Water metering is the process of measuring water use.

In many developed countries water meters are used to measure the volume of water used by residential and commercial buildings that are supplied with water by a public water supply system.

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.

A water flow meter is an instrument capable of measuring the amount of water passing through a pipe. Several water flow meter technologies are available for selection depending on the water measurement applications, budgetary terms, and maintenance requirements. Each of these water flow meter types has a unique principle of operation, overall cost-of-ownership, and specific application benefits.

The benefits of metering are that:

1. In conjunction with volumetric pricing it provides an incentive for water conservation.

2. It helps to detect water leaks in the distribution network, thus providing a basis for reducing the amount of non-revenue water;

3. It is a precondition for quantity-targeting of water subsidies to the poor.

Velocity water meters

A velocity-type meter measures the velocity of flow through a meter of a known internal capacity. The speed of the flow can then be converted into volume of flow to determine the usage. There are several types of meters that measure water flow velocity, including jet meters (single-jet and multi-Jet), turbine meters, propeller meters and mag meters. Most velocity-based meters have an adjustment vane for calibrating the meter to the required accuracy.

Prepaid water meters

Meters can be prepaid or postpaid, depending on the payment method. Most mechanical type water meters are of the postpaid type, as are electromagnetic and ultrasonic meters. With prepaid water meters the user purchases and prepays for a given amount of water from a vending station. The amount of water credited is entered on media such as an IC or RF type card. The main difference is whether the card needs a contact with the processing part of the prepaid water meter. In some areas a prepaid water meter uses a keypad as the interface for inputting the water credit.