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How to Unclog an RV Toilet Holding Tank: 4 Methods

Written by Philip Lopez / Fact checked by Paul Lemaire

how to unclog an rv toilet holding tank

When your RV toilet won’t drain, you’ll be stuck wondering how to unclog an RV toilet holding tank. Your trip will also become unpleasant as a result. Luckily, I have found a few methods that are effective in solving this problem.

One of the easiest ways to unclog an RV toilet is to pour boiling water into it. You can also use drain snakes and chemicals to remove the clogs. The key here is to perform these methods correctly.

To solve this messy problem, here are some effective methods to unclog an RV toilet holding tank.

Table of Contents

But First, Make Sure That You Have a Clog

The first thing that you’ll want to do is to ensure that your toilet has a clog. It’s easy to tell if you have a clear hose. When you see a small trickle of liquid draining from your tank, then it’s confirmed that you have a clog problem.

Make use of your ears when your hose isn’t clear. If you hear a small amount of liquid dripping when you dump, then it’s likely that your toilet is clogged.

What You’ll Need


Once you’ve confirmed that you have a clog in your RV toilet holding tank, it’s time to gather the supplies listed below.

Gloves And Other Protective Gear

This task can get messy, so you’ll need a good pair of gloves to protect your hands from any splattering waste or debris. Since you might be dealing with waste, I recommend a pair of disposable rubber gloves.

You can also wear a pair of rubber boots to protect your feet from any significant mess that might splatter on the floor. Also, consider using some eye gear or face shield. The liquid waste might discharge some toxic fumes, which can be disastrous for your health.

For Method 1

  • Water Hose

The water hose will provide the water pressure that you’ll need to try to wash away the cause of the clog. Never use the same water hose that you’ll use in watering the plants or refilling the water tank. Instead, use an old water hose that you won’t use again or buy another long hose and connect it to a faucet outside.

If the water pressure is too low, you might need to connect the water hose to a compressor.

For Method 2

  • Boiling Water

You’ll need hot water to help loosen any clogs in your toilet. In some cases, it can even help dissolve toilet paper in RV.

Prepare at least a gallon as long as it fits inside your toilet holding tank. Any type of water will do. You can use the stove to heat the water in a pan or pot.

For Method 3

  • Toilet Plunger

The most common tool to use for RV toilet clogged issues is a plunger. The push-and-pull motion of using this item will work best on minor clogs.

The beauty of a plunger is that it’s readily available. You can find this in many RVs, so you can grab this to apply an immediate solution to the clogging problem. Find one that’s long and durable enough to really work up anything in the pipes.

  • Drain Snakes

Drain snakes are great in removing stubborn clogs that an RV toilet plunger won’t eliminate in the toilet holding tank. Compared to RVs with straight pipes, those with angled pipes are more susceptible to clogging. For this more difficult case, you’ll need a drain snake to remove any clogged debris from the toilet to the holding tank.

I use the Omont 4-Pack Drain Snake, which can remove anything from hair to small items.

  • Bucket

A bucket comes in handy to catch any escaping liquid when you try to work the drain snake into the dump pipe and tank. More specifically, a spurt of black water might get out, which can be a little messy.

Any type of bucket will do – plastic or metal. The size of the bucket should be more than the capacity of your holding tank. Choosing something smaller might lead to an overflow of black water liquid on the floor.

For Method 4

  • RV Tank Cleaning Solution

You can buy a drain unclogger to get rid of the clogs. Choose one that’s compatible with your RV tank, as other products may not work well. Avoid using harsh chemicals, like bleach, as they cause damage to your RV’s plastic pipes.

RV holding tank solutions may come in two forms – tablet and liquid. My favorite product is the Unique Tank Cleaner Liquid, but any RV tank treatment should help solve your clog problems.

You can also substitute this solution with one cup of dishwashing liquid, one cup of water softener, and boiling water.

Step-By-Step Instructions


Once you have gathered the necessary supplies, you can start doing the dirty work. This task might look difficult, but it’s easy if you know the correct process.

