Water meters are used to measure the volume of water used by residential and commercial building that are supplied with water by a public water supply system. Water meters can also be used at the water source, well, or throughout a water system to determine flow through a particular portion of the system. In most of the world water meters measure flow in cubic metres (m3)

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There are several types of water meters in common use. The choice depends on the flow measurement method, the type of end user, the required flow rates, and accuracy requirements.

There are two common approaches to flow measurement, displacement and velocity, each making use of a variety of technologies. Common displacement designs include piston and disc meters. Velocity-based designs include single- and multi-jet meters and turbine meters.

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There are also non-mechanical designs, for example electromagnetic and ultrasonic meters. Most meters in a typical water distribution system are designed to measure cold potable water only. Specialty hot water meters are designed with materials that can withstand higher temperatures. Meters for reclaimed water have special lavender register covers to signify that the water should not be used for drinking.

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Additionally, there are electromechanical meters, and Energy Calculation Meters. Mechanical water meters normally use a reed switch, hall or photoelectric coding register as the signal output. After processing by the microcontroller unit (MCU) in the electronic module, the data are transmitted to the LCD or output to an information management system.