A water meter is a device used to measure the volume of water usage. This article provides an overview of technical aspects of water meters. The worldwide prevalence of metering as well as its economic benefits and costs are covered in the separate article on water metering.

In many developed countries water meters are used at each residential and commercial building in 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 that portion of the system. Water meters typically measure and display total usage in cubic feet, cubic meters or US gallons on a mechanical or electronic register. Some electronic meter registers can display rate-of-flow as well as total usage.

There are several types of water meter in common use. Selection is based on different flow measurement methods, the type of end user, the required flow rates, and accuracy requirements.

In North America, standards for manufacturing of water meters are made by theAmerican Water Works Association.