Express-News
Saturday, February 21, 2004
By Calvin Finch, Conservation Director, SAWS, and Horticulturist
GRAYWATER

            Graywater is the water from washing machines, showers, bathroom sinks, and bathtubs. Blackwater is the water from toilets and kitchen sinks. Based on a review of available research and the input of public health officials, medical doctors, engineers, environmentalists, irrigators, plumbers, and horticulturists that attended a Graywater Summit in December 2002 in San Antonio, graywater is a safe source of water to be used to irrigate lawns and landscapes. Arizona has rules concerning graywater that make it very easy for homeowners to use it to water their landscape. As a result, an estimated 10% of all landscape irrigation is done by graywater. In Texas the regulators have treated graywater and blackwater exactly the same.

            In 2003 the Texas legislature tried to change that situation by directing the Texas Commission on Environmental Quality (TCEQ) to rewrite the rules to make it easier for homeowners to use graywater, if they choose. Drawing from the information collected at the San Antonio Graywater Summit, Representative Robert Puente authored the legislation. His idea was that, since the research indicates that graywater can be used safely, there is no reason that Texas homeowners should not be allowed to use the resource on their own lawns. Graywater use will save homeowners money on their water bills and result in more potable water available for other uses. That is good news for cities like San Antonio where new water resources will be very expensive.

            In Arizona homeowners are allowed to use up to 400 gallons per day of graywater on their landscape without a permit or inspection. They must apply it by surface flood irrigation (run it out the end of a hose), surface drip irrigation, or subterranean drip irrigation; it cannot be sprayed in the air. Graywater must also be used in the yard from which it originates and it cannot run off that yard. The graywater cannot be applied to the point of ponding either.

            The average household produces about 100 gallons of usable graywater per day. It costs between $65 and $650 to make the plumbing additions on a new home and three times that much to retrofit an established house.

            Unfortunately, so far, in Texas, the rules on graywater use make us treat it like blackwater. There is no evidence that the resource merits such a treatment, but the rules have not been changed. To insure that the state rules make graywater easy to use and to promote more effective use of the resource, a Graywater Advisory Group has formed. Led by Brian Lillibridge of the San Antonio Water System, the committee is dominated by Bexar County and San Antonio officials but also includes representatives from the Austin and Houston area. For more information on graywater and the Graywater Summit contact the SAWS Conservation Department at (210) 704-7354.

            San Antonio has reduced per capita water use by one third in one generation. If we are careful about lawn watering, everyone obtains low-flow toilets, and we make use of graywater and other recycled water (rainwater harvesting, air conditioning condensate, and treated sewer water) there is no reason we cannot lower per capita water use by another 15 percent in the next 20 years. These savings will not prevent water cost increases, but it will keep the increases at the minimum necessary to repair our aging infrastructure (pipes and sewer lines). Because of conservation, less expensive new water sources and treatment plants will be needed. Please do not be too quick to criticize increases in water and sewer costs—increases are inevitable. The key to the situation in San Antonio is how our rates relate to other Texas cities. Rates are going to increase everywhere. A community with a strong conservation effort, including use of graywater, has the best chance to keep rate increases at a minimum. My prediction is that, because of San Antonio’s success in conservation, our rates will not increase as fast as other Texas cities. We will maintain our standing as a city where water is less expensive than most other Texas cities.