About 50% of the water used inside U.S. homes can be reused to irrigate landscapes and flush toilets, according to a gray water report released by the Pacific Institute last week. The Overview of Greywater Reuse examined the application of gray water systems worldwide to determine how the wastewater generated from sinks, baths, showers and clothes washers could be reused to reduce demand for more costly, high-quality drinking water.
“In California, there are a lot of reasons why we’re looking for new and innovative water sources, including the legal restrictions that are coming to bear on our ability to move water around the state,” said Juliet Christian-Smith, senior research associate at the Oakland-based research institute. “Climactic changes are occurring…. We are looking at a future with less of a natural reservoir in our snow in the Sierras and less water available from the Colorado River system.”
In 2009, California modified its plumbing code to allow the reuse of certain types of gray water. The Pacific Institute was interested in examining how that change might affect the state and aid its development of a “soft path of water management.”
“The 20th century was dominated by a paradigm of water supply and water extraction which focused on large-scale centralized resources like reservoirs, canals and pipelines that have been very successful at moving water and providing a higher standard of living but also come with social, environmental, energy and economic costs that weren’t apparent from the beginning,” said Christian-Smith. “As we move into the 21st century, we’re starting to think about other options … such as demand management — conservation and efficiency — and to look at new technologies that reuse water.”
Australia is the most progressive country in terms of gray water policy. The government for this drought-prone continent not only promotes gray water reuse but provides monetary incentives for systems that recycle wastewater from showers and sinks to flush toilets and irrigate outdoor plants. Korea, Cyprus, Japan and Germany are also at the forefront of gray water technology implementation.
While there is no national policy in the U.S. regarding gray water, about 30 of the 50 states have some sort of gray water regulation, some of which require treatment of the wastewater before its reuse. Other states, including Arizona and California, use a landscape’s soil as a natural filter to reduce potential contaminants.
According to the report, which cited a study conducted in Barcelona, Spain, this year, factors determining public acceptance of gray water include a perceived health risk, perceived cost, operation regime and environmental awareness.
The Overview of Greywater Reuse is a starting point, Christian-Smith said, to “a larger project that will start to outline supportive and protective instruments” for understanding the long-term impacts of gray water reuse.
Source: Los Angeles Times
Photo credit: Don Kelsen / Los Angeles Times
Additional reading on greywater systems in Canada – http://www.cmhc-schl.gc.ca/publications/en/rh-pr/tech/03-100-e.htm