If you hear gurgles in your toilet, it means that air is escaping the pipes. If you hear water bubbling in your toilet while you finish your wash cycle, then that means your washing machine is pushing air through the tube. 

The first thing you need to do if there is bubbling in your toilet when your washer is draining is to seal off all your drains, make sure there is no clog in your community’s sewage system, and then make sure there are no clogs in your own system.

Finally, to stop your toilet from bubbling, simply install a 2-inch drain with a P-trap. If this does not help, then you should go on to the roof and spray water into the main vent stack to clean it out.

Reasons Why Your Toilet Bubbles When Your Washer Drains

Blocked Vents

The most common cause of bubbling in your toilet is due to blocked vents. Even if only one of your vents is blocked, this can create negative pressure, resulting in bubbling. 

This occurs because water forms a seal around the pipes, which results in a vacuum. Because this vacuum is extremely strong, it will create a gurgling sound. Additionally, if this occurs, you may expose the bathroom to sewer gases resulting in bad odor.

Partial Clogs

One simple reason for why your toilet may be bubbling is because the main drain on the washing machine has a partial clog. This can easily cause it to bubble, because when the machine drains, the water path is restricted. This will force air and water to go back through the pipe, and bubble.

When this backflow occurs, sink drains may not be affected, but you will hear the gurgling in your toilet.

Connected Drains

Another reason that will cause bubbling is that the fixture might be between the soil stack and the toilet. This can make the drain from the washer, connect to the drain of the toilet. Another option is that a fixture and the toilet can tie into the same stack. This is called “wet venting” and this can cause bubbling.

Clogged Vent Pipe

All bathrooms have vertical pipes that go to the roof in order to vent. One mistake that most contractors make when installing vent pipes, is that they do not have a cover. This can allow dirt and debris to fall into it. When this vent becomes clogged, it does not allow air to escape.

In order to allow the water in your home to drain properly, you need airflow. The same goes for sinks and tubs, but for toilet and washer vents you need a much higher amount of airflow.

When the pipe gets clogged, it will force the air out of the nearest opening. Often, this is a toilet drain, hence the bubbling.

Washer Drain Malfunction

If all of the other problems do not ring true to your situation, then you need to see if your washer drain works properly. The reason that the bubbling occurs in your toilet is that the washing machine releases air very quickly and under a lot of pressure.

If your washing machine drain is malfunctioning, it may be because it is not properly installed. The issue is that most people do not pay much attention when installing pipes. If this is not done by a plumber, then you may run into issues later down the road. 

When installing washing machine pipes, not only do the pipes need to be the right size and diameter to function properly, but they also need to be set up properly. If not, the air will never reach the pipes, and then bubbling will occur in the toilet.

How Your Drain System Works

Your plumbing system consists of two small systems. 

  1. Used to bring fresh water
  2. Use to take out the wastewater

When water comes into your home it needs to go through a meter that measures how much water you have used. Next to this meter, you should also find an emergency valve. If you have a pipe break, it will flood your home. 

Your drain system consists of various traps, vents, and cleanouts. 

  • Vents: Allow air to enter, without these wastewater cannot leave your home.
  • Traps: Found below every sink. Every fixture must have a trap. Note that toilets are self-trapped.
  • Cleanouts: Allows wastewater to leave your system.


If any component fails, your entire drain system will be affected. 

Steps to Take if Your Toilet is Bubbling When Your Washer Drains

Seal Off the Drains, Then Plunge the Toilet

If the cause of the gurgling is within the drainpipe, then you may be able to fix the problem by plunging the toilet. This might allow you to fix a moderate clog. Since your bathtub, sink, and the shower is connected to the same drain, then you need to seal all of these drains off before plunging.

  1. Seal off these drains with duct tape.
  2. Begin to plunge with the toilet full of water.
  3. Fit the head of the plunger fully on the bottom of the drain hole.
  4. Pump 10-15 times.

Go Deeper to Find and Remove Clogs

If you still have bubbling in your toilet, then you will need to go deeper remove the clogs. 

  1. Take either a plumber snake or an air bladder. Either of these can be purchased from any hardware store.
  2. According to the package instructions, force clogs from the drain into the larger pipe.
  3. This will open the flow of water, and should immediately solve the clog.

Ask Your Neighbors to See if There is a Community Sewer Problem

Sometimes there is no clog in your personal drain, but rather a clog in a community sewer line. This can create bubbles in your toilet as well as your neighbors’ homes. If this is the case, you can call your municipal sewer authority and report the problem. 

Check and Clear the Vent Stack

After attempting the other fixes, you will need to move on to investigating your vent stack. Because your drain system requires a large amount of air, your vents may be the culprit to your problem. To check the vent stack you will need to go on the roof. Be extremely careful if you plan to do this yourself.  

  1. Take a strong flashlight, a thin rope, duct tape, and a garden hose.
  2. Duct tape a flashlight to the end of a rope, turn it on, and place it into the pipe that is on the top of your roof.
  3. You should be able to see in the top 10 feet of the pipe.
  4. Look for clogs, this might be leaves, debris, or even a small animal that has been stuck.
  5. Remove this debris with either a coat hanger if possible. If not, deep clogs can usually be flushed out by pouring water from your hose into the pipe.

If you cannot remove the clog, then you will need to call a professional.

Related Questions

If I can’t remove the clogs from my sink or vents, what should I do?

In the case that you cannot remove clogs, you should call a plumber. You run the risk of breaking things in your drainage system if you do them improperly, so it is always good to bring in a professional.