Different requirements for different types of faucets and applications
In the U.S., the Energy Policy Act of 1992 (EPAct 92) and subsequent rulings by the U.S. Department of Energy (DOE) set the maximum continuousflow faucet rate of flow for both commercial and residential faucets at 2.2 gallons per minute (gpm), or 8.3 Litres per minute (Lpm), when measured at 60 pounds per square inch (psi) of flowing water pressure. EPAct 92 also set the maximum water use for metering faucets at 0.25 gallons per cycle (gpc), or 0.95 Litres per cycle (Lpc); metering faucets are not subject to a maximum flow rate, however.
What is the difference between the two types?
Continuous Flow Faucet:
May be manually activated or sensor-activated
Faucet closure may be either done manually OR by de-activating a sensor by removing hands from faucet flow
Efficiency determined by a maximum flow rate
May be mechanically activated or sensor-activated
Faucet closure occurs when the specified water volume is reached
Efficiency determined by the maximum volume of water released during a single activation cycle
Later in the 1990s, the ANSI national product standard, ASME A112.18.1, went further and lowered the maximum flow rate for all public flowing faucets to 0.5 gpm (1.9 Lpm). The maximum flow rate for all other washroom and kitchen faucets in the U.S. remained at 2.2 gpm, or 8.3 Lpm. The terms public and private are defined in the U.S. model plumbing codes (International Plumbing Code and Uniform Plumbing Code) generally as follows:
Private Use: Applies to plumbing fixtures in residences and apartments, to private bathrooms in hotels, hospitals, and health care facilities, and to restrooms in commercial establishments where the fixtures are intended for the use of a family or an individual.
Public Use: Applies to plumbing fixtures that are not defined as private or private use.
In 2007, the U.S. EPA's WaterSense program, which is a voluntary program, set the maximum flow rate for residential lavatory (flowing) faucets at 1.5 gpm (5.7 Lpm). WaterSense does not label or set a maximum flow rate for commercial lavatory faucets. WaterSense also does not label residential or commercial kitchen faucets, which are often used to fill vessels, such as pots, jugs, sinks, coffee makers, etc., where reducing the flow rate does not reduce the total volume of water used but simply extends the time required to complete the task.