Thomas Hicks
Program Manager, LEED for Existing Buildings
U.S. Green Building Council®
Marc Heisterkamp
LEED Program Coordinator
U.S. Green Building Council®
Introduction
According to the U.S. Geological Survey, of the 26 billion gallons of water consumed daily in the United States, roughly 9.6 billion gallons, or 37 percent, are due to commercial consumption. Estimates of outdoor water use typically fall in the 30 percent range. With commercial water consumption on the rise further straining supplies, the cost of water is rising as well and, like energy prices, is outpacing inflation.
Fortunately, for facility managers, there are many opportunities to cost-effectively use water more efficiently. In the commercial building sector when it comes to saving water much attention is focused on the inside of buildings on water consuming equipment such as toilets, urinals, and faucets. And rightfully so since newer replacement systems offer great opportunities to save water and money. However, there are cost-effective water efficiency opportunities outside your building as well that go beyond installing the right toilet, urinal, or faucet. Water-efficient landscaping is one such strategy that can yield significant savings.
Water-Efficient Landscaping
While the footprint of buildings in urban settings is typically limited to the area of the building itself, facility managers in suburban locations are often faced with the challenge of not only maintaining their building but also maintaining large landscaped areas. At such buildings, the irrigation of landscaped areas typically consumes enormous amounts of potable water. Water-efficient landscaping however offers many economic and environmental benefits such as: lower water costs, lower landscaping labor and maintenance costs, lower energy costs due to lower pumping requirements, and reduced runoff. The key ingredients to minimal landscaping water use are the appropriate selection, placement and management of plants, and the selection of a highly efficient irrigation system—if a system is necessary at all.
Selecting the proper landscaping plants does not necessarily mean choosing those that have very low water requirements. Ideally, the water requirements of your plants should mirror the climate and natural rainfall in your geographic region. In general, this means choosing native plants. Selecting native plants and grouping water needy plants together can help minimize your irrigation needs. Tall plants and trees can be great additions, as they shade other plants and slow evaporation rates. Shade for your building, and associated reduced cooling needs can be an added benefit of using trees in your landscaping strategy.
Maintaining high quality soil and properly mulching are two very important tactics for maximizing the effectiveness of your irrigation system. Loose, high quality soil with an abundance of organic matter will allow your plants to become well established with deep root systems, thus necessitating minimal irrigation during dry weather periods. A top dressing of organic mulch can also help retain soil moisture and reduce competition from weeds.
After all these efforts, many facilities still find it necessary to have an irrigation system for use during dry summer months. High efficiency irrigation infrastructure utilizing drip systems, timers, moisture sensors or other technologies tend to be costlier to purchase and install but often have a reasonable payback period given the associated cost savings over time. Even with conventional systems, simple tactics such as regular leak maintenance and irrigating at night—when evaporation rates are much lower—can reduce wasted resources significantly. The ultimate goal is a well-planned landscaped area that eliminates the need for any irrigation system, leading to some considerable and immediate capital savings.
One example of water efficient landscaping can be found at the JohnsonDiversey Headquarters building in Sturtevant, Wisconsin which certified Gold in the U.S. Green Building Council’s LEED for Existing Buildings (LEED-EB) program. The JohnsonDiversey building has eliminated the need for potable water brought on site by capturing rainwater and runoff into a detention pond. The irrigation system is automated with a timer and controlled based on the moisture content of the ground soil. The system, which has been estimated to save two to four million gallons of water annually, cost approximately 6 cents per square foot to install and is achieving 2 cents per square per year in savings; resulting in just a 3-year payback.
Another example can be found at the Moss Landing Marine Laboratory (MLML), part of the California State University system, in Moss Landing, CA which achieved LEED-EB certification at the Gold level. During the first two years of operation at the 21-acre site, MLML used a drip system to establish root systems for their native perennial plantings toward their goal of creating a natural ecosystem. Aside from watering a very modest area for strawberries at the front entrance, MLML no longer has a need to irrigate on the site. Savings have been estimated in the thousands of dollars per year in water, labor, and equipment costs.
Closing
With water costs on the rise, getting your building more water-efficient is increasing in importance. There are many ways facility managers and property managers can cost effectively reduce water consumption. Old indoor water fixtures such as faucets, urinals, and toilets provide excellent opportunities. However, opportunities outside of the building that are often overlooked can also be highly cost effective. The focus of this article was on water-efficient landscaping, though there are still several other opportunities worth exploring such as rainwater reclamation, wastewater reuse, and high efficiency irrigation. As Spring gives way to Summer and the need for outside water use increases, you should ask yourself: Can I do more to cost-effectively reduce water consumption at my building? If yes, then check out the resources below to get started.
Resources
Your local government or water utility company should have information on local ideas and programs to help you use water more efficiently. Below are a few additional resources that are also useful.
The U.S. Environmental Protection Agency Water Use Efficiency Program gives background on the importance of water conservation measures and strategies for commercial, residential, and industrial facilities.
The American Water Works Association (AWWA) is an international nonprofit scientific and educational society dedicated to the improvement of drinking water quality and supply. It is the largest organization of water supply professionals in the world.
The U.S. Green Building Council offers credits toward achieving their Leadership in Energy and Environmental Design (LEED©) certification for reducing water use, utilizing innovative wastewater technologies, and water efficient landscaping.
