outdoor landscape here at the center,” he said. “For that, we are planting trees and shrubs along with flowering and bedding plants.” In this study, he will examine the medium- and long-term effects of graywater on these materials over a two-year period. “We are very interested in determining the effects of graywater use on physical, chemical and biological characteristics of the landscape soil.”

In addition, these landscape plants will be watered with a drip irrigation system, “to find out how well such an irrigation system performs and what kind of maintenance it might require when running graywater through it,” Cabrera added.