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How to Unclog an RV Toilet Holding Tank without Making a Mess?

Writen by Tom Hank

Fact checked by Joseph Varney

how to unclog an rv toilet holding tank

There are many reasons that your RV’s toilet is not working properly. One of the relatively more common reasons is that the toilet has a blockage in the holding tank. So now the question is, how to unclog an RV toilet holding tank?

As an RV owner, you can use a conventional plunger for this task, though it is not the most efficient solution in unclogging RV toilet. Instead, you can use an RV holding tank cleaning solution.

However, you need to use this solution correctly. Otherwise, you are going to run into some issues, and, in some cases, make things worse than before. So keep reading to know the correct steps to fix a clogged RV toilet.

Table of Contents

What You’ll Need


Like any RV DIY project, it is best to gather a few things if your RV toilet won’t drain. To clear a clogged RV toilet, you need the following items:

Protective gear: In most cases, you only need to wear disposable gloves for fixing an RV toilet clogged. But you may also use additional personal protective equipment to enhance safety during the task.

For instance, if you are about to deal with a significant mess (because the blockage returned some of the human waste to the RV’s bathroom), you may need to wear rubber boots.

Also, consider wearing eye and face protection. The fumes generated by liquid waste can be toxic if you are breathing large quantities of them over extended periods.

RV holding tank cleaning solution: These solutions tend to come in two forms: tablet and liquid.

The tablet holding tank cleaner will form small particles when dipped into the toilet water. These miniature substances will go through the plumbing and into the septic tank, removing RV clogs along the way.

On the other hand, an RV holding tank liquid treatment requires you to pour it into the toilet’s container. Like its tablet counterpart, it will create substances that will go to the septic tank and eliminate toilet clogs.

Liquid solutions tend to be more potent than tablet cleaners. However, it is more convenient to use a tablet holding tank cleaning solution than its liquid form.

Also, make sure to use a product that is septic safe. Using a septic safe treatment solution can help prevent future clogs.

Step-by-Step Instructions

At first, unclogging an RV toilet holding tank seems like a massive undertaking. But upon closer inspection, the process is relatively straightforward.

Here are the steps to remove clogs and blocks from the holding tank of your RV toilet:

Step 1: Close the Black Water Tankboiling-water-to-unclog-rv-toilets

Black tanks collect the wastewater from RV toilets in campers, motorhomes, travel trailers, and other types of RVs. Additionally, RV black water tanks are only for the collection and holding of sewage wastewater.

Leaving the black tank valve open can cause clogs that you’ll eventually have to deal with. This happens because there won’t be enough water to move solid waste out from the tank, resulting in a blockage.

Therefore, locate your RV black tank valve and close it. In turn, black tank cleaners will sit with the clogged materials to dissolve them properly.

Step 2: Add Water to the Tank


Check the clogged black water tank to see if there is enough water in the container. If there isn’t, add more water to it. However, if there is already a sufficient amount of water in the tank, skip this step. Make sure that the tank does not overflow if you add extra water into it.

Step 3: Pour the RV Toilet Holding Tank Solution

This next step depends on your type of toilet holding tank cleaner. If you have the tablet model, you only need to chuck the recommended number of tablets into the holding tank and wait for a few hours.

On the other hand, if you have the liquid version of the holding tank solution, make sure to use the entire bottle.

Then, wait for about 12 to 27 hours to let the solution sit in your toilet’s holding tank. Do not use your camper toilet during this time, which means that you should do your bathroom ‘business’ before you start this project.

The treatment will dissolve toilet paper in RV holding tanks, along with other substances that block the plumbing. But you may need to wait for a few hours or more than a day for the solution to remove the RV toilet paper and other clogs efficiently.

Step 4: Empty the RV’s Black Tank


After waiting for 12 to 27 hours, open the black water tank in the RV again. This time, do a black tank flush (and even a gray water tank cleaning while you are at it) as the RV toilet system may still have solid waste or residue from dissolving the toilet clogs.

Make sure to run one or two more emptying cycles on the black water tank if it does not empty the first time. You will know it has not yet cleaned enough wastewater if a foul tank smell exists.

