All About Water Flow Meters

A water flow meter is a device that measures the flow of water in a pipe, hose, or other manner of conveyance. It is a subset of flow meters, which are used for a wide variety of liquids, gases, and steam, and many flow meter technologies are suited to water. Each technology offers something unique for different types of applications.

Key Takeaways

• Positive displacement flow meters are generally not the best choice for water, since they need viscous or lubricating media to protect their gear mechanisms.
• Magnetic flow meters only work with water that has sufficient minimum conductivity, so the properties of your water narrow the technologies that will work.
• Industrial water flow meters run 24-7 and need accuracy, durability, and the least possible maintenance, while residential meters are small and inexpensive.
• Technologies with no moving parts (magnetic, ultrasonic, vortex, Coriolis, and differential pressure) are a good place to start for high flow rates.
• Clamp-on water flow meters are almost exclusively ultrasonic, because the ultrasonic measuring principle does not require contact with the media.

How Do You Measure Water Flow in a Pipe?

The device that can measure the flow of water in a pipe is called a water flow meter. Flow meters, used for a wide variety of liquids, gases, and steam, are in use all over the world sensing the flow of water in a variety of applications and processes. There are many different flow meter technologies that are suitable to measuring the flow of water in a pipe. Each flow meter technology type offers something unique that allows them to be best suited for different types of applications.

What Does a Water Flow Meter Do?

A water flow meter can measure, monitor, and help to control the flow of water through a pipe, hose, or other manner of conveyance. It can provide a continuous reading of the water flow rate. Many flow meters for water can also perform other functions essential to different applications, like batching precise amounts into a process or totalizing the total volume of flow for a certain specified time frame.

What is the Difference between a Flow Meter and a Water Flow Meter?

A water flow meter is simply a subset type of flow meters. Flow meters can be used with a wide variety of different media besides water. So, all water flow meters are flow meters, but not all flow meters are water flow meters, as some flow meters are not designed for use with water.

What are the Types of Water Flow Meters?

Based on the different flow meter technology types, there are many flow meter technologies that can handle the measurement and monitoring of water. As a generalization, the only flow meter technology type that is not the best choice for water is positive displacement flow meters, as they generally require viscous media or media with lubricating properties to protect the gear mechanisms.

The other most popular flow meter types that typically are used for water are listed below. Visit our flow meter technology articles to learn more about any specific water flow meter technology type.

How Do I Choose a Water Flow Meter?

Start with the water itself: its properties decide which water flow meters will work for your application. Then weigh the application variables: temperature, whether you need switching, alarm, totalizing, or batching, how wide a range of flow rates the meter must handle (known as turndown), turbulent flow, indoor or outdoor installation, and vertical or horizontal flow direction.

Each technology type varies in its ability to function correctly with different water properties. For example, magnetic flow meters cannot process water that doesn't have a sufficient minimum conductivity. So even though magnetic flow meters can be compatible with water, they are only compatible with certain types of water.

It is important to understand how the properties of the water to be measured determine which water flow meters will work for your application. Other examples of water types would be water with particulate matter, water with bubbles, aggressive water, salt water, pure water, deionized water, potable water, distilled water, dirty water, process water, and many other characteristics that can determine the appropriate choice of a flow meter for a particular application. Another consideration would be the temperature of the water in the application. Certain technologies and specific flow meter models are more limited in their temperature capacities than others. There are many other factors than just the media that go into choosing the correct water flow meter.

Where are Water Flow Meters Used?

Based on where they are being used, there are three main usage categories of water flow meters: industrial, municipal, and residential/personal. Each of these broad application areas can help determine which types of water flow meters are appropriate for the exact need.

What are the Differences between Industrial, Municipal, and Commercial/Residential Water Flow Meters?

