Why Does My RV Toilet Bubble When I Flush?

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RV toilets are no doubt a necessity when taking a trip to the outdoors. They maybe aren’t on everyone’s mind, but it can be concerning when they start acting up. What happens, for example, if an RV toilet starts to bubble? What does that mean? In this article, we have researched to answer this question for you!

If your RV toilet bubbles when it is flushed, it isn’t a good sign. Typically that means there is some blockage within the drain or tank. When this happens, it is essential to inspect your toilet and take it to a professional when possible.

It might be hard to completely fix an RV toilet while you are in the outdoors. However, you might be able to pinpoint the problem at least. This article will discuss the possible culprits as to why your RV toilet bubbles when it is flushed. In addition, we will look at how to fix the issue possibly, so read on!

Modern Motorhome Bathroom, Why Does My RV Toilet Bubble When I Flush?

Why Does My RV Toilet Bubble When I Flush?

A bubbling sound when you flush the toilet in your RV is usually not a good sign. It can be due to several different causes, but all are related to low water flow into the bowl. Low water flow is more than likely due to some RV toilet blockage. 

According to most RV owners, a toilet bubbling is a sign of some blockage. Pressurized water lines will cause the bubbling effect because they force air into the drain line, which escapes through small holes around the bowl’s rim. “Flappers” cover these holes and let water through as you flush the toilet but otherwise keep anything from going down those holes.

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Bubbling at the Fill Valve

The fill valve has a rubber flap on top that closes and traps air until the tank is filled to that point. Then the flap opens to let water into the bowl. If that rubber flap is damaged or worn out, air can travel into the drain line every time you flush. That will create bubbles for sure since there’s no way to stop it except by replacing the valve.

Bubbling at the Waste Valve

Similar symptoms occur if any of the rubber components in the waste line are worn. If you have a subtle bubbling at the toilet when it is flushed, it might be coming from where the water enters the tank. The section of hose between your city water connection and the actual fill valve can get aged and cruddy, causing bubbles to enter the bowl.

Sometimes the best way to find bubbles in the bowl is to let the water out of the tank or remove the cap from the toilet. Watch where it comes from, and you will have found your problem area.

Bubbles in the Toilet Bowl

It’s not unusual for a toilet bowl to bubble a little, but if it is happening after you flush, then you’ve got a real problem. Bubbles like these can occur if there’s air in the line or trapped water in the bowl after flushing. The pressure makes those bubbles, and they come out of the tiny holes all along the rim and through other openings like around the handle and at the hinges on top.

Just let it work its way through, and you’ll see the bubbles go away. Draining the bowl will help, too, as well as flushing again to clear the line out. Replacing a toilet fill valve or ballcock assembly can solve this problem quickly and inexpensively.

There is also another possibility that may be causing your water problems – a cracked bowl. Unfortunately, cracks are challenging to find unless you know the trade tricks, so it is best to have a professional look into this issue for you.

You can avoid all sorts of problems with your RV toilet by keeping an eye on water usage and keeping things clean around the valves and lines. However, if you ever experience significant problems, always remember that replacing parts is probably the best option.

How do you fix a toilet that bubbles when flushed?

For this, you need to know the source of the problem. For example, the cause of bubbling can be air in the waterlines, trapped water in the bowl, or problems with replacement parts.

If there is dirt where your city hookup attaches to your RV, that will cause bubbles every time you flush. An excellent way to tell if it is coming from that connection is to turn it off and drain the water in your RV.

If bubbles are still present after the tank has drained, then you will need to check for bubbles at your toilet. If there are no more bubbles after draining, it is time to troubleshoot the city connection first.

clean white toilet seat for an RV

Troubleshooting city water first

Turn off your inside valves and open up your drain valves under your sinks to troubleshoot the city connection. Doing so will release most of the pressure from inside your lines. Next, open a hot and cold valve at the external connection to relieve any built-up water pressure in those lines.

Next, go back to your toilet. If you still see bubbles coming from the bowl when it is flushed, then there’s a problem with your tank parts (the flush valve or flapper).

If there are no more bubbles in the bowl after opening all of the valves, go ahead and turn on your city water again. Check for any leaks around your city hookup and check the pressure on your water pressure gauge. If you do not have a gauge, you need to check for leaks or pressurize your lines with an air compressor.

If there are no more bubbles and no leaks around the city connection, then it is time to troubleshoot your toilet.

Troubleshooting the toilet

To troubleshoot the toilet, turn off your power to it. This will ensure that you do not get shocked when looking for potential problems. Next, inspect around the fill valve and look for cracks in its tank. If there are no leaks or cracks at the fill valve, check for bubbles around where it attaches to the bowl. Check for more bubbles in there, and if there are, you may need to replace the fill valve.

If you do not find any problems around the fill valve or on the bowl, open up your tank and look for cracks in the bowl. Replace if needed. If that is not necessary, then go ahead and turn it back on again. Your water should be ready for use now.

Can you use a plunger in an RV toilet?

It is possible to use a plunger in your RV toilet. However, there are things you need to know about doing so before you begin plunging. First, it is essential to make sure you put some water in the toilet before starting to plunge. Second, do not plunge the toilet when the bowl is empty!

If you are using a sink plunger, remember that it has smaller rubber lips than toilet plungers. You can use this plunger on your RV toilet, but you will need to proceed carefully because the edges might not seal correctly. Make sure that there are no leaks around the plunger before you start plunging.

Camping van interior cabin RV bathroom

What does an RV vacuum breaker check valve do?

An RV vacuum breaker check valve prevents water from siphoning out of your pipes when you are not hooked up to city water. The best place for an RV vacuum breaker is in the gray water system to not interrupt freshwater use. This keeps harmful bacteria from getting into the hoses or water systems.

If your vacuum breaker is outside, make sure it is below any faucets or other outlets so that water will not siphon out of it when you don’t have a water connection. If your vacuum breaker is inside, make sure it is below the height of any sinks or other fixtures to prevent siphoning while you are using them.

How do I change the vacuum breaker on my RV toilet?

Changing the vacuum breaker on your RV’s toilet is essential if you have no water pressure. It also helps if there is a lot of water running through your lines and you have been dealing with clogs.

To change the vacuum breaker, find where it attaches to the tank supply line or fills the valve supply tube. Then, disconnect the supply line or supply tube. Take it off and discard it carefully because you cannot attach a new vacuum breaker to an old hose.

Attach the new vacuum breaker to the fill valve supply tube or tank supply line and tighten up all parts as well as possible before checking for leaks. Next, turn on your city water again and see if there is any water coming from the vacuum breaker or coming out of your toilet. If you do not have any leaks and there is no water coming from the vacuum breaker, you can now turn on your freshwater and test it out.

In Closing

Overall, doing repairs on your RV toilet isn’t the most exciting DIY project. However, it may save you some money vs. having a professional do it. Nonetheless, if you feel overwhelmed, then take it into an RV mechanic shop for help.

Check out more articles on RV’s here:

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