Water Level Sensor: Applications, Operation, Types and Technology

Water Level Sensors

Table of Contents
Water level sensor, flood water level monitoring

What is a Water Level Sensor?

A water level sensor is an instrument that monitors the level of water in tanks, containers and reservoirs. These devices use different technologies to measure level accurately, making them useful for various applications.

Water Level Applications

Water level sensors find applications in municipal water and wastewater treatment plants, industrial process plants, agricultural irrigation systems, marine operations and many other industries. These level measurement sensors help with process control, automation, efficient resource management and enhancing safety. Let’s have a look at a few examples for these industries:

Municipal Water and Wastewater

Why measure water levels in municipal water treatment plants and sewage systems?

Measuring water levels for municipal water and wastewater treatment applications is important for effective treatment and management. This information allows operators to monitor water usage, detect leaks, and regulate flow rates throughout various processes.

Integrating water level sensors with control systems automates filling, draining, and pumping processes, enhancing operational efficiency and reducing manual intervention. These sensors also ensure precise control over water levels, preventing overflow or underflow, thereby maintaining treatment effectiveness, infrastructure integrity and safety.

water level sensor, wastewater level sensor

Industrial Processes

Why measure water level in industrial tanks, boilers, and processes?
oil-water interface detector, oil-water interface

Measuring water levels in industrial tanks, boilers, and processes is important for operational efficiency, safety, and quality control in the chemical, plastics, food and beverage, and pharmaceutical industries. Real-time monitoring provided by water level sensors prevents overflows in tanks, mitigating damage and wastage. 

Integration of these sensors with control systems enables process automation, enhancing operational efficiency and reducing manual intervention. As a result, water level sensors can contribute to significant cost savings for manufacturers.


Why measure water level in reservoirs, oceans, rivers, lakes and ponds?

Measuring water levels in reservoirs, oceans, rivers, lakes, and ponds is critical for environmental applications. This information aids in assessing water availability, managing resources, and forecasting floods or droughts. Additionally, monitoring water levels supports environmental observation, navigation safety, and hydrological research. 

Water level sensors play a crucial role in safety by alerting to potential floods or low water levels, enabling timely intervention and risk mitigation. They also offer valuable data for analysis and trend identification. 

flood sensor, flood level detector, flood monitoring


Why measure water levels in irrigation systems, reservoirs, and agricultural fields?
irrigation flume flow rate

Measuring water levels in irrigation systems, reservoirs, and agricultural fields is essential for efficient water management in farming and agricultural applications. It ensures accurate irrigation scheduling, prevents water wastage, and conserves resources. 

Additionally, monitoring water levels aids in optimizing crop yields and mitigating water-related risks, thereby enhancing agricultural productivity and profitability.


Why measure water level in ships, boats and maritime structures?

Measuring the water level in ships, boats, and maritime structures ensures safety, stability, and efficiency for marine applications. It prevents overloading and maintains buoyancy and maneuverability. 

Monitoring water levels also helps avoid collisions with underwater obstacles, controls ballasts, and alerts of potential flooding risks. Furthermore, real-time monitoring provided by water level sensors prevents overflows in tanks and reservoirs, averting damage while enhancing safety. 

In addition, radar altimeters are integral to marine navigation. They offer precise depth measurements that enhance safety and efficiency, particularly in challenging or unfamiliar environments.

ABM’s fast response radar sensors ( 15-20 echoes per second) are used in speed boats to monitor the distance between the boat and the water surface.

Hydroelectric Power Generation

Why measure water level in hydroelectric power generation dams and reservoirs?

Monitoring water levels in dams and reservoirs is critical for regulating water release for power generation. This information is essential for optimizing power output and ensuring safety. By managing water flow, consistent energy production is maintained while mitigating the risk of downstream floods or droughts. 

Moreover, monitoring aids in evaluating environmental impacts, efficiently managing water resources, and safeguarding against structural risks and emergencies. Integration of water level sensors with control systems automates processes, enhancing efficiency and reducing manual intervention.

How Does a Water Level Sensor Work?

A water level sensor works using different methods depending on the technology. Generally, the sensors can be categorized into two groups: continuous level or point level.

Continuous Level Measurement

Continuous level sensors provide real-time monitoring of water levels, making them ideal for precise measurement in many applications. Technologies such as ultrasonic, radar, and capacitance sensors fall into this category and offer accurate and reliable data output for process control and automation.

Point Level Measurement

Point level switches indicate when the water level reaches a predefined threshold, serving as alarms to prevent overfilling or depletion. Examples include float switches, probes and non-invasive switches. These devices offer simplicity and reliability for basic level detection.

types of level measurement, level measurement

Types of Water Level Sensors

Water level sensors come in different types, including contact and non-contact sensors: 


A contact level sensor is a device used to measure the level of water by making physical contact.  It typically employs probes or floats that detect when the liquid reaches a certain level or monitors the level continuously.


A non-contact level sensor measures the level of water without physical contact. It employs ultrasonic, radar or laser technologies to detect the distance between the sensor and the water surface. This type of sensor is often used in industries where contact with the liquid is impractical, undesirable or maintenance intensive.

Water Level Sensor Technologies

Several types of water level sensor technologies, including radar, ultrasonic, pressure or capacitance, are used to determine water levels accurately. Each sensor type has advantages and limitations, and the choice depends on factors such as the application requirements, environmental conditions, and accuracy needed.

At ABM, our water level sensors use ultrasonic and radar level technologies to monitor liquid level. Below is a brief overview of these sensor technologies to aid as a resource while you are evaluating technologies for your application.

Non-Contact Radar Level Sensors

A radar level sensor emits microwave signals towards the water surface and measures the time it takes for the signals to return, determining the water level. The sensor is ideal for applications requiring precise and continuous level measurement in challenging environments, including wastewater tanks and hazardous areas, as well as applications with harsh conditions, such as extreme temperatures, vapours, or foam.

Non-Contact Ultrasonic Level Sensors

An ultrasonic level sensor emits ultrasonic pulses into air and measures the time it takes for the pulses to bounce back from the water surface, calculating the distance and, thus, the water level. The sensor is ideal for applications requiring accurate and reliable level measurement without physical contact, such as reservoirs, rivers, and tanks without vapours, gases or surface foam.

Submersible Ultrasonic Level Sensor

A submersible ultrasonic level sensor measures water level by emitting ultrasonic pulses into the liquid and calculating the time it takes for the pulses to return. The sensor is particularly well-suited for continuously monitoring the water level above a submersible pump for control or interface detection of sand or sludge in water.

Non-Invasive Ultrasonic Level Switch

A non-invasive ultrasonic level switch detects water levels without direct contact by emitting ultrasonic waves from outside the container and detecting the presence or absence of water directly opposite the switch. The switch is ideal for applications requiring simple, reliable point-level detection without physical contact, such as tank alarms.

Advancements in Technology

Advancements in technology continue to move water level sensors into the future, with various options available for users to find a sensor that best meets their needs. In addition, wireless connectivity and IoT have enabled remote monitoring and real-time data collection, that provides user more convenient data access and allows quicker responses to changing conditions.

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