Industrial water flow meters are built for accuracy, durability, and the lowest possible maintenance, because they usually run around the clock in demanding processes with high pressures and temperatures. Municipal water meters are built for billing accuracy. Residential or personal use water flow meters are usually small, inexpensive, and not designed for heavy-duty, frequent usage.

Because industrial processes often require a great deal of precision for the process or product, flow meter accuracy is usually a prominent consideration for industrial applications, as opposed to someone who just wants to know how much water their garden hose may be consuming. Industrial flow meters also need to be durable and reliable. Industrial processes can be demanding as far as high pressures, high temperatures, and the continuous operating time that the flow meter is in service. While a cheap little plastic flow meter with a simple readout of flow may suffice for a garden hose that is in service a few minutes or hours a week, industrial water flow meters are usually installed in heavy-duty processes that run 24-7.

Because shutting industrial processes down usually means less product is produced and less money is made, industrial water flow meters need to offer the lowest amount of maintenance possible. Again, while it costs a homeowner nothing to clean any accumulating gunk out of a little plastic flow meter, it can cost businesses thousands of dollars to shut down processes, as it often means removing whole sections of process line for inline flow meters. This is the reason that insertion and clamp-on flow meters are used in certain applications and are becoming more popular, as they reduce or eliminate the downtime required for any maintenance or calibration.

Industrial water flow meters may also need to perform additional tasks that are not possible with other flow meter types. For example, industrial processes may require totalizers that calculate exactly how much water was used in total or for a predetermined time frame. Batching control is also a common need in industrial applications, where the flow is stopped after a certain quantity has been dispensed into the process.

Municipal flow meters also require accuracy. When someone comes to read your water meter on your house to generate your bill, they want to make sure that they have accurately accounted for the water usage, so they do not charge you too much or too little. The cost of industrial water flow meters can vary greatly in price, depending entirely on the demands of the application.

What Flow Meters Can Handle Hot Water?

The flow meters that can handle hot water are the ones whose materials and any integral electronics tolerate high temperatures. Most hot water flow meters will be made of metal, as various plastics are not suitable for high temperatures. Some common hot water flow meter technology types are Variable Area (Rotameters), Differential Pressure, and Vortex.

Some hot water flow meter models will place any sensitive electronics away from the flow body to help isolate them from the high operating temperatures. Certain flow meter technology types do not lend themselves well to hot water measurement, as the principles of operation limit the maximum temperature capacities.

Chilled Water Flow Meters

Chilled water flow meters are marked by an ability to handle lower media temperatures. Different flow meter technologies and different individual flow meter models offer different minimum temperature capacities. When choosing a chilled water flow meter, make sure to verify that the meter is equipped to handle the very lowest potential media temperature that the process may produce.

Can Water Flow Meters Measure Wastewater and Sewage?

Not all of them. Industrial processes can produce what is known as "wastewater", which can be comprised of any number of elements in addition to water, and many typical water flow meters are not suitable to be used as wastewater or sewage flow meters. To monitor or measure the flow of this after-the-process water, wastewater flow meters are needed.

Wastewater is also a term commonly used for sewage.

What Flow Meters Can Be Used for Water Cooling Applications?

Flow meters for cooling water are used in a wide variety of water-cooling circuits in many different industries and applications. They are commonly used to ensure that the water is flowing at a rate that enables the cooling system to maintain proper process temperatures. If the water is not flowing sufficiently and the process area is not cooled enough, the product could suffer quality issues.

One example of a cooling application is MRI machines, where water cooling is used to keep the coils cool. This application requires a water-cooling flow meter with good accuracy, high turndown, and the reliability of no moving parts, like our DUK Ultrasonic Flow Meters.

Steel mills also use a lot of cooling processes, like cooling for castings. Induction furnaces that create the heat to process the metal generate high magnetic fields that would affect certain types of flow meter technologies, like magnetic flow meters. Metal processing applications also require a heavy-duty build that can withstand the rigorous process conditions.

What Water Flow Meters Should Be Used with Pumps?

