Changes

[[Image:domestic water meter.jpg|thumb|right|300px|Domestic water meter. Drawing: WHO.]]

Water meters, in combination with public standposts or domestic connections, provide the means to charge fees according to the volume of water delivered, and to regulate water use via tariffs. Water meters consist of a device to measure flow, and a protective housing with an inlet and an outlet. A strainer over the inlet keeps larger particles out of the system. There are many types of water meter, but for ordinary domestic or public standpipe use, turbine meters are most common. The vane wheel and the counting device of a water meter can be coupled magnetically or directly. Magnetic coupling has the advantage that the counting device can be completely sealed and no water, silt or algae will get in. A shut-off valve is normally installed on both sides of the meter to allow for servicing.