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How to Clean RV Holding Tank Sensors? Quick and Easy Guide

Written by Philip Lopez / Fact checked by Paul Lemaire

how to clean rv holding tank sensors

Many RVs are equipped with tanks such as gray tanks and black tanks to contain wastewater from the shower, toilets, or sewage in your kitchen. To know the appropriate time for removing these sewages from the tanks, the RVs are integrated with the holding tank sensors to signal to users. This design is extremely convenient in showing different levels of water, measuring 1/3, ⅔, or full for your regular check-up.

However, in some cases, the sensors can misread the level because of building up debris from sewage. They cover the metal nubs of sensors and give us wrong information. That is the reason why we should clean not only the tanks but also the sensors.

In this article, I’m glad to share pieces of information on how to clean RV holding tank sensors that I have succeeded.

Table of Contents

What Causes RV Holding Tank Sensors to Misread?

The most popular problem why the sensors misread is they have been used for a long time so they can be broken. Additionally, the sensors can be covered by something like food, toilet paper, etc. Your RV can have this problem in both the black tank and the gray tank. Additionally, you should know exactly the reason and debris of each tank to have different solutions.

Gray Tanks

The gray water holding tanks consist of grease, fats, food waste, oils, soap, and shampoo. These things can create thick slime to cover the metal nubs of the sensor. So you can see the full level light will be on even though a tank is empty.

Black Tanks

The main reasons cause the misreading of the sensor in the black tank are toilet paper and human feces. When the waste is diluted into the water inside the black tank, it can make residue that latches on the sensor. Besides that, if you don’t use suitable toilet paper or too much it, the tank sensor can cause a misreading problem is not inevitable.

How to Clean Your Holding Tank Sensors?


Gray Tanks

Before cleaning something, we should care about clean solutions to remove the entire residue and maintain good conditions for our product. With the gray tank of your RV, we have the best clean solutions is Geo method:

  • ½ cup water softener (Calgon is the most common)
  • ½ cup laundry detergent

Steps to clean the sensor of gray tanks

Step 1: Close the valve of your gray tank.

Step 2: Fill your gray tank with water (You can fill the water at the highest level of the sensor to remove entire debris.

Step 3: Glug 20 or more ounces of dish soap down the kitchen sink line. You can see it foaming back out of the shower lines or the sink and it is okay. The enzymes of grease-eating will run through the pipes to remove grease.

Step 4: Keep this work overnight during your sleep.

Step 5: In the next day, open the valve of a gray tank and dump it.

Step 6: Fill and dump your tank a few times to rinse it completely. You can repeat this process until the sensor is restored.

Black Tank

To clean the holding tank sensor of the black tank, we can use one of these options about cleaning solution are:

  • Sensor cleaner
  • Bleach

Steps to clean the sensor of black tanks

Step 1: Close the valve of your black tank.

Step 2: Fill your black tank with water (You can fill the water at the highest level of the sensor to remove the entire debris).

Step 3: Shake the bottle of your sensor cleaner very well.

Step 4: Use one half of the bottle sensor cleaner and pour it into the black tank through your toilet.

Step 5: Keep it as long as you can. You can keep this solution in the black tank from 48 to 72 hours for optimal clearing. When you put the sensor cleaner to your work longer, you allow active microbes to have more time to digest the residue on the metal nubs of the sensor.

Step 6: Open the valve of the black tank and dump the water.

Step 7: Rinse your tank thoroughly and you can repeat this process if necessary.

A Lot of Helpful Things You Should Remember


  • Do dump your gray tank after dumping your black tank.
  • Do close your gray tank valve to preserve water before dumping your black tank.
  • Do scrape dishes to remove food and grease before washing.
  • Do not use bleach to wash the gray tank.
  • Do not allow hair down or food the drains – use a strainer.
  • Do not dump illegally.


I hope the pieces of information in this article can help you clean your holding tank sensors. Remember that you should dump your tanks frequently and legally to prevent unexpected problems.

Did you find pieces of information beneficial with your RV sensors?

Let us know in the comments below!

Please share them with other campers once you are successful.

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