Best Management Practices

Overview

WaterSense has developed WaterSense at Work, a compilation of water-efficiency best management practices, to help commercial and institutional facilities understand and better manage their water use, help facilities establish an effective water management program and identify projects and practices that can reduce facility water use.

By implementing water-efficient best management practices, commercial and institutional facilities have an opportunity to:

• Achieve cost savings
• Increase competitive advantage
• Reduce risks associated with water scarcity
• Demonstrate leadership
• Access opportunities in the green building marketplace

All facilities should review Sections 1 and 2 to better manage and reduce their water use. Sections 3 through 8 address opportunities associated with specific equipment and systems used at commercial and institutional facilities. Each section has tips to improve the operation, maintenance, and educate others on proper use. Next it provides retrofit and replacement options to make these products and equipment more water efficient while considering the impact of product performance. Each section ends with detailed guidance for determining how much water a facility could save by implementing one or more of the recommended practices.

• Getting Started
• Water Use Monitoring and Education
• Sanitary Fixtures and Equipment
• Commercial Kitchen Equipment
• Outdoor Water Use
• Mechanical Systems
• Laboratory and Medical Equipment
• Onsite Alternative Water Sources

Monitoring and Education

Actively monitoring water use and effectively educating facility staff, building occupants, employees, and visitors about facility water use and water management planning goals are key components of properly managing and reducing facility water use. Monitoring and education set the stage for the relative success of a facility's water management program. They provide the ability to track and measure progress to increase awareness and build support for specific projects or user behavior changes.

In this section, learn more about:

• Metering and submetering
• Leak detection and repair
• User education and facility outreach
• Codes, standards and voluntary programs for water efficiency

Sanitary Fixtures and Laundry

Sanitary fixtures and equipment in restrooms and laundries can account for nearly 50 percent of total water use within a facility. Depending on the type of facility and number of occupants and visitors, sanitary fixtures and equipment can provide significant opportunities for water and energy savings, particularly in older buildings with inefficient fixtures and equipment.

Section 3: Sanitary Fixtures and Equipment of WaterSense at Work provides information on equipment that nearly every type of commercial and institutional facility has including:

• Toilets
• Urinals
• Faucets
• Showerheads
• Laundry equipment

Learn how a hotel in San Antonio saved water and money by retrofitting their bathrooms with water efficient fixtures.

Kitchen Equipment

In restaurants, water use in the kitchen can account for nearly 50 percent of the facility's total water use. Several other commercial and institutional sectors, including hospitals, offices, schools, and hotels, also have substantial kitchen water use that accounts for upwards of 10 to 15 percent of the facility's total water use. The figure below shows the percentage of facility water use that is attributed to kitchens for various commercial facility types.

Water use will vary depending upon the scope and scale of the kitchen's operations. Larger kitchens found in food service establishments may use water more intensely in almost every aspect of their operation than smaller kitchens with less output. In most commercial kitchens, the commercial dishwasher and pre-rinse spray valve account for over two-thirds of the water use.

Water-efficient commercial equipment can result in both significant water and energy savings. Newer technologies and better practices are available that can significantly reduce commercial kitchen equipment water and energy use. For example, ENERGY STAR® qualified dishwashers, ice machines, and steam cookers are at least 10 percent more water efficient and 15 percent more energy efficient than standard models, with some models saving significantly more.

Section 4: Commercial Kitchen Equipment of WaterSense at Work provides an overview of and guidance for effectively reducing the water use of:

• Commercial ice machines
• Combination ovens
• Steam cookers
• Steam kettles
• Wok stoves
• Dipper wells
• Pre-rinse spray valves
• Food disposals
• Commercial dishwashers
• Wash-down sprayers

Learn how three restaurants in Chicago, Illinois; Omaha, Nebraska; and Washington, D.C.; saved water and energy by implementing several best management practices.

Outdoor Water Use

Outdoor water use can account for between 5 and 30 percent of a facility's total water use, as shown below. Better landscaping and pool maintenance practices and more efficient irrigation equipment can provide opportunities for significant water savings in commercial settings.

Facilities that own or maintain their surrounding landscape can use significant amounts of water to maintain and irrigate the landscape. The amount of water use is dictated by the size and design of the landscape as well as the local climate and facility type. Facilities with large areas of maintained landscape, such schools, can use as much as 30 percent of their water to maintain the health and quality of the landscape. Outdoor water use can be controlled and minimized with proper landscape design and maintenance of any supplemental irrigation systems.

Many facilities also consume significant amounts of water for the operation and maintenance of pools and vehicle washing stations on site. Pools can be managed by reducing water loss associated with evaporation, filter cleaning, mineral buildup control, leaks, and splashing. Vehicle washing stations can save at least 50 percent of the water used through reclaiming and reusing water.