Then, clean the RV black water container with your preferred tank-cleaning solution. It should take about 20 minutes for the holding tank cleaner to remove all the unwanted debris from the tank. Otherwise, you may have to wait a little longer than usual.

Close the black tank again after the cleaning operations. This is for preventing rv toilet clogs from forming onto the toilet pipe.

Other RV Toilet Holding Tank Unclogging Methods to Try


Many RV owners prefer using a holding tank cleaning solution to remove clogs from their toilets. However, in some cases, it can be challenging for rig owners to get a hold of the treatment, especially when they are outdoors and it is camping season.

For example, you might be camping in the boondocks. Furthermore, the nearest hardware store is miles away, which might not be part of your RV travel destinations or current camping trip.

If you find yourself in a similar situation, here are some alternate solutions to unclog your RV toilet.

Use a Plunger

As previously mentioned, an RV toilet plunger might not be the best solution for removing some types of blocks in toilets. It is because the in-and-out motion generated by the plunger can make the clogs worse instead of better.

Still, a plunger can be a viable solution if you are dealing with a relatively minor obstruction. This tool can also be your first choice to try and remove the clog as it tends to be readily available in many RVs.

Use Boiling Water

You can also use ordinary boiling water to unclog RV toilet. Again, you should take note that this might not work for RV toilet clogs.

With that said, using boiling water tends to promote fewer risks than using a plunger. Furthermore, you only need to heat water on your camper or motorhome’s stove or use a dedicated water heater.

Then, pour the boiling water directly into the holding tank. But make sure that your toilet’s parts are sufficiently durable to handle the hot temperature. Otherwise, you might see some dents or warps forming, which can occur on cheap plastic parts.

Next, wait for about an hour for the boiling water to try and dissolve the clog. The boiling water can also be your glorified tissue digester if that is the cause of the clogged toilet. If it fails the first time, try pouring another batch of boiling water into the tank.

Use a Plumber’s Snake

A plumber’s snake is a flexible, slender, and often worn auger used to remove clogs in the sewer line. Generally, you can use this tool to avoid damaging a pipe or a toilet during cleaning or unclogging operations.

Many RV owners, and even household owners, do not prefer using a plumber’s snake to remove a clog from the toilet holding tank. It is because this tool can leave a mess and a nasty smell, even though it can be quite effective in removing a clog in the plumbing.

Therefore, if you are going to use a toilet snake for this task, make sure that you are also using additional personal protective gear. Also, it is ideal to use a plumber’s auger with a powerful rotary cleaning action. Additionally, have another person with you for help.

Now that you have your protective gear worn, one person should place a bucket under the sewer opening of the black valve. Then, close the black water tank and drain any stubborn waste that may still be lingering in the container.

The person holding the probe cleaner should insert the tool into the holding tank after the black water tank drains. Then, move the tool up and down (or use the crank, depending on your type of plumber’s snake).

Once water seems to flow properly again in the holding tank, the person near the black water tank can now close the sewer valve.

Use the Ice Cube Method

Dropping ice cubes into the RV toilet’s holding tank may also work. It works similarly to boiling water and pouring it into the toilet’s container. It also means that this method may or may not work in some scenarios.

With that said, fill your toilet’s holding tank with as many ice cubes as you can. But make sure to get water in your toilet up to about 1/3rd of the container’s total volume. Then, attempt to flush the toilet, and continue doing so to drive the ice cubes into the plumbing.

If this method works, the ice cubes should dissolve the RV toilet clogs. You will know if it worked if an ice cube will start flowing into the bathroom’s plumbing with seemingly no hassle. It will then follow with the rest of the ice cubes in the RV’s toilet holding tank.


Did you like this guide on how to unclog an RV toilet holding tank? Share your feedback and thoughts in the comments. Also, consider sharing this article with others to help them unclog their toilets’ holding containers.

Remember, you may choose to use an RV holding tank cleaning solution for this task. But if you cannot get a hold of that product, you can use alternatives like a standard plunger, boiling water, and even ice.

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