Differences Between Water Meters and Flow Meters

Differences Between Water Meters and Flow Meters

Water Meters and Flow Meters

It is not surprising to find many people use the terms flow meter and water meter interchangeably. This is because the two phrases are misconstrued by most to mean the same. However, while water meters can perform as flow meters, the latter has additional functions.

Essentially, water meters measure the water volume when the water is conveyed through a meter. Water flow meters are utilized to measure the speed the water flows at when conveyed through the meter.

Another major difference is that while water meters are used exclusively for measuring water, flow meter applications may also include oil, honey, milk, and other liquids for industrial purposes. Also, flow meters are applicable when measuring gas flow rate.

Types of Water Meters and Flow Meters

Mechanical: A mechanical type of water flow meter utilizes moving parts such as an impeller or piston.

Electromagnetic: There are no moving parts in this type of meter, and it utilizes electromagnetic waves to denote the speed and the water volume.

Ultrasonic: there are ultrasonic waves that move through water as it flows. That is how this type of meter measures water volume and flow. There are two types of ultrasonic meters.

Transit time meters: Essentially, sound travels slower when going against the flow of water. Conversely, it travels faster when going with the flow. As such, two transducers are placed on each side of the pipe to measure the flow and volume of the water as it passes through.

Doppler Meters: these measure sound frequency as it bounces back from an object that is moving. Therefore, this water flow meter helps measure the flow and volume using bubbles or impurities of water as they bounce back. However, these flow meters cannot be used if the water is clean as the measurement will not be accurate.

How Water and Flow Meters Function

There are various subcategories of electromagnetic, mechanical, and ultrasonic flow and water meters. However, they all include the following components.

  •  A sensor is used to detect water flow.
  •  A transducer that helps convert as well as transmit a flow signal.
  •  A counter is used to track water volume as it is conveyed through the sensor. The counter uses the pulses sent via the meter and determines the volume and the flow rate of the water.

Additional Differences Between Flow Meters and Water Meters

  • A water meter has an exclusive function as it is used for billing purposes. If AMR/AMI technology is used in water meters, accurate, real-time, and online data is shown in the meter. This saves the expense and time of reading the data manually.
  • Water flow meters have a variety of functions in terms of monitoring flow rate. For instance, in gas applications, the flow meters are a necessity and help detect leaks and blockages that may cause lethal consequences.
  • Water meters have to accurately measure quantity or volume; the high range and the low range measurement. The average between the two determines what reading is correct.
  • The accuracy of a flow meter is determined by linearity or having designed limits all the time. Therefore, the same results should be shown at all times when measured under similar conditions. Essentially, linearity and repeatability are not that important when using water meters.


In conclusion, while the design of water and flow meters is similar, the differences mentioned above show their difference in function. As mentioned, if you consider water billing, you are referring to a water flow meter. However, if considering a device that measures both gas and liquid, you are referring to flow meters. Also, if you need to measure the quantity of water, what you require is a water meter. On the other hand, velocity measurement is a preserve of the flow meter.

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