Module 4: Water Efficiency

Common Options for Reducing Domestic Water Use

Lavatory faucets

The three main types of lavatory faucets found in institutional/commercial buildings include conventional faucets, self-closing, and infrared. Conventional faucets have flow restrictors installed that reduce the amount of water they use. The flow restrictors can be either aerators or laminar-flow devices. Self-closing faucets are mechanically controlled to close after a certain amount of time or volume of water has passed. Infrared faucets are electronically controlled to run for a preset amount of time when activated. Both self-closing and infrared faucets are beneficial for high-use water areas where a faucet may accidentally be left on.

Water-efficient options for lavatory faucets include aerator or laminar-flow devices and reprogramming self-closing and infrared faucets. Aerators for faucets are available in rates as low as 0.5 gpm. Self-closing and infrared faucets can be reprogrammed to use 0.2 gallons per cycle. Table 4 shows the percent reduction possible for water-efficient lavatory faucets.

Table 4

Fixture	Percent Reduction from 2.2 gpm or 0.25 gal/cycle (per unit)
0.5 gpm aerator	77%
1.0 gpm aerator	55%
1.8 gpm faucet	18%
0.2 gal/cycle self-closing	20%

“An estimated 10 percent savings on sensor-operated faucets can be calculated for LEED. Sensor-operated and self-closing faucets help to reduce water use in high-traffic areas where people may inadvertently leave faucets turned on.” (LEED EB reference guide)

Showerheads

Institutional/commercial buildings that provide showers for their occupants can realize water savings through the use of efficient showerheads. The EPAct 1992 standard for showerheads is 2.5 gpm (at 80 psi). More-efficient showerheads are rated at 2.0 gpm (and below) which can reduce water use an additional 20% from the EPAct 1992 standard of 2.5 gpm.

At least two-thirds of the world will live in water-scarce regions by 2025.

Staff breakrooms/kitchens

Staff breakrooms or kitchens use water in sinks and dishwashers. Sinks are used for supplying water needed for food and drink preparation and for dishwashing. The EPAct standard for non-lavatory faucets is 2.2 gpm. There is no EPAct standard for dishwashers, but water use can range from 7 to 12 gallons per use.

Low-flow faucets and aerators for kitchen sinks are available in a flow rate of 1.8 gpm, or approximately 18% below the 2.2 gpm EPAct standard. Reducing the flow rate below this level is not advised due to the need for water for food preparation and drinking. Restricting the flow rate will not reduce the need for the water, just the time it takes to fill a container. Dishwashers can be replaced with more-efficient units that use as little as 4 gallons per use or approximately one-third of what an older dishwasher can achieve.

Figures 4 and 5 show the difference in water flow for aerators and laminar-flow devices. Laminar-flow devices are preferred for use in hospitals because there is no mixing of air and water (which can spread disease). Laminar-flow devices and aerators are similarly priced and are available in the same flow rates.

Figure 4: Aerator	Figure 5: Laminar Flow