Water flow meters for pumps are used to verify that the pumps are doing their jobs correctly. They are typically inline flow meters. They need to provide an accurate representation of the flow rate being produced by the pumps, so higher accuracy is normally a necessity for water flow meters for pumps. If the pump and process is creating a lot of pressure, then higher pressure capabilities would be required from the flow meter. Flow meters can also be used to protect pumps, as pumps should not operate without the media flowing through them. Flow meters can verify that sufficient flow is occurring to eliminate pump burnout from them running dry.

What Units of Measurement Do Water Flow Meters Use?

Most flow meters offered in the US will be available in units of gallons per minute, or GPM. The exception to this would be flow meters that measure flow by other units, like feet per second or pounds per hour. KOBOLD offers an extensive line of flow meters that provide flow rate readings in gallons per minute or gallons per hour.

Can Water Flow Meters Have Digital Displays?

Yes. Water flow meters with digital displays come in a wide variety of options, and choosing one version over another depends on the functionality the flow meter needs to provide and the cost. Simple displays that cost less may be more than enough to show an ongoing rate of flow, while more complex displays can show totalizing or batching.

Some can show different variables simultaneously on the display, and others can be programmed to show different variables depending on the process requirements. Display screens can vary in visibility, so make sure the option you choose will be readable at the place of installation if it is being read in-place. Another consideration is the power source for a digital water flow meter. Some are battery powered and others are externally powered.

Sample digital water flow meters from KOBOLD include the following models.

What Are Inline Water Flow Meters?

Inline flow meters are flow meters that have an integral "flow body" that is installed in between two sections of pipe via connections on the inlet and outlet side of the flow meter. The measuring tube in the flow body becomes part of the piping. There are many types of inline water flow meters. Most any flow meter technology is available in inline installation models. There are many different types of process connections to secure the meter into the piping system. Common connection types in the US are male or female NPT thread, ANSI flanges, Tri-Clamp, socket connections, hose connections, and weldable connections.

The advantages to inline flow meters are that they are available in technology types that do not have any protuberances within the flow stream. That reduces the possibility of wear and tear or damage. Certain inline models can also offer less straight run requirements than insertion models, depending on the exact flow meter technology type. Inline meters can generally provide a more accurate reading than a similar insertion counterpart.

Sample inline water flow meters from KOBOLD, by connection type, include the following models.

What Are Insertion Water Flow Meters?

Insertion water flow meters are installed in a method that is different from inline flow meters. Insertion meters can be introduced into an existing system with much less system disruption, as they do not require pipes to be disassembled as inline flow meters do. Instead, a hole is introduced to the current pipe and the probe is fitted into the flow stream. Any electronic display elements are kept outside of the pipe and are either affixed to a surface or are held up by the long rigid probe body.

Insertion water flow meters also offer the advantage of easier removal for periodic cleaning or calibrating. Some models, like our PIT Insertion Magnetic Flow Meter, can be supplied with a supplemental extraction device that does not require system shutdown while the meter is being removed. Insertion water flow meters are also a good choice when the installation area is cramped or difficult to get to. It only requires access to the desired entrance point for the probe.

Do Water Flow Meters Come In Clamp-on Versions?

Yes. Clamp-on flow meters are almost exclusively ultrasonic technology, due to the inherent measurement principle that does not require media contact like other flow meter technologies. They are referred to in many ways, including strap-on flow meters and portable flow meters. Clamp-on installations can be temporary or more permanent in nature, depending on the method used to affix the transducers to the pipe.

Ultrasonic technology requires that the pipe have sufficient conductivity to carry the acoustic signals. Because clamp-on installations do not intrude into the pipe, it is ideal for water applications where the water is contaminated or has large particulate matter that may damage other flow meter installation types with sensitive measuring elements.

