Through a combination of strategic planning, project execution and conservation efforts, EPA has been able to reduce water intensity over the past several years.
Water management plans help individual facilities set long- and short-term water conservation goals. EPA currently has 20 signed water management plans.
Following are the top 10 water best management practices that EPA has implemented to reduce water use at facilities throughout the agency.
Metering and measuring facility water use help to analyze saving opportunities. This also assures the equipment is run correctly and maintained properly to help prevent water waste from leaks or malfunctioning mechanical equipment.
A cooling tower at EPA’s Environmental Science Center in Fort Meade, Maryland
Cooling towers provide air conditioning for laboratories and are large consumers of water. Cooling tower operations can be optimized by carefully controlling the ratio of water discharged (blowdown) to water evaporated. The ratio of evaporation to blowdown is called the cycle of concentration. For maximum water efficiency, cooling towers should be operated at six or more cycles of concentration. Metering water put into and discharged from the cooling tower ensures the cooling tower is operating properly and can help identify leaks or other malfunctions.
The U.S. Department of Energy established federal water-efficiency standards in the 1990s. Prior to that, most EPA facilities had inefficient sanitary fixtures. For example, toilets used 3.5 gallons per flush (gpf). Nearly all EPA laboratories have since installed water-efficient fixtures, many of which have earned EPA’s WaterSense ® label for efficiency and performance. These include:
Faucet aerators flowing at 0.5 gpm, well below the 2.2 gpm federal standard, have also been installed in most laboratories.
Single-pass cooling circulates a continuous flow of water just once through the system for cooling purposes before it goes down the drain. EPA strives to eliminate single-pass cooling in its laboratories. Instead, facilities have air-cooled or recirculating chilled water systems.
Planting native and drought-tolerant plant species minimizes the need for supplemental irrigation. Landscape water use can also be reduced 10 to 20 percent by having an irrigation water audit. EPA selects audit professionals certified through a WaterSense labeled program. WaterSense labeled weather-based irrigation controllers or soil moisture sensors are used to water only when plants need it.
Steam sterilizers use cooling water to temper steam condensate discharge from the sterilizer to the laboratory drain. Many older sterilizers discharge a continuous flow of tempering water to the drain, even when it is not needed. EPA has retrofitted sterilizers with a tempering water control kit or replaced old steam sterilizers with models that only apply tempering water when needed.
EPA’s Great Lakes Toxicology and Ecology Division Laboratory pumps water from Lake Superior in Duluth, Minnesota.
Several EPA laboratories require water for aquatic culture research. In some cases, culture water is pumped into laboratory specimen tanks from local bodies of water, such as lakes or bays. It is then discharged into the sewer or treated and returned to the body of water.
Up to 10 percent of a laboratory’s water consumption can be related to the multi-step process of generating deionized (DI) purified water through reverse osmosis (RO). Water savings can be achieved by carefully regulating purified water generation rates to meet laboratory demand and making sure that systems are sized accordingly.
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A rooftop rainwater recovery system at EPA’s Region 7 Science and Technology Center in Kansas City, Kansas
Recovery systems capture rainwater from the roof and redirect it to a storage tank. This water is used for flushing toilets, supplying cooling towers and irrigating the landscape.
Air conditioning units produce condensate water from the cooling coils. Many EPA laboratories are capturing this water for use as cooling tower make-up water.
For more information on water-saving best practices, please see the resources available from:
