Enter LEED®

One of the major forces raising awareness of sustainability and environmentally responsible design is the LEED® Green Building Rating System. LEED has become the most influential driver for green buildings, and includes a section that rewards water conservation efforts. The overall LEED system helps project teams determine environmental goals, identify green design strategies, measure and monitor progress, and document successes.

A product of the United States Green Building Council, LEED for New Construction (LEED-NC) provides a menu of green building measures in six major categories:

• Sustainable Sites, which includes credits for controlling erosion as well as considerations to reduce overall site disturbance.
• Energy and Atmosphere, which includes credits for optimizing energy performance and incorporates credits for use of renewable technologies.
• Materials and Resources, which offers credits for a range of sustainable designing strategies including the use of recycled building materials.
• Indoor Environmental Quality, which includes ways to establish minimum indoor air quality performance and occupant comfort and health.
• Water Efficiency, which includes ways to maximize water efficiency both in outside irrigation as well as indoor water usage.
• Innovation and Design Process, which addresses design measures not covered in the other five categories.

For the Water Efficiency category, the U.S. Green Building Council offers up to five LEED-NC credits: two for reducing potable water use for irrigation; one for reducing potable water use for sewage conveyance; and two for reducing potable water use inside a building. The last two credits, which comprise LEED-NC Water Efficiency Credit 3, are dedicated to reducing potable water use within the building.

Using LEED for Water Conservation

The architect must consider methods to reduce potable water use that go beyond the Energy Policy Act of 1992 (EPAct). Such methods include reusing roof runoff for non-potable applications, installing sensors and flow restrictors on water fixtures, installing dry fixtures, and other innovative methods. Such methods have a profound effect on the environment, and include:

• Environment. Water reduction benefits the total amount withdrawn from rivers, streams and other water bodies. In addition, such reductions reduce energy use and chemical inputs at municipal water treatment facilities. Conserving water can also minimize the frequency of outflow events (in a combined sewage system, raw sewage is discharged when the system breeches capacity).
• Economic. Water reductions minimize building operating costs, and lead to a more stable tax and water rate, as well as delaying water treatment facility expansions.
• Community. Water reductions save water for future generations. In addition, water reduction allows the community to grow without overburdening its water system.