Why Does Your Toilet Bubble When the Washing Machine Drains?

It may be puzzling to see air bubbles emerging from your toilet if you are not familiar with plumbing structures. Surprisingly it is a pretty common occurrence, as there are many possible sources for this peculiar issue.

The most common reason for your toilet bubbling as your washing machine drains is a clogged vent stack. This type of clog causes negative air flow, causing bubbles of air to appear in your toilet. This can be solved by clearing out the vent stack and the toilet itself to ensure there are no blockages in this system.

Although a bubbling toilet does not seem threatening, it is a sign that there is a clog or leak somewhere in your drain pipe system. It is best to fix this problem quickly to avoid bigger issues down the road. Follow along with this article to learn how to identify the source of these bubbles and what you can do to solve it on your own!

What is causing your toilet to bubble? 

The drain pipes in your home are all connected, which is why your toilet can bubble when your washing machine drains. So there are a lot of sources of this bubbling, but they can be pretty easy to identify. Here are the most common explanations for this issue.

Full and partial clogs 

The waterlines between your washer and your toilet (and sometimes your bathtub drain) are connected. However, the main issue could just be related to a clogged toilet! The clogs could be partial and easy to clean out, or a bit larger and further down the drain. Items like tampons, toys, or other large materials can block up the drains unsuspectingly, causing them to bubble when the washer drains.

Vent stacks are clogged

Vent stacks are important for maintaining air pressure in the pipes of your home. If these get clogged, negative air pressure can force air to come up in unexpected places. It is not a major problem, but one that can easily be fixed!

When the vent pipe is blocked it causes negative air pressure can develop in the drain pipe. This will cause the air to pull from wherever possible, including the water in your toilet. Water forms an airtight seal inside the pipe, which is why the air pull usually comes from this spot.  

This is the result of a clogged vent stack, but what causes it? Leaves, snow, sticks, or even small animals can all clog up this vent. To fix it, you will need to go to your roof and find this vent stack. Hopefully, you can clear out the debris with your hands, but some long tools may be needed if the clog is too deep to reach.

The P traps are clogged

A toilet P-trap is a curving channel inside the base of a toilet that leads from the hole at the bottom of the bowl to the drainpipe. This can be backed up with debris and cause your toilet to not drain correctly. It is a very common explanation for a bubbling toilet!

Most of the fixtures in your home drain out of the same drain pipe. If you notice that your sink or tub is draining fine, the clog is likely in the toilet, and not in the overall sewage system.  

Pipes were installed incorrectly 

To put it simply, incorrectly installed pipes can lead to both air and water leaks. Which can cause air to bubble up to your toilet, especially if your washer is draining. This often comes from people adding washer drains as an afterthought and forgetting to install a P-trap.

Without this corrected air pressure, the rouge bubble can find its way into all of the drains in your home. However, it is easiest to spot in your toilet. If this is the problem, it would require some major repairs to your home’s pipe system. In this case, it is best to call in a professional to see what should be done.

The city sewers could be the problem 

Another possibility is not an issue with your home, but with the city in which you live! If you have checked all the possibilities for blockages and nothing seems to be the issue, your city’s sewer could be clogged. There is not much to do about this situation, other than to call the city offices and alert them of the possible issue. 

Five steps to fix a bubbling toilet 

There are several ways you can try to fix your bubbling toilet. If you are not sure what the issue is, it’s helpful to complete each measure on this list in order. And if the issue is not resolved afterward, you should call in a professional. 

Plunge the toilet 

The first step is the all too familiar action of plunging the toilet! This will fix moderate clogs in your drain pipe and toilet. You can use a regular plunger or a drain snake to see if the clog is further down. A helpful tip is to seal off the drains before you do this by putting stoppers in your other drains. This will keep the sewage from flowing in your sink and tub.

Unclog the sewer 

If you have plunged into the toilet for a long time and it does not seem to work, you will have to try something else. This will allow you to reach a clog much deeper than a plunger can reach and ensure it is completely cleared out. It is easy to find an air bladder or plumber snake at the hardware store to utilize at this step. These tools will force the clog to drain and open the water flow in your toilet. 

Drain the hoses 

Step three is to drain the hoses of your washer. If you have cleared the toilet drains, then it is likely the washer’s drain that is causing the issue. This is easy to identify if the washer is draining slower than it should. You should also consider installing a P-trap at the base of your washer drain. This can help prevent future issues like this from happening again, and easy to do if you are already working on the area. 

Clear the vent stack

As we mentioned before, the negative air that is bubbling in the toilet can be caused by a clogged vent stack. Find the vent stack in your home and grab a ladder to climb to your roof. You can use a flashlight to look for clogs in this vent pipe. 

You may find leaves, rocks, small animals, or even bird nests resting in this vent stack. Do your best to clear all of it out so the vent can work properly. It is also best to replace or install a vent pipe cover. That way you do not have an issue like this in the future!

Install new pipes or a drain  

If nothing else seems to work, it is probably time to call a professional plumber and consider installing new pipes. This should be the very last step, as it is unlikely the source of this simple issue. Since professional plumbers and new installations are expensive, you will want to check everything else before spending the extra money if it is not necessary.

Know the Specs for toilet pipes 

Having a basic understanding of your toilet is important in being able to identify issues within its overall system. It makes it easier to solve this issue, a bubbly toilet, and others down the road. So here is a quick rundown of the basic specs of toilet pipes you should know!

Toilet Drain Pipe 

The toilet drain pip stretched from the end of the toilet base to the home’s overall drain line. These tend to be about 4 inches in diameter so that they can allow more waste per unit to prevent constant clogging. If your pipe is closer to 3 inches, then you will see more basic clogs in the future.

Drain Line

The drain line is the overall drain system that all pipes in your home connect to as the water finds its way to the sewage system. This transports all the wastewater in your home, from toilets, sinks, dishwashers, washing machines, and showers! It is not as common, but this pipe can get clogged with debris from drains. However, most toilet clogs occur in the actual toilet drain.

Toilet Closet Bend 

Finally, there is the toilet closet bend. This is an elbow-shaped part that is the connection between the toilet and the main drain line. It allows the flush to change 90° in its direction to properly meet up with the drain line. This is a common place for clogs due to their sharp angle.

Should you call plumbers or DIY? 

DIY steps and tools 

Many of the solutions in this article can easily be done on your own! Clogs in the toilet or vent stack can be cleaned out with only a few extra tools. Deeper clogs may need assistance from professionals, but there are plenty of solutions you can do yourself before deciding on a plumber’s assistance. 

Plumbers have the expertise 

The majority of people do not know the first thing about plumbing, which is why professional plumbers are in high demand and so highly paid. If you have gone through all the solutions you can think of, calling a plumber will help fill in the prices you are missing. The schooling has prepared them to know the root of the problem and how to solve it quickly!

Plumber costs vs DIY 

If the issue is a simple clog in your system, you will only pay about $30 if you have none of the proper equipment. But if you a p-trap or a plumber’s assistance installing it, you will pay a lot more. Plumbers usually work for $60 – $200 an hour, so you could be paying alot depending on the problem and how long it takes them to fix it!

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