LEED Water Conservation
Julius Ballanco, PE
The latest major effort in water conservation has been with LEED buildings. LEED stands for “Leadership in Energy and Environmental Design.” The program is relatively new, only about five years old, under the auspices of the U.S. Green Building Council. USGBC is a private organization, not associated with the government. Its interest is in promoting green building design.
Some plumbing manufacturers are promoting that you can obtain all your LEED points by using their products. You may be wondering what these LEED points are and why you need them.
First, you need to understand how LEED applies to a building. There are no government agencies or plumbing codes requiring buildings to be LEED-certified. LEED is strictly a voluntary program.
However, in certain states, there are tax incentives for green building design. One means of demonstrating that a building is a green design is by having a LEED certification.
There are four classification levels or ratings in the LEED program: certified, silver, gold and platinum. The different levels are based on points obtained in the design, construction and operation of a building. The certified level requires a minimum of 26 points; silver requires 33 points; gold is 39 points; and platinum requires 52 points.
Green building design is more than just water conservation. There are a number of categories in which points are assigned to a building. These categories include: sustainable sites, water efficiency, energy and atmosphere, material and resources, and environmental quality. The one category that impacts the plumbing profession directly is water efficiency. There are five points possible under water efficiency.
The five points available are for five different areas of water efficiency. Two of the categories deal with landscape efficiency. One of the hidden secrets in water conservation is that irrigation (simply watering the lawn) consumes a large quantity of potable water.
The building landscape design can reduce the amount of water required for irrigation. Or, the design of the building can include water re-use. The two most common methods of water re-use are gray water irrigation and storm water harvesting. Of course, a design can combine these two concepts by using gray water and storm water for irrigation.
Water re-use is still in its infancy in this country. The primary reason that water re-use has not gained in popularity is the high cost of installing the system. Storm water harvesting can be less expensive to install, however, the system may have to be supplemented when there is a drought or during dry months.
For gray water treatment, a secondary drainage system must be installed in a building. The gray water collection system would only receive the discharge of lavatories, sinks, bathtubs and showers.
The gray water still requires a minimal amount of treatment before it can be used for irrigation; you don't simply collect the water and spray it onto the lawn. There are still soaps, greases, bacteria and other waste items in the gray water.
The objective of LEED is to reduce the amount of potable water used for irrigation by 50 percent.
Fixture SavingsAs for straight water conservation of plumbing fixtures, points are awarded for reducing overall water use by 20 percent and 30 percent. If you hit the 30 percent reduction, you pick up two points in LEED certification. The problem with acquiring these points is that the baseline numbers already assume that the plumbing fixtures meet the water conservation requirements. Hence, the use of a 1.6-gallon per flush water closet will not garner any points.
Water conservation can be achieved by installing a water closet that flushes only 1.1 gallons. A dual-flush water closet would also conserve water by having a much lower water usage for a half flush vs. a full flush. Another consideration is the use of nonwater-supplied urinals. This would save 1 gpf with each use. For sinks and lavatories, a 1.5 gpm aerator can be installed instead of the standard 2.2 gpm aerator.
Additional water conservation can be demonstrated by the use of automatic faucets on lavatories. While they don't initially appear to save water, automatic faucets, in fact, save a tremendous amount of water by only operating when a person's hands are within the activation range of the faucet. When doing an analysis of the use of a lavatory, an automatic faucet saves well more than 30 percent of overall water use of the fixture.
The final category for obtaining plumbing points is in wastewater reduction. Of course, this category is directly tied to the previous categories. You can reduce the amount of wastewater treated by reducing the amount of water discharging to the public sewer system or by re-using the gray water.
The wastewater discharge must be reduced by 50 percent to receive the one point assigned to this category. The other option is to treat 100 percent of the wastewater on-site to a tertiary level. This means that at the end of the treatment process, the water can be safely discharged into a local stream or river.
The beauty of the LEED program is that it allows you to come up with any innovative means of conserving water and reducing the amount of wastewater discharge, you are not required to follow prescriptive measures. You simply have to figure out the best and most efficient way of saving water for the particular building in question.
You can get involved by proposing additional ways for conserving water. Work with the design community and the LEED professional by providing alternative solutions. Who better to be involved than the plumbing contractor?
There are those who thought the LEED program would be a flash in the pan. They predicted its early demise. They were wrong. LEED is gaining in popularity. The program has even been extended to existing buildings. Expect to see more and more buildings attempt to get LEED accreditation.
You can help by offering your expertise in ways of conserving water and reducing wastewater discharge.