Unclogging An RV Toilet

Learn how to unclog an RV Toilet whether you have a pyramid plug, compacted tank, clogged waste line, or misreading sensors Learn how to unclog an RV Toilet whether you have a pyramid plug, compacted tank, clogged waste line, or misreading sensors

If you’re dealing with a clogged RV toilet, then you’re experiencing a very common problem that we help RVers solve everyday. Nothing puts a damper on a camping trip like a backed up toilet, which is why we’ve put together this helpful guide.

There are multiple types of clogs and each type of RV toilet clog requires different methods to fix. We’re here to explain the types of clogs there are, and how to accurately diagnose your problem so you can fix it properly.

Follow along to learn how to diagnose the type of RV toilet clog you’re dealing with, determine the cause of the problem, get rid of the clog, and prevent clogs from occurring in the future.

Key Points About Unclogging An RV Toilet

  • The first step in unclogging an RV toilet is diagnosing the type of clog, and determining if it's caused by a pyramid plug, blocked toilet line, compacted tank, or misreading sensors.
  • Each type of RV toilet clog needs to be handled differently, so it’s important to confirm the type of clog you’re dealing with before taking action.
  • Misreading sensors may inaccurately indicate that you have a clog, when you actually don’t.
  • Preventing clogs in RV toilets is easy if you follow The Unique Method, and use the right products and the right processes in your RV.

Common Signs That Indicate You Have a Clogged RV Toilet

If your RV toilet or black tank is beginning to function abnormally, then it’s very possible that you may be dealing with a clog.

Common signs that may indicate that you have an RV toilet clog:

  • You try to add water to your black water holding tank through your RV toilet, but you can’t add anymore because your toilet bowl is backing up.
  • Your black tank shows “full” according to the tank sensors, but nothing comes out when you go to dump your tank.
  • You may be able to add more water to your black tank through your toilet, but when you go to empty your tank nothing comes out.

If you’re experiencing any of these issues in your RV, then it’s time to diagnose the type of clog you have, so you can take the proper action to fix the clog and get your RV toilet back on track.

Diagnosing What Type of RV Toilet Clog You Have

There are three types of RV toilet clogs you may be dealing with — pyramid plugs, blocked toilet lines, and compacted tanks. Each clog requires a different method to fix, so we’re going to help you determine which kind of RV toilet clog you have.

For more information about RV toilet clogs, we recommend reading our guide: 3 Common Types of RV Toilet Clogs You Should Know About

How to Diagnose Your RV Toilet Clog

Before trying to diagnose your RV toilet clog, we highly recommend being in a location with access to a sewer port, such as a full-hookup campground or dump station. This will give you the opportunity to do a more thorough diagnosis.

Steps for diagnosing your RV toilet clog:

  1. Add water to your black tank through your RV toilet bowl.
  2. Turn off all water sources to the RV.
  3. Connect the sewer hose to the discharge port of your RV.
  4. Open your black tank valve.
    • If water flows out of the tank when you open your black water tank valve, then you may simply have misreading sensors .
    • If nothing flows out of the tank when you open the black water tank valve, you may have a compacted tank .
  5. Shine your flashlight down the toilet for additional information.
    • Do you see the peak of a pyramid plug near the bottom of the pipe that connects the toilet to the black tank? If the answer is yes, you likely have a pyramid plug.
    • Do you see that the pipe is completely blocked off with paper debris? If the answer is yes, you probably have a blocked toilet line.
  6. Turn the water sources to the RV back on.

Once you’ve followed these diagnostic steps, you should be able to determine the type of RV toilet clog you’re dealing with. Next, we’ll provide details about the different types of RV toilet clogs, and how you can deal with them.

Types of RV Toilet Clogs & How to Deal With Them

Now that you know whether you’re dealing with a pyramid plug, blocked toilet line, compacted tank, or misreading sensors, we’ll provide you with more information about each type of RV toilet clog, and how to address each problem.

1. RV Pyramid Plug

RV Pyramid Plug Diagram. Unique Camping + Marine
RV Pyramid Plug Diagram

How to Clear a Pyramid Plug: Step-By-Step Instructions

If you’re dealing with a pyramid plug, let’s get rid of it with these easy-to-follow instructions.

