GEF

Unit 5  |  Toward Sustainable Water Systems 129 5.2  Green Building andWater Conservation Technology Because buildings are responsible for over 10 percent of total water use in the U.S., the intelligent design of homes, offices, and commercial buildings has tremendous potential for water conservation and sustainability. Green building is a move- ment to design comfortable buildings with low energy and water use and reduced materials demand. As green build- ing practices become more widespread, water sustainability is growing into an increasingly vital component of building design, construction, and maintenance. As a part of the green building movement, commercial and public buildings are increasingly incorporating efficient appli- ances such as waterless urinals and variable-flow toilets to reduce their overall blue water use. Green buildings also make use of native plants for landscaping, cutting down on green water use as these plants typically demand less water than conventional varieties. Another growing approach in green building is the reuse of greywater for toilets, landscaping, and other non-potable applications. Another important aspect of green building and water sustain- ability is the growing use of rainwater harvesting and storage systems. Rainwater harvesting, directly collecting rainwater for human use, has been practiced for thousands of years in India and other countries in order to recharge groundwater and provide water for irrigation. With increasing pressure on fresh- water supplies in many countries and regions, architects and builders are turning to this ancient practice in order to prevent storm water runoff and provide a more reliable water supply. A rainwater harvesting system typically collects water from build- ing rooftops and channels it through a filter to remove debris. Rainwater can be stored in barrels or cisterns and then pumped to supply non-potable water needs of a residence, school, or GREEN BUILDING Environmentally respon- sible and resource-efficient processes used in building, renovating, maintaining, oper- ating, and using a building interior and site space. Also, a sustainably built building. BLUE WATER Surface water found in lakes, rivers, or wetlands. GREEN WATER Water derived from precipi- tation that is held in the soil and nourishes plants. GREYWATER Wastewater that is created in homes or buildings that can be recycled onsite for irrigation, landscaping or construction. NON-POTABLE Water that is unsafe to drink. RAINWATER HARVESTING Accumulating and storing rainwater for human use.