Wear Gloves And Other Protective Gear

Before you start this method or any other methods in this list, wear gloves. You can also wear some rubber boots, a face shield, or an eye shield. Working with clogged toilets means dealing with waste, so you need to be duly protected.

I like to use disposable gear as they’re pretty convenient.

Method 1: Water Hose

  • Power Wash

Connect one end of your hose to a water source. Position the hose down the toilet and set the water pressure from moderate to high. You can connect the water hose with a compressor to elevate the pressure.

Spray the water where the clog is located. In some instances, the high water pressure will disintegrate any buildup and transfer them into the sewer hose.

Method 2: Hot Water

Using boiling water to unclog RV toilet is also a quick and easy way to solve this problem. However, this needs a bit of patience and a cover of your nose from some really stinky odor.

  • Step 1: Boil Water

First, make pots of boiling water on your stove or water heater. Use a large pot, so you don’t need to do multiple batches. For extra convenience, use a thermos or water heater to make hot water.

Set the boiling water aside for a couple of minutes. You don’t want to pour boiling water straight into the toilet because it may cause serious damage to the PVC piping and seals.

  • Step 2: Turn Off The Water Main

While waiting for the boiling water to cool down a bit, open the toilet valve.

  • Step 3: Pour Hot Water

Now, pour the hot water into the clogged toilet. Let the hot water sit for several hours or overnight to dissolve the clog.

This should slacken any clogs, but if you want to increase its effectiveness, repeat all the steps in the morning. Let the hot water sit for a couple of hours, then flush the toilet.

Method 3: Special Tools

If boiling water doesn’t do the trick, you can use special tools to clear a clogged RV toilet. You can either use a plunger or a drain snake.

  • Step 1: Prepare For Declogging

The first thing you want to do is to make sure that no liquid drips from the tank. Next, get a large bucket and place it under the dump pipe to act as a catch basin for any escaping liquid. Leave the dump valve open as you remove the sewer hose from the camper van.

  • Step 2: Use A Plunger

A toilet plunger is a great starting tool if you’re dealing with a minor blockage. Dive the plunger into the toilet. Push the plunger in and out until you find the clog. Make sure there’s enough water to cover the plunger.

If plunging isn’t enough, proceed to step 3, which is using a more complex tool – a drain snake.

  • Step 3: Use The Drain Snake

Place the drain snake into the dump pipe and wriggle it through the plumbing. Once it hits a clog, hook it into the clogged debris and twist it. Continue twisting until you feel that the debris breaks apart and goes into the holding tank.

Now, remove the snake and ask someone to close the valve as soon as you see any liquid escaping from the pipe. Finally, reconnect the sewer hose and do your usual tank dumping job.

Method 4: RV Tank Clog Solution

You can also try to fix a clogged RV toilet with chemicals. The chemical method is the best when combatting a very stubborn clog.

Pour the Drain Unclogger or the Dishwashing Liquid Option

If you use a tablet holding tank solution, you only need to drop a number of tablets into the holding tank. Let it sit for several hours or as recommended on the label.

For the liquid version, use the whole bottle of cleaning solution. Wait up to 27 hours to activate the cleaning agent. During this time, you’re not allowed to use the bathroom.

Alternatively, pour one cup of dishwashing liquid into the toilet, then follow with one cup of water softener and boiling water. Let them sit overnight. In the morning, flush the toilet to remove the clog completely.

Tips For Preventing Future Clogs

When you successfully unclog your RV toilet holding tank, you’ll want it to stay that way. Here are some safety precautions to keep the clogs away.

  • Use toilet paper that’s designed for RV use. This type of paper breaks down properly and won’t clog the toilet.
  • Dump your tank when it is ¾ full.
  • Use lots of water to flush down the toilet.


I hope you give any of these methods on how to unclog an RV toilet holding tank a try. All of them are pretty easy, provided that you follow the steps properly. If none of these unclogging RV toilet methods work, you should seek the service of a professional plumber.

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