  1. Turn off your RV’s fresh water supply.
  2. Using a flashlight to look into the toilet, check to see if the clog is completely blocking the 3 inch pipe that connects the RV’s toilet to the black water tank.
    • If the pipe IS completely blocked, proceed to step 3.
    • If the pipe IS NOT completely blocked, proceed to step 4.
  3. Take a section of ½” PEX pipe, or a toilet snake, and run it down the toilet to create holes in the top of the pyramid.
    • Create as many holes in the poop pyramid as possible so that you will be able to fill the tank with the maximum amount of water and treatment, allowing them to begin breaking down the clog.
    • If you have an on-board black water tank rinsing system, you can also use it to add additional water to the black water tank (after poking holes in the waste), allowing the treatment to break down the pyramid more effectively.
  4. Pour one entire bottle of Clear-It into the toilet bowl, and hold down the flush pedal so the product makes its way into the clog.
    • The goal here is to allow as much water and treatment to get to the clog as possible so that the clearing process can begin. The more you can fill the tank with water, the better.
  5. Let the product sit in the black water tank for as long as possible.
    • Make sure to let the Clear-It work for at least 48 - 72 hours before dumping the tank.
    • Depending on the size of the pyramid plug, it could take several days for the treatment to fully break down the pyramid. Clear-It will not damage tank components, so feel free to let it sit in the tank for days or weeks!
    • If the pyramid plug still looks large when you check on it after 72 hours, try poking more holes into it and adding more water to the black water tank.
  6. After at least 72 hours, or longer, dump your black water tank and confirm the clog has been removed, and water is now able to flow through your tank.
  7. Rinse your tank well to ensure all of the waste and toilet paper is broken up and out of the tank. Do this by filling your black tank, then dumping. Do this twice.
    • As you break down and rinse out the pyramid plug, it is sometimes possible for waste that has broken free to create a secondary blockage. If this occurs, you’ll need to restart the cleaning process and repeat steps 4-7 again .
  8. Once you’ve cleared the clog and rinsed your tank, close your black water tank valve.
  9. Turn your RV’s fresh water valve back on.

Important Note: When you are completely finished with the process, be sure to close your black water tank valve, and keep it closed unless you are actively dumping a full tank. Please refer to our guide about Why It’s Crucial to Keep Your RV Black Water Tank Valve Closed.

What is an RV Pyramid Plug?

Pyramid plugs, also often referred to as poop pyramids, develop slowly over time as waste and toilet paper accumulate into a pyramid shape directly below the RV toilet line. When this happens, the pyramid can become so large that it blocks off the pipe and prevents you from adding anything else into the tank.

How Do Pyramid Plugs Happen?

The most common cause of RV pyramid plugs is when RVers leave their black tank valve open when full-hookup camping.

While it may seem logical to leave the black tank valve open to allow everything to naturally flush out, unfortunately, when you do this, all of the liquid will flow out as expected, but all of the physical waste and toilet paper tends to remain.

As the toilet continues to be used, the waste and toilet paper can stack on top of itself until the pyramid grows so large that it creates a clog by blocking off the pipe.

For full details about pyramid plugs, we recommend reading our guides:

2. Blocked RV Toilet Line

Blocked RV Toilet Line Diagram. Unique Camping + Marine
Blocked RV Toilet Line Diagram

How to Clear a Blocked RV Toilet Line: Step-By-Step Instructions

If you have a blocked toilet line, the good news is that clearing this type of clog may be as easy as using a toilet plunger, in the same way that you would at home. Even if the plunger doesn’t work, the process for clearing a blocked RV toilet is very simple.

  1. Turn off the supply of fresh water to your RV.
  2. Hold down the flush pedal.
  3. Use a toilet plunger to attempt to force the blockage out of the toilet line, similar to how you would at home. We like this plunger.
    • If the plunger clears the blockage, proceed to step 8.
    • If the plunger doesn’t clear the blockage, proceed to step 4.
  4. Hold down the flush pedal and pour one entire bottle of Unique Clear-It into the toilet bowl.
  5. Let the treatment sit in the toilet overnight, or longer.
    • Some clogs may be broken up in as little as a few hours, but for the majority of clogs, you can expect Clear-It to unclog your tank in 12-48 hours.
    • Stubborn clogs may require 72 hours or more. There is no amount of time that is too long to let the treatment sit, the longer the better!
  6. Try to plunge the toilet again in the morning.
    • If the clog is cleared, proceed to step 8.
    • If the clog is not cleared, proceed to step 7.
  7. Using ½” PEX pipe, or a toilet snake, try to break up the clog: push it down the line until it breaks through to the black water tank.
  8. Once the blockage is cleared, turn the fresh water supply back on: hold down the flush pedal for a while to make sure residual residue and debris are cleared from the pipe.
  9. Dump the black water tank.
  10. Thoroughly rinse the black water tank: fill it completely with water and then dump the tank.

What is a Blocked RV Toilet Line?

Blocked RV toilet lines, or clogs in black water plumbing in general, occur more quickly than other types of clogs. These clogs happen as waste and toilet paper move through the relatively narrow plumbing pipes and create a blockage.

How Do Blocked Toilet Lines Happen?

The most common cause of blocked toilet lines in RVs is flushing too much toilet paper, and not enough water down the toilet.

Blocked plumbing lines are more likely to occur when the black water tank isn’t positioned directly below the toilet, and the paper and human waste have to travel through long lengths of pipe that may include turns and elbows in the plumbing, or because waste must travel between two black water tanks.

