watermeter

A water meter, also written as watermeter, is a device fitted on a water supply pipe to measure the volume of water that passes through for billing, usage monitoring, and water management. Utilities rely on meters to bill customers and to track consumption.

There are several technologies commonly used: positive displacement meters (including piston and diaphragm types) that measure by counting discrete volumes; turbine meters that rely on a rotating wheel; and velocity or non-contact meters such as ultrasonic and electromagnetic types.

In positive displacement meters, the movement of internal chambers displaces a fixed amount of water with each cycle, and the register tallies cycles. Turbine meters use a rotor driven by flow; ultrasonic meters measure transit times or Doppler shifts; electromagnetic meters measure voltage induced by conductive water in a magnetic field. Each type has different advantages for residential, commercial, or industrial use.

Most meters report volume in cubic meters (m3) or gallons. The dial may show a long main register plus smaller dials for tenths and hundredths, or provide a pulsed output for remote reading.

Meters are installed on the incoming service line, often with shut-off valves and backflow protection. They must be accessible, protected from freezing, and periodically inspected and tested for accuracy. Tamper-evident seals may be used.

Modern meters often support automated or remote reading (AMR/AMI), allowing utilities to collect usage data without on-site visits. Customers can also read the meter manually, especially when reporting leaks or outages.

Meters are designed to meet national or international standards (for example, AWWA in North America, ISO or OIML internationally). Accuracy can vary by flow rate, temperature, and installation, but meters are typically certified within specified accuracy classes. Common issues include leaks, air in the line, or faulty seals leading to over- or under-registration. proper sizing, installation, and regular verification help ensure fair billing and accurate water management.