How to Unclog an RV Toilet (Simple DIY Steps)

Nobody likes to think about toilet cleaning; it’s one of the least appealing jobs in the home, never mind the RV, but it’s even more important in the RV for health and safety. The best way to unclog the system is to read on and choose the method that suits you best!

How do you know your black tank is clogged?

The black tank is responsible for storing the wastewater in the RV until it can be flushed using a sewer connection. Conventional advice says that you should regularly clean the black tank, but it still might clog. If the black tank fills up too quickly or doesn’t drain properly, it’s clogged.

Why is your RV toilet not flushing?

When you’re on the road, the last thing you want to encounter is a clogged RV toilet – but it’s a common occurrence. While you might have to put up with unpleasant smells for several miles, you can fix RV toilets by closing the tank vent and adding some suitable chemicals.

Solid-to-liquid ratio

If you want to know how to unclog an RV toilet when you reach your destination, check the solid to liquid ratio first. This is one of the most common types of blockage in a clogged RV toilet. In general, RV toilets should have three liters of water for an eighteen-liter holding tank.

The toilet paper you use

It might seem gross to put toilet paper into a special wastebasket rather than into the toilet, but it’s worse when the toilet becomes clogged and starts to smell. One way an RV toilet bowl clogs is due to the toilet paper used, so choose degradable paper or put a bin in the bathroom for paper.

Your black tank valve is open

The black tank valve on your toilet should always be closed unless you are evacuating the waste from the holding tank. Leaving it open dries the waste and prevents bacteria from breaking it down; additionally, it causes a waste pyramid that clogs the toilet drain.

The weather

In cold weather, your RV toilet might not flush due to the freezing conditions. Water in the tank becomes solid, making flushing impossible unless you own a four-season RV. In hot weather, your toilet may not flush because of evaporation from the flush water tank.

The spray nozzle is clogged

The spray nozzle of an RV toilet is designed to improve the flush capacity of the unit and clean the toilet bowl. Unfortunately, this nozzle can become clogged due to debris that dries in during hot weather. This spray nozzle can be unclogged using boiling water or a flexible tank wand.

How a camper toilet gets clogged

Don’t take your RV toilet for granted! This unit is a necessity, but it requires proper care to function correctly and avoid becoming clogged. The main reasons for clogging include non-dissolving toilet paper, an open waste pipe, and ineffective chemicals.

To prevent these issues, you need to check your toilet regularly and use a dedicated RV toilet paper or avoid paper completely.

RV toilet system diagram

An RV toilet system consists of a toilet unit with a toilet seat and flusher, which is usually on the floor. The unit leads to a black water tank underneath, which is sometimes called a holding tank, where wastewater is kept. A pipe leads out of the black tank and into a sewer on site.

How do you unclog an RV toilet vent?

A clogged RV toilet is not only inconvenient, but it is also unpleasant; toilets clog up for a variety of reasons, but if the vent is also clogged, it pushes more of the odors from the holding tank into the vehicle. Ensure your RV vent is not clogged and you have a suitable vent cap.

Method 1: Using black tank cleaners

Tools and equipment needed

• Black tank cleaner
• Gloves and mask 

Step 1

The first step is to identify the blank tank cleaner that suits you best. Choose from liquid, capsules, or powder. Some of these cleaners might be easier to use than others, and you might have a preference for one over the other. Still, they will all be effective for cleaning the tank.

Step 2

Once you have your black tank cleaner, it’s time to use it on your clogged toilet. First, close the grey water tank valve to store up water from the shower and sink in the grey water holding tank; this will be used to flush the sewer pipe after you have cleaned the black tank.

Step 3

The off-the-shelf black tank cleaner has a special combination of chemicals that breaks down the solid waste and dissolves it, preventing odors from building up and escaping through the vent. This is always a concern when your RV toilet clogs.

Step 4

Leave the solution in the tank to take effect; this might be overnight or a few hours, depending on the solution and content. When you’re ready, connect up the black tank vent with the sewer system and flush it out. Use the greywater to clean the pipes.

Method 2: Using a plunger

Tools and equipment needed

• RV Plunger 
• Black tank chemicals 
• Gloves and mask

Step 1

A toilet is a toilet, right! If you have a clogged toilet, why not get the plunger from your home and unclog it with a few pumps? Unfortunately, it’s not that easy. An RV toilet doesn’t have the same size bowl; still, you might be able to use an RV plunger – get one online.

