Water efficiency is the amount of water an appliance uses per minute, typically measured in gallons per minute in the US, and involves using the least water necessary to accomplish a given task. This differs from water conservation, which involves changing consumer habits to minimize water consumption. Both are important for sustainability, as both improve how we use our water.
Bathroom appliances such as toilets, sinks, or showers are utilities that most people would not be willing to completely cut out of their life. Instead, we focus on maximizing the water efficiency of appliances like sinks, shower heads, or toilets, which can save gallons of water without relying on consumers to change their daily habits. This saved water cuts down on additional energy costs for transporting the fresh water from the source to your home or business, transporting the used water to a processing plant, and filtering the waste water. Examples of water efficient alternatives to bathroom appliances are low flow shower heads (1.6-2.5 gpm), low flow sinks (1.5 gpm), and water efficient commercial toilets (1.6 gallons per flush).
Water efficiency is measured in flow rate with gallons per minute (gpm). Typically, this measurement can be found on a faucet or showerhead or evaluated before purchase. However, gpm varies depending on water pressure, so just because a showerhead is designed to send 1.6 gpm, it may send more or less depending on the pressure.
To measure water efficiency, take a gallon container and place it under the hose, faucet, or sink. Turn on the appliance and start a timer. Depending on how quickly the container is filled up, one can measure the flow rate. For example, if the contained fills up in fifteen seconds, then the gpm of the appliance is 4 gpm. In this way, one can get a true measurement of flow rate which takes into account local water pressure.
The best way to be more water efficient is to buy water efficient appliances that have a low flow rate. This will improve the use of water in the business and save money in the long term. Another way is to implement policies focused on water efficiency and conservation. Turning off running sinks, using washing machines when they are full, and stopping other wasteful practices can help.
Finally, certain devices exist that make sinks more efficient. Aerators are a cheap way to save up to 66% more water on sinks. By installing these devices, the flow becomes more dispersed, which improves the surface-to-water ratio and allows one to do more with the available water.
The EPA’s WaterSense certification is a volunteer program that certifies businesses and appliances that meet their standards. Typically, these appliances use 20% less water than the normal standard, making them more efficient while doing the same job.