How Many Types of Water Meters Are There

How Many Types of Water Meters Are There? Do You Know What Their Symbols Mean?

Overview

Since British inventor Thomas Cloos developed the first true instrument-type balance tank water meter in 1825, the evolution of water meters has spanned nearly two centuries. In China, the use and production of water meters began relatively late. Starting in 1955, municipal water companies in cities such as Shanghai, Beijing, Tianjin, Nanjing, Wuhan, and Guangzhou gradually began manufacturing water meters.

From the 1990s onward, water meter technology in China has progressed from horizontal helix-type meters, multi-jet dry-type rotary meters, and wet-type rotary meters to more advanced models such as remote-reading meters integrated with centralized data collection systems, IC card meters, TM card meters, and coded meters. This marks a new phase in the development of China’s water meter industry.

A water meter is an instrument used to measure water flow, most commonly for cumulative volume measurement. When selecting a water meter specification, one should first estimate the typical flow rate and range of usage. Then, choose the model whose nominal flow rate most closely matches the estimated value as the preferred option.

1. Types of Water Meters

1.1 By Measurement Principle: Velocity-Type and Volumetric-Type Water Meters

Velocity-Type Water Meter: Installed in closed pipelines, these meters contain a moving element driven directly by the velocity of water flow. Typical examples include rotary vane meters and helix-type meters. Rotary vane meters can be further divided into single-jet and multi-jet types.

Volumetric-Type Water Meter: Installed in pipelines, these meters consist of chambers with known volumes that are sequentially filled and emptied, driven by fluid flow. Also known as fixed-volume discharge meters, they typically use a piston-type structure.

1.2 By Nominal Diameter: Small-Caliber and Large-Caliber Water Meters

Water meters with a nominal diameter of 40 mm or less are classified as small-caliber.

Water meters with a nominal diameter of 50 mm or more are classified as large-caliber.

This classification also corresponds to connection types: meters ≤40 mm typically use threaded connections, while those ≥50 mm use flanged connections.

1.3 By Installation Orientation: Horizontal and Vertical Installation

Refers to the direction of water flow relative to the horizontal plane during installation.

On the meter dial, “H” indicates horizontal installation, and “V” indicates vertical installation.

1.4 By Medium Temperature: Cold Water and Hot Water Meters

The dividing line is 30°C.

Cold Water Meter: For media with a temperature range of 0°C to 30°C.

Hot Water Meter: For media with a temperature range of 30°C to 90°C, 130°C, or 180°C, depending on the model.

Note: Requirements vary slightly by country; in some regions, cold water meters may be rated up to 50°C.

1.5 By Operating Pressure: Standard and High-Pressure Water Meters

Standard Water Meter: Nominal pressure typically 1 MPa.

High-Pressure Water Meter: Designed for maximum operating pressures above 1 MPa, mainly used for measuring water in industrial applications such as oilfield injection pipelines.

1.6 By Counter Immersion: Wet-Type, Dry-Type, and Liquid-Sealed Water Meters

Wet-Type Water Meter: The counter is immersed in water; the glass cover bears water pressure, and the transmission between sensor and counter is gear-driven. Water quality may affect dial readability over time.

Dry-Type Water Meter: The counter is isolated from water; the sensor and counter are separated structurally, and the glass cover is not exposed to water pressure. Transmission is typically magnetic.

Liquid-Sealed Water Meter: The counting wheels or entire counter are sealed with a specially formulated liquid (e.g., glycerin). This prevents external water quality from affecting readability, while other structural features are similar to wet-type meters.