Step 2

If you are going to use a plunger to unclog a toilet, first use some hot water to soften the blockage in the pipe. Most of these toilets block up at the vent rather than the pipe, but blockages still happen in the pipe as well and need to be fixed. Place the plunger over the pipe.

Step 3

Next, use the plunger as you normally would; after a few pumps, check the pipe to see if the blockage is still there. If it is, you can repeat the previous steps using some more hot water. Alternatively, put some of the black tank cleaners down the pipe and wait for them to take effect.

Step 4

Some toilets in RVs have a longer pipe system than others that can become jammed up if there is too much toilet paper in the system. Use a plunger to unjam the paper, then treat the black water tank as you would normally. Remember to use less toilet paper when you’re in your RV.

Method 3: Using ice cubes

Tools and equipment needed

• An bag of ice cubes 
• Gloves and mask

Step 1

There’s no need to order lots of expensive gear from the internet if you have a clogged black tank; all you have to do is make some ice cubes and put them into the toilet in your vehicle. The ice cubes go into the black water tank and start to break up the blockage as you drive.

Step 2

That’s right; this method is a little more hands-on; the good news is that it’s a lot cheaper and more fun as well. Take your RV for a drive, and don’t be afraid to hit the road bumps – at this stage, the more sloshing, the better; the hard ice cubes are perfect for breaking down waste.

Step 3

After about half an hour of this, return to the dumpsite and hook up your tank. The hard ice should have broken down the solid waste allowing you to drain the tank and freshen it up. Additionally, the ice helps to increase the water in the tanks for drainage.

Step 4

If the process has worked, you should be left with an empty tank, but you don’t want it to clog it up again when you hit the road. Start by treating it with black tank chemicals that break down the waste and prevent it from smelling. Also, avoid using non-dissolving paper.

Method 4: Using hot/boiling water

Tools and equipment needed

• A kettle 
• A mask 
• Some gloves

Step 1

Hot water is also very effective for cleaning the RV wastewater system. Although it doesn’t break down the waste as hygienically as chemicals, it is very effective for demolishing built-up paper that clogs up the vents and pipes. So fill the kettle and switch it on.

Step 2

Put on your mask and gloves! When you pour boiling hot water to unclog an RV toilet, you are sure to encounter some appalling odors. Try to pour all the water into the tank at once, so it has a chance to break up the paper and debris that is clogging the tank – leave for an hour.

Step 3

Boiling water is effective for cleaning a black water tank; however, you will probably need more than one kettle to make a difference. Toilets in RVs are made of hard, durable plastic that won’t melt at high temperatures; still, take care when pouring the kettles.

Method 5: Using soapy detergents or Vaseline

Tools and equipment needed

• Dish soap 
• Vasaline
• Gloves and mask

Step 1

If you have a clogged black water tank, there is an easy and affordable way to solve the issue. Instead of using expensive cleaners and equipment, all you need is some dish soap and vaseline. These items are easy and affordable to acquire. Add a full bottle of dish soap to your black tank.

Step 2

The dish soap will help break down the solid matter in the tank and drain the tank more easily, but you can also put in a large helping of Vaseline that coats the side of the tank and prevents the waste from sticking to the sides.

Step 3

Once your black water tank valve is clear and you have evacuated the tank, you can add some more dish soap and Vaseline to coat the sides of the tank further and make the RV’s black tank smell nicer.

Method 6: You can also snake an RV toilet

Tools and equipment needed

• Toilet snake 
• Mask and gloves 

Step 1

Toilets in recreational vehicles come in different shapes and sizes, most often, they don’t require a plunger or snake, but some have a pipe system that clogs up. First, buy an RV snake.

Step 2

Once you have an RV snake that suits your needs and budget, it’s time to use it to clean out the system. Place the snake into your toilet cistern and use the line to unblock the pipe.

Step 3

If your toilet is clogged up with dry waste, the snake will clear the pipe and allow you to use the toilet or put new chemicals into the black water tank.

Step 4

Once the cistern is clear, you can remove the snake and drain the tank. It’s always a good idea to drain the tank right away and treat it with chemicals.

Pro tips for preventing clogged RV toilets

• Keep waste tank closed except when dumping
• Perform regular maintenance on the vehicle’s toilet
• Avoid using hard or too much paper in the toilet
• Use extra water in the tank
• Coat the tank with Vaseline or dish soap.