Ultrasonic Water Flow Meters

Ultrasonic water flow meters are available in both clamp-on versions, like the DUC Clamp-on Ultrasonic Flow Meter, or inline versions, like our DUK Inline Ultrasonic Flow Meter. They offer the distinct advantage of no moving parts, which allows for a long service life with very low maintenance. To learn more about ultrasonic water flow meter technology, visit our ultrasonic flow meter technology page.

Water Flow Meters with Alarms

Flow meters with alarms monitor whether there is too much or too little flow in a system. They are used to identify flow rates that fall below the required process rates and can be used to prevent pump burnout from a pump operating dry. They are sometimes used to verify that the flow rate is not too high. Flow meters with integral switches can shut down a process if the falling flow rate would cause harm to the system.

Flow Meters with Totalizers for Water

There are many flow meters for water that offer digital totalizing capabilities. Many flow meters with totalizers offer both resettable and grand totalizing elements inherently within the electronics. KOBOLD offers a wide variety of water flow meters with integral totalizers. Here are our top water flow meter models with totalizers.

Flow Meters for Water Tanks

Flow meters for water tanks are usually inline flow meters used to monitor how much water is going into the tank or coming out of the tank. Although knowing the flow rate is helpful, the primary function of a water flow meter for water tanks is usually batching or totalizing. Batching capabilities allow a process to dispense a precise amount of media into a tank before the flow is stopped. This is important when creating mixtures with water. Totalizing provides the total amount (not the rate) dispensed in a certain time frame. Some flow meters for water tanks can provide rate, batching, and totalizing capabilities, like our MIM Magnetic Flow Meter.

High Flow Water Meters

High flow water meters are generally made of durable materials that can withstand the rigors of the forces involved, and the technologies that provide a long service at high flow rates are the ones with no moving parts: magnetic flow meters, ultrasonic flow meters, vortex flow meters, Coriolis flow meters, and differential pressure flow meters.

Flow meters come in a wide variety of flow rate capacities. Certain flow meter technology types are better suited to providing a long service for high flow rates. For example, a paddle wheel flow meter that uses a physical mechanism to measure the flow will not last very long under strenuous use. With no moving parts, there are no elements that are subject to wear and tear at higher flow rates. These technologies are a good place to start in determining which type of flow meter will handle your high flow rate well.

How Do I Use a Water Flow Meter?

Using a water flow meter comes down to installing it and reading it. Most water flow meters are going to be inline installations, inserted into the pipeline via integral connections on each side, the inlet and the outlet, of the flow meter. How you read the rate will be determined by the technology type of your water flow meter.

Water flow meters come in all sorts of shapes, sizes, technologies, and have a variety of different features. Insertion water flow meters require a hole to be made in the pipe and a connection to be added to the pipe that can screw into the process connection on the flow meter. Clamp-on flow meters are simply affixed to the outside of the pipe with a permanent or removable strap or chain.

For instance, variable area flow meters are typically read on the top of the float that sits inside a glass or plastic tube. Other flow meters will offer a mechanical scale where the arrow moves up or pivots to show the rate of flow. Other types offer an output that can power digital displays. Visit our article to learn more about how to read a flow meter.

Water Flow Meter Manufacturers

There are a wide variety of instrumentation companies that manufacture water flow meters, as water is an extremely common media. If you have a need for an industrial water flow meter, it is important to choose and work with a company with an abundance of experience to make sure that the right flow meter is selected for your needs, to reduce lost revenue and eliminate headaches down the road.

Unlike many other manufacturers, we design, manufacture, sell, and support our water flow meters, and are well positioned to be your partner for your application. We are also well known for providing custom solutions to applications that other manufacturers cannot provide solutions for. Many of our current products were created out of specific customer application needs and feedback.

Learn more about why you should partner with KOBOLD for your application.

Not sure which water flow meter fits your application? Schedule a free engineering consultation and our engineers will show you the exact flow meter that best fits your application parameters and your budget.

Frequently Asked Questions

Last Updated: October 20, 2026