Section 5.0: Outdoor Water Use of WaterSense at Work provides an overview of and guidance for effectively reducing the water use associated with:

• Landscaping
• Irrigation
• Commercial pool and spa equipment
• Vehicle washing

Learn how the Granite Park office complex in Plano, Texas, saved nearly 12.5 million gallons of water by increasing the efficiency of the irrigation system.

Mechanical Systems

Mechanical systems are used in nearly every type of commercial and institutional facility to provide building heating and cooling. Some also use mechanical systems to cool specific pieces of equipment, such as vacuum pumps, X-ray equipment, and ice machines. Levels of water use vary widely for different commercial facility types, amounting to as much as 30 percent of the total water use within a facility as shown below.

Energy- and water-efficiency measures should be implemented together throughout the facility to decrease the heating and cooling load of the entire system. Increasing the efficiency of the overall systems results in significant reductions in energy and water usage while creating cost savings.

To reduce mechanical system water use, facilities should first eliminate single-pass cooling or reuse that water, then evaluate cooling towers, chilled water systems, and other heating systems to maximize efficiency. In some cases, single-pass cooling can be the single largest water user at a facility, using approximately 40 times more water to remove the same heat load than a cooling tower operating at five cycles of concentration. Ensuring that cooling towers and chilled water systems are properly maintained will minimize the amount of cold water needed to remove heat from equipment. Water use can also be optimized in boiler and steam systems by returning steam condensate back into the system.

Section 6: Mechanical Systems of WaterSense at Work provides an overview of and guidance for effectively reducing the water use of:

• Single-pass cooling
• Cooling towers
• Chilled water systems
• Boiler and steam systems

Learn more about how the U.S. Environmental Protection Agency's Mid-Continent Ecology Division Laboratory in Duluth, Minnesota, eliminated single-pass cooling and reduced its potable water use by 90 percent .

Laboratory and Medical Equipment

From dental and doctor's offices to large general hospitals, veterinary clinics, and research laboratories, medical and laboratory facilities have special operations and equipment. These systems can consume a significant amount of water through water purification, sterilization, photographic and X-ray processes, and vacuum systems. As shown below, equipment such as steam sterilizers and reverse osmosis systems can account for 5 percent of a laboratory's total water use. Hospitals can attribute more than 15 percent of their total water use to laboratory and medical equipment, including steam sterilizers and X-ray processing equipment.

Many older pieces of medical and laboratory equipment use single-pass cooling continuously, but newer technologies and better practices are available that can significantly reduce this water use. Converting to digital equipment can eliminate some of this water use entirely.

Laboratories and medical facilities may face unique challenges because of the high quality of the water required for their equipment to maintain purification and health and safety standards. These standards can limit the types of technologies that can be utilized, but many improvement opportunities still exist. Water efficiency alone will not be a driver in the choice of technologies or processes in these facilities, but it should be a consideration after other requirements have been met.

Section 7: Laboratory and Medical Equipment of WaterSense at Work provides an overview of and guidance for effectively reducing the water use of:

• Water purification
• Vacuum pumps
• Steam sterilizers
• Glassware washers
• Fume hood filtration and wash-down systems
• Vivarium washing and watering systems
• Photographic and X-ray equipment

Learn how Providence St. Peter Hospital in Olympia, Washington, saved 31 million gallons of water by installing water-efficient laboratory and medical equipment and implementing many additional best management practices described in WaterSense at Work.

Alternative Water Sources

Facilities can further reduce potable water use by taking advantage of onsite alternative water sources. An onsite alternative water source is the water discharge from one application or process that is captured, treated, and utilized in another application. These onsite alternative water sources can vary greatly in quality and must be carefully matched with an appropriate end use.

Potential onsite alternative water sources include:

• Rainwater/stormwater
• Foundation drain water
• Treated gray water
• Condensate from air handler equipment
• Filter and membrane (e.g., reverse osmosis system) reject water
• Cooling equipment blowdown

Although discharge from single-pass cooling systems can be a suitable onsite alternative water source, facility managers should first consider eliminating single-pass cooling, as described in Section 6.2: Single-Pass Cooling. If elimination is not feasible, then consider reuse of the discharge water for another purpose.

General considerations for reuse of onsite sources of water include the quality constraints of the source and the potential types of treatment that may be needed to meet the quality needs of the proposed end use. Every situation is different, but many resources provide guidance on typical considerations.

Section 8: Onsite Alternative Water Sources of WaterSense at Work describes potential uses of onsite alternative water including:

• Irrigation
• Cooling tower make-up water
• Toilet and urinal flushing
• Make-up water for decorative ponds, fountains, and waterfalls
• Processes or other uses not requiring potable water
• Fume hood scrubbers

Learn more about how the University of Texas at Austin used onsite alternative water sources to reduce its potable water use by more than 33 percent.