The Path to Plumbing Efficiency

Oct. 1, 2007
To some engineers, the Leadership in Energy and Environmental Design (LEED) Green Building Rating System seems complicated. However, LEED certification

To some engineers, the Leadership in Energy and Environmental Design (LEED) Green Building Rating System seems complicated. However, LEED certification deserves attention because — from an efficiency point of view — it holds the keys to sustainability in overall building performance. Although it may take extra effort to qualify for LEED certification, it is the best path for protecting long-term building performance. LEED benchmarks drive water-efficiency decisions in building designs, helping to protect one of our most precious resources.


In terms of plumbing water efficiency, facilities can qualify for two LEED credits: Water Efficiency (WE) credits 3.1, Water Use Reduction: 20 Percent Reduction, and 3.2, Water Use Reduction: 30 Percent Reduction.

WE Credit 3.1 requires that a facility reduce its water consumption by 20 percent. The use of plumbing products rated below the baseline fixture-performance requirements of the Energy Policy Act (EPAct) of 1992 contributes to this credit, as long as the building as a whole reduces water consumption by 20 percent below the baseline. For example, a building using a combination of faucets with 0.5-gpm aerators, water-closet flushometers utilizing 1.6 gal. of water or less, 0.5-gpf urinal flushometers, and no-water urinals, as well as other water-efficient plumbing fixtures, could reduce water consumption enough to be eligible for this credit.

To qualify for WE Credit 3.2, a facility as a whole has to reduce its water consumption to 30 percent below the baseline. As stated previously, plumbing fixtures can be rated below the baseline performance requirements. The only difference with this credit is the amount by which a facility's water consumption must be reduced.

Installing water-efficient plumbing fixtures that meet these standards could contribute up to two points toward LEED certification.


Current federal standards for flushing set the maximum water consumption for water closets at 1.6 gpf. Commercial, industrial, and institutional facilities, however, can gain greater efficiencies in flushing consumption without sacrificing performance. Facilities managers can save more water without worrying that their toilets will not flush appropriately, which can lead to double flushing. Double flushing to clear the bowl, as well as user discontent, can negate the benefits of installing lower-consumption fixtures.

Manufacturers, however, are putting more emphasis on developing high-performing flushing technologies that use even less water. Flushing systems available to specifying engineers include high-efficiency toilets (HETs) and high-efficiency urinals (HEUs).

A HET is defined as a fixture that flushes 20 percent below the current maximum-allowable flush volume of 1.6 gpf, which equates to a flush of 1.28 gpf or less. HEUs are fixtures that have an average flush volume lower than the mandated maximum 1.0-gpf flush volume. This category includes 0.5-gpf urinals and other fractional-flush models, as well as no-water urinals offering 100-percent water savings.

Water-efficiency measures in commercial buildings can reduce water usage by 30 percent or more. In a typical 100,000-sq-ft office building, sensor-operated, low-flow fixtures can save a minimum of 1 million gal. of water per year, based on 650 building occupants each using an average of 20 gal. per day.

Using showerheads with a 2.0-gpm water flow instead of the 2.5-gpm EPAct standard also can go a long way toward saving water without a user noticing any difference in performance. The same is true of lavatory faucets fitted with 0.5-gpm aerators: These faucets still can wash hands efficiently and hygienically while using less than the mandated maximum flow of 2.5 gpm.


For facilities managers with an eye on improving their plumbing systems, LEED is the guide for becoming more water and/or energy efficient even though certification may not be the project objective. For example, achieving LEED certification was not the initial goal for Donald Bren Hall, home of the School of Environmental Science & Management at the University of California, Santa Barbara (UCSB), even though environmental issues were a priority for the building project team. Upon learning of LEED, the project team discovered that many planned building features were eligible for LEED credits, and the team was able to secure the modest additional funding needed to purchase remaining building features to earn LEED certification.

Bren Hall earned LEED Platinum status in 2002 and has been recognized as the greenest laboratory facility in the United States. Since then, there has been a campuswide push for all buildings to attain higher standards for sustainability. The university plans to seek LEED for Existing Buildings certification for 25 other buildings, some of which already have been certified. At the very least, UCSB is using LEED as the benchmark for its sustainability projects to reap other monetary and environmental benefits that come with compliance.