For full details about how to deal with RV blocked toilet lines, review our guide: How to Unclog a Blocked RV Toilet Line

3. Compacted RV Black Water Tank

Compacted RV Black Tank Diagram. Unique Camping + Marine
Compacted RV Black Tank Diagram

How to Clear a Compacted RV Black Water Tank: Step-By-Step Instructions

If you’re dealing with a compacted RV black water tank, let’s unclog it with some easy-to-follow instructions.

  1. Close your black water tank valve.
  2. Fill your black water tank with as much water as possible.
  3. Pour one entire bottle of Unique Clear-It down the toilet and into the black water tank.
  4. Let the full tank of water and Clear-It sit for at least 72 hours, or longer.
    • We always recommend letting Clear-It work for at least 72 hours, but for more severe clogs, you may need to let the treatment sit for much longer.
    • Stubborn clogs may need Clear-It to work for several days beyond the initial 72 hours to fully break down the clog. There is no amount of time that is too long to let the treatment sit as it will not damage tank components in any way, in fact, the longer, the better!
  5. Open the black water tank valve and dump the tank.
    • If nothing comes out, close the black water tank valve again and let Clear-It work for longer. Again, the more time you give Clear-It to work, the more successful the treatment will be.
    • For really severe clogs, you may need to use a PEX pipe to manually break up some of the waste to loosen it and allow the rest to flow out.
    • If liquid comes out, dump the black water tank.
  6. Close your black water tank valve.
  7. Rinse your tank well to ensure all of the waste and toilet paper is broken up and out of the tank. Do this by filling your black tank, then dumping. Do this twice.
  8. Once you’ve cleared the blockage, close your black water tank valve.
    • Make sure to keep your black water tank valve closed unless you are actively dumping your tank.

Important Note: While the process to clear a compacted black water tank is simple, it does take time for the treatment to work. If time is an issue, then hiring a tank cleaning service can dramatically reduce the time it takes to clear a clogged black water tank.

These services use specialized cleaning tools to do the job in a few hours, rather than in several days or weeks. However, the tradeoff is the price – companies can often charge upwards of $500 for this type of service.

What is a Compacted RV Black Water Tank?

Compacted tank clogs occur when an RV black tank has a large amount of waste that has hardened inside the tank. When this happens, solid waste blocks the exit and nothing can flush out of the tank when the black tank valve is opened.

How Do Compacted RV Black Water Tanks Happen?

The most common cause of RV compacted tank clogs is when the RV has been in long term storage with a full, or partially full, black water holding tank.

As the RV sits in storage, the liquid evaporates from the black water holding tank, leaving behind a brick of waste and toilet paper that creates the clog.

Additionally, not using a high-quality, waste-digesting treatment or a leaky discharge valve can be other causes of compacted black water tank clogs.

For full details about compacted tank clogs, we recommend visiting our guide: How to Unclog a Compacted RV Black Water Holding Tank

Misreading Sensors & RV Toilet Clogs

Occasionally, holding tank sensors that are covered with waste, toilet paper, and debris (black water tanks), or grease and oils (gray water tanks), can misread and falsely lead you to believe you have a clog.

Misreading sensors can indicate that the black water tank is full, but then nothing comes out when you open the black water tank valve. This could signal that you have a compacted tank, but it could also mean that you simply have an empty tank with sensors falsely reading that the tank is full. In some situations, it is even possible that you’re dealing with a clog and misreading sensors at the same time.

Fortunately, resolving these issues is relatively easy. For help with misreading sensors, refer to our guide: How to Clean and Restore RV Holding Tank Sensors

How to Prevent RV Toilet Clogs: The Unique Method

By far, the best way to prevent RV clogs and wastewater issues is with The Unique Method.

Developed over 30 years of professional RV wastewater treatment experience, The Unique Method is tried, and tested, to provide RVers with problem-free holding tanks. While no solution works like magic, following the simple methods outlined in The Unique Method allow you to break down waste, eliminate odors, and prevent sensor probe problems, simultaneously.

The key components of The Unique Method are twofold: 50% is following the right Process, and 50% is using the right Products. We always recommend using our Unique Products as part of this proven process, because they are specifically formulated with The Unique Method in mind, providing you with the best-possible results.

For a comprehensive list of tips about how to prevent RV toilet clogs, we recommend reading our guide: How to Prevent Clogs in Your RV Black Water Holding Tank.

Expert Support: Unclogging RV Toilets

If you’ve followed the entire process above and are still experiencing issues with a clogged RV toilet and black tank, don’t hesitate to reach out.

Our expert Customer Support Team is ready to help you fix problems and get your tanks back on track.

Toilet Clogs Be Gone: Your RV is Road-Ready

Whether you were dealing with a pyramid plug, blocked toilet line, compacted tank, or misreading sensors, after reading this guide you should be able to get your RV toilet flushing like new.

Remember, by applying the right process (The Unique Method) and using the right products (Unique Clear-It), you can prevent the majority of RV toilet clogs before they occur, allowing you to enjoy worry-free RVing year-round.


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Unclogging an RV Toilet Field Guide. Unique Camping + Marine
Field Guide

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