LEED Green Projects

Americans’ use of the limited public water supply continues to increase as development expands. Municipally provided potable water is delivered to users for domestic, commercial, industrial, and other purposes and is the primary source of water for most buildings, but high demand is straining limited supplies. The resulting wastewater then overwhelms treatment facilities, and the untreated overflow can contaminate rivers, lakes, and sources of potable water with bacteria, nitrogen, toxic metals, and other contaminants. Additional municipal supply and treatment facilities must then be built, at public cost.

LEED encourages and recognizes efficiency measures that significantly reduce the amount of potable water used by buildings while still meeting the needs of the systems and the occupants. These measures involve all the water usage associated with buildings; such as indoor water for restrooms, outdoor water for landscaping, and process water for industrial purposes and buildings systems.

Efficiency strategies, combined with monitoring that tracks water consumption and identifies problems, can dramatically improve water conservation compared with comparable conventional buildings. Many LEED-rated buildings reduce potable water use by more than 50%, with direct benefits for the bottom line and the environment.

Indoor water use reduction can be achieved by installing water-efficient fixtures, using nonpotable water for flush functions, and installing submeters to track and log water use trends. Low-flow fixtures use less water specified in the EPAct 1992 requirements. Projects can further reduce their potable water consumption by designing and installing plumbing systems that can use captured rainwater or greywater in flush fixtures.

Landscape Irrigation is a significant component of many commercial buildings’ water use and thus an opportunity to conserve water. A reduction in irrigation water use can be achieved by specifying water-wise landscaping and water efficient irrigation technology, using nonpotable water for irrigation, and installing submeters to track and log irrigation trends. Project teams should incorporate native and adapted species in the landscaping design, because these plants tend to thrive without irrigation, pesticides, or fertilizer.

Process water is used for industrial processes and building systems, such as cooling towers, boilers, and chillers. These systems provide heat, cool air and water for building operations. Process water also includes the water used for certain business operations (such as washing machines and dishwashers). Commercial building projects can reduce process water use by selecting efficient cooling towers, chillers, boilers, and other equipment, and by integrating harvested rainwater and nonpotable water to work in conjunction with the specified equipment.