Water meters measure the cumulative volume of water passed through it in cubic metres of water. They are primarily classed by size and to ensure meter accuracy the flow rate must be within a specific range. The volume of water with vary with the diameter of pipe but with a 1 inch pipe (25mm) the ranges for each class are as follows:
- Class A – 140 to 350 litres per hour
- Class B – 70 to 280 litres per hour
- Class C – 35 to 52 litres per hour
- Class D – 26 to 40 litres per hour
There are 3 types of water meters:
- Single Jet – water flows directly onto an impeller turbine.
- Multi Jet – water flows on to multiple points on the impeller turbine and which aid reliability and longevity.
- Volumetric – also known as positive displacement meters. They measure water volume by splitting the water into set fixed-volume amounts then counting the number to determine the total volume.