Bren Hall's water-efficiency measures, such as connecting first-floor toilets to the municipal gray-water system, have been replicated in various ways and with different technology combinations elsewhere on campus. In other campus buildings, UCSB has installed numerous low-flow electronic faucets, low-consumption automatic and manual flush valves, and no-water urinals, which save about 300,000 gal. of water each year in one building alone.

The university recently installed its first commercial-grade, dual-flush flush valves, which give users the option of pushing down the manual flush valve handle for a full flush or pulling it up for a reduced flush. Although it is too early for the university to tell how much water the dual-flush valves are saving, the student body and faculty are supportive of technologies.


Although even five to 10 years ago, purchasing environmentally sound building components that met LEED compliance standards could have added more than 10 percent to total building cost, engineers and other specifiers now are finding that they can adopt higher sustainability standards without necessarily spending extra. As with any purchase, however, staying within budget is a matter of performing research up front to determine the additional value and payoff of specifying different systems and technologies.

For many plumbing systems, engineers are finding that low-consumption and low-flow fixtures initially cost little more — if they cost more at all — than higher-consumption fixtures. The real value proposition is when specifiers factor in long-term operating costs, including water and wastewater utility bills, plus the energy it takes to, for example, heat water for faucets and showerheads.

Building Bren Hall in a sustainable manner added 2 percent to the overall costs. However, planners considered the money well spent because energy savings quickly would recoup the investment. Consider the 300,000 gal. of water that the building's no-water urinals are saving: Based on a national average utility cost of 1.5 cents per gallon of water and wastewater, saving 300,000 gal. of water would reduce the university's water/wastewater utility bill by $4,500 a year.

Utilities account for about 30 percent of an office building's expenses, according to Flex Your Power, California's energy-efficiency marketing and outreach campaign. A 30-percent reduction in energy consumption can lower operating costs by $25,000 a year for every 50,000 sq ft of office space.

Although the energy used for plumbing fixtures is small compared with that used for HVAC equipment and major appliances, engineers should be mindful of the energy implications of plumbing fixtures in the overall sustainability picture. Products such as solar-powered faucets and energy-efficient hand dryers can give restroom users a positive impression and a visible representation of a building's overall sustainable efforts as opposed to water heaters and other building systems that may be saving substantially more water and/or energy, but cannot be seen by the public.

The public is taking greater notice of how companies and facilities expend water and energy, and users and communities alike are holding building owners accountable for their use of precious local resources. Engineers need to stay abreast of water- and energy-efficiency options in the restroom to keep operating costs in line and help buildings meet LEED standards.

Jim Allen, LEED AP, is the water-efficiency manager for Sloan Valve Co.

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LEED Basics

The LEED Green Building Rating System represents the U.S. Green Building Council's effort to provide a national standard to determine what constitutes a “green building.” Through its use as a design guideline and third-party certification tool, it aims to improve occupant well-being, environmental performance, and economic returns of buildings using established innovative practices, standards, and technology.

Application for LEED credits starts with architects, engineers, and other building designers. Through the use of carefully calculated floor plans, environmentally friendly building materials, energy-efficient products, and innovative system designs, buildings can obtain a high-ranking LEED certification. The certification process can produce buildings that not only are great environments to be in, but save energy and resources every day that they are in use.

Numerous building-construction products and fixtures can help earn credits for LEED certification. Through proper planning and the purchase of efficient products, water and energy use in buildings can be decreased significantly.

Benefits to Engineers

An engineer reaps many benefits by being involved with the design team from the start of a project. For instance, early involvement offers engineers insight into design issues and sustainability goals and encourages them to ask questions. Additionally, an engineer can better evaluate bid documents and provide early estimates that allow the entire team to plan and anticipate costs more accurately. Having an idea of what to expect also allows time for the development of new procedures and, if needed, allows time to train and educate subcontractors.

Developing knowledge of LEED criteria is helpful in meeting requirements on projects undergoing LEED certification; recruiting clients, such as government agencies, colleges, and major businesses that use LEED; delivering a quality product; and gaining a competitive edge in the growing green-building marketplace.