Environmental Protection

Gray Water May Help Texas Landscapes Stay Green

Researchers at Texas A&M University are investigating gray water, hoping that the reuse of ‘soapy’ water can become a statewide interest.

With water resources throughout Texas becoming scarcer, a Texas A&M AgriLife Research ornamental horticulturist is working with others to determine the feasibility of using gray water to irrigate home landscapes. Gray water differs from reclaimed water in that it is not captured water from sewer drainage or storm-water systems and then run through a waste-water treatment facility.

“There has been interest in and discussion about the possible use of gray water for irrigating home landscapes, but so far little formal research has been done to validate its practicality,” said Dr. Raul Cabrera, Texas A&M AgriLife Extension and Research Center in Uvalde.

Gray water is essentially “soapy” water left 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. Cabrera added that while it is difficult to precisely estimate the statewide potential for water savings through the use of gray water and application of the technology needed, it may reduce household landscape water use by up to 50 percent – depending on the size, type of landscape plants used, and geographical location.

“The average household uses as much as 50-60 percent of its water consumption for the landscape – grass, ornamental plants, trees, etc.,” said Cabrera. “Considering that the average family of four produces about 90 gallons of gray water per day, if this was used to irrigate a landscape, it could represent a significant water savings.”

“Implementing the use of gray water for landscape irrigation across the state could mean a tremendous water savings in terms of acre-feet of water, contributing to the water use and conservation goals of the recently released 2012 Water Plan,” he stated.

Using gray water is one of the easiest ways to reduce the need for potable water typically used in a home landscape, said Dr. Calvin Finch, director of the Water Conservation and Technology Center in San Antonio, which is administered by the Texas Water Resources Institute, part of the Texas A&M University System. The institute is participating in the gray water research, as well as providing funding.

Finch said the Texas 2012 Water Plan identifies more than 500 specific activities that, if implemented, would help meet the state’s future water needs. Some southwestern U.S. states, including parts of Texas, already allow for the use of gray water under certain restrictions, such as irrigation through delivery by flooding, subsurface or drip irrigation.

He added if essential aspects of the initial research are positive, additional involvement might include microbiologists and health officials to address any perceived health issues or concerns. Initial gray water testing and evaluation will take from nine months to a year, he noted.

“We hope the results will support the launching and development of a statewide initiative to conserve water resources that will involve many additional partners,” Cabrera added.

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