Marine Water Tank Level Sensors: Get Your Boat Tank Level Right

Are you constantly worried about running out of marine vessel fresh water, even after you’ve just filled it up? Are you tired of the endless unplanned trips to the marina dump stations? Don’t worry, there’s a perfect solution for you - Marine Water Tank Level Sensors!

With the help of these liquid level indicators for marine tanks, you’ll never have to worry about your vessel’s tank levels again. Keep reading to learn more about how these marine liquid tank level indicators can help you get your boat tank levels right every time!

What are Marine Water Tank Level Sensors?

Marine water tank level sensors are specially designed sensors used to measure the level of liquid in a marine tank. Marine tank level sensors can be used in both fresh and drinkable water and gray or wastewater tanks, and they can detect levels from very low to very high.

These devices can use technologies such as absolute pressure, capacitance charge, or electromagnetic wave measurements to convert the liquid level into an electrical signal which is then sent to a control panel. The control panel of a marine water level sensor provides digital readouts of each measuring point in a continuous manner. The control panel facilitates the monitoring, logging, and controlling of the liquid level in the tank.

The sensors are often used in conjunction with an alarm system to alert the user when the level of liquid in the tank reaches a certain level.

Why Install a Marine Tank Level Sensor in a Boat?

Having a marine tank level sensor is incredibly beneficial because it can continually monitor the level of fresh and wastewater in a boat’s liquid tanks. This is so important because it helps prevent overflow and can even help detect leaks.

For example, if you have a large boat with a lot of liquid tanks, you can be sure that the levels are always safe and maintained with a tank level sensor. This can also help you save money by not having to constantly manually check the levels, which can be both time-consuming and costly.

Types of Marine Tank Level Sensors and How They Work?

Marine tank level sensors fall under 3 categories– floating, external, and submerged. Here are examples for each of these categories and their working principles.

1.     External tank level indicators

External tank level indicators are devices that measure the amount of liquid in a tank from outside the tank. Common examples here are capacitance charge probes and float sensors.

  • Capacitance charge probes

Capacitance charge sensors utilize a probe that is lowered into the tank and submerged in the liquid. The capacitance changes as different amounts of liquid and air are exposed to the length of the probe, which allows it to detect this variation.

  • Float sensors

Float sensors employ floats that move up and down a tube filled with liquid, which is connected to the bottom of the tank. As the water level in the tank rises and falls, the floats travel up and down the tube accordingly, allowing the sensor to detect the water level.

2.     Submerged marine water tank level sensors

Submerged marine water tank level sensors measure the water level from inside the tank, providing an accurate and reliable indication of how full or empty the tank is. A good example in this category is a pressure sensor.

  • Pressure sensor

Pressure water level sensors work by measuring the absolute hydrostatic pressure generated by gravity acting on the liquid. The pressure sensor is installed in a hole in the bottom of the tank. The absolute pressure is then used to accurately calculate the liquid level in the tank.

3.     Non-contact marine water level sensors

Non-contact marine water level sensors are electronic instruments that measure and monitor water levels without having to come into direct contact with the water. Ultrasonic sensors are the most common type of non-contact marine water level sensors.

  • Ultrasonic sensors

Ultrasonic marine water level sensors are devices that measure the distance from the surface of the liquid to the sensor by sending out sound waves and measuring the time it takes for the waves to return.

Choosing the Best Sensor to Determine the Level of Fluid in a Marine Tank

Here are the top factors to consider when choosing a boat water tank level sensor and recommendations for each:

Tank Shape

The shape of the tank will determine what type of sensor can be used. For example, a narrow long tank with limited internal space would be best suited for an ultrasonic sensor, which requires no contact with the media.

Measurement Range

When choosing a sensor for a marine tank, it is important to consider the measurement range. A wide range that accommodates the depth of the tank in question is ideal.

Output Type

Depending on your needs, you may want to select a sensor with an analog or digital output. An analog output allows for more precision, while a digital output is easier to read and interpret.

Power Options

The typical power source for a sensor in a marine tank is 12-volt DC, but other power options may be available depending on the power source you use on your boat.

Tank Accessibility Needs

For external tank level indicators, it is important to select a sensor that is easily accessible. This will make it easier to install, maintain and repair the sensor. External tank level indicators may require more accessibility than other types of sensors.

Make Material

It is best to choose a sensor that is made of an anti-rust material, such as stainless steel, as this will ensure that the sensor can withstand the harsh conditions of marine environments.


When selecting a sensor for a marine tank, it is important to choose a reliable brand. Popular brands for marine sensors include Faria, VDO, Raymarine, Simrad, and Garmin. These brands are known for their high-quality products and reliable performance.

How Do You Install a Marine Water Tank Sensor?

The process of installing a marine water tank sensor depends on the kind of sensor you have. Here are some general steps to help get you started:


  1. Make sure the area you’ll be working in is easily accessible and that you have the right tools and supplies.
  1. Read the manufacturer’s instructions carefully and ensure you follow all safety recommendations.
  1. Install the mounting bracket and secure it to either the exterior wall or the interior of the tank.
  1. Attach the sensor to the mounting bracket using the right screws and fasteners.
  1. Connect the wiring to the sensor, the control unit, and the power supply.
  1. Test the sensor to make sure it’s working properly.
  1. Monitor the readings regularly to ensure accuracy.


Depending on the type of sensor, you may need to follow additional instructions for installation. Consult the manufacturer for more specific instructions when installing your sensor.


What is the difference between a level switch and a level sensor?

A level switch is typically used to detect the presence of a high or low level, and it will be triggered when the level reaches a certain point. A level sensor, on the other hand, continuously measures and relays the exact level of fluid being monitored, providing more precise and detailed information.

How often should I check the level of my marine water tank?

The frequency of checking the level of your marine water tank will depend on the type of sensor you are using and the type of water in the tank. Generally, it is recommended to check the level at least once a month or as needed based on usage.

How do I maintain my marine water tank level sensor?

To ensure the accuracy and reliability of your marine water tank level sensor, it’s important to regularly inspect it for corrosion, wear, and any other damage. Depending on the type of sensor you are using, it may also require periodic cleaning or calibration.


So there you have it! Now that you know all about marine water tank level sensors, you can finally get your boat tank level just right. No more guessing or relying on faulty monitoring systems - you can trust in the accuracy and reliability of a quality tank level sensor. So, don't be left high and dry - get your tank level right and enjoy a smooth sailing experience with your marine vessel.



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