What To Know About Why Your Toilet is Bubbling

Last Updated On June 22, 2024

Updated on January 11, 2023



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why is my toilet bubbling

Did your toilet just gurgle out of nowhere? 

If you’re asking, “why is my toilet bubbling?” it’s usually a sign of a clog somewhere in our sewer system. 

You don’t need to call a plumber just yet. While a bubbling toilet could be a plumbing emergency, it could also be a quick DIY fix. 

The noise might not annoy you too much at first, but it could escalate into a much larger sewer line problem very quickly. Let’s talk about how to troubleshoot it.

What's In This Guide?

      Possible Causes For Why Your Toilet Is Making Bubbling Noises

      Our toilet is connected to a sophisticated drainage system inside our walls and under the foundation of our home.

      Sewage can flow down the sewer pipes without resistance using gravity and air pressure. The negative air pressure is then forced up and out through the vent stacks on the roof.

      If any part of this system is blocked, it could create one of two problems.

      The first sign is a gurgling sound from random areas of the home, explaining why our toilet is making bubbling noises. 

      This can happen when the area responsible for venting gets blocked. Air will always seek out the path of least resistance. In this case, our commode. 

      The clog can eventually make it to the drains in our walls or even the sewer lateral pipe in our yard. With nowhere for the wastewater to go, it could start backing up in our toilets, showers, or sinks

      After a quick diagnosis, we might find that the block is within reach and could be a quick DIY fix. 

      Here is a video to explain everything there is to know about what your toilet is bubbling. 

      Why Is My Toilet Bubbling When The Shower Is Running

      Water flowing through the sewer pipes can create a vacuum effect in the drainage system. The harmful sewer gas forces through the pee trap and out of our toilet. 

      If there is a stubborn blockage between our shower and the main sewer line, this could be either a clogged drain deeper in the system or a blocked vent stack

      Our toilet bubbling with the shower running might not be too big of a concern at the moment. It might even clear itself in time. 

      It could also result in a big problem down the road and costly repairs. 

      To save ourselves time and money in the future, it’s important that we investigate the problem sooner rather than later.

      Why Are My Toilet Bubbling And Shower Slow Draining?

      We’ve all cleaned out a hairball when we notice our shower draining slowly. We also know that a toilet bubbles when negative air forces its way out of our toilet bowl rather than the vent pipe.

      What happens when we notice both things happening at once? We’re probably asking ourselves, “Why are our toilet bubbling and shower slow draining at the same time?” 

      The good news is that we probably don’t have two separate problems. These two issues are most likely related to the same clogged line. 

      When something is restricting the negative air pressure from escaping, this also prevents anything from being able to flow down the main sewer pipes freely. 

      The more serious the blockage, the slower the shower will be to drain. 

      This helps the troubleshooting process as it informs us that our toilet and shower most likely share a drain line and vent stack. This process is known as wet venting in plumbing

      Why Is My Toilet Bubbling When My Washer Drains?

      When our washing machine completes its final rinse, it will begin its draining process. 

      If we hear a gurgling sound from our bathroom, we may wonder, “why is our toilet bubbling when the washer drains?” 

      This sound may be slightly irritating but should be investigated immediately to avoid any more serious plumbing issues. 

      The first thing to diagnose is the drainage setup behind our washer. Water can easily leak from any untightened connections. 

      Our washing machine drain lines must be the recommended size, diameter, and length. If we use the wrong sized pipe, it can restrict the air from making it out of the drain line at all. 

      While it doesn’t require a licensed plumber to fix the washing machine’s drain line, it has to be correct. 

      Once we have diagnosed the drain lines, we can focus on what is most likely a blocked sewer line or vent stack. 

      All the plumbing in our home share pipes and vents to ultimately reach the main city sewer line or a septic tank. When anything in that line gets clogged or partially blogged, all sorts of issues can arise. 

      From slow drains to gurgling noises, we can usually take care of most minor plumbing issues by ourselves.

      Did you know? We can ask our neighbors if they are experiencing the same issue. This lets us know that the problem is in the city’s main sewer line.

      did you know why is my toilet bubbling

      Why Is My Toilet Bubbling After Flushing?

      When a toilet gets clogged, it doesn’t always overflow dramatically. Sometimes a slow drain is the first sign of something blocking the line. 

      The water seeps through the blockage forcing the negative air back up the pipe. This creates a bubbling sound inside our toilet bowl. 

      We can usually tackle the project ourselves, depending on where the clog is, without calling a plumber.

      Why Is My Toilet Bubbling When The Sink Is Running?

      Noticing our toilet bubbling when our sink is running shouldn’t be ignored. While wastewater and sewage need to be able to flow freely down the line, the negative air pressure also needs a place to vent itself. 

      The air will always find a way to escape. In this case, it found the toilet! The water from the sink creates a vacuum while flowing down the sewer line. 

      The negative air needs a place to vent and will always take the path of least resistance. If this air travels up our toilet, we know that it cannot get down its designated sewer pipe.

      Why Is My Toilet Bubbling With A Septic Tank?

      The drain lines from our home can lead to one of two places. Our house connects to the city’s sewer system or a septic tank in our yard. 

      With our septic tank full, it creates a bubbling noise in our toilet. This can happen from too many solids and waste unsuitable for a septic system, getting flushed down the lines. 

      The pipes that route the waste away from our house need maintenance regularly. When we have a septic tank system, we must check it often to ensure it functions properly

      The bubbling sound from our toilet could signal a clog in the drain line leading to our septic tank. As the wastewater makes its way down the pipe, the air is forced back up the vent stack. 

      A clogged septic tank vent pipe can be the culprit for a gurgling toilet. 

      Sewer gases gurgle out of our toilet water without any other redirection to go. Whether the vent stack or the sewer line is blocked, it needs clearing immediately.

      Why Is My Toilet Bubbling When It Rains?

      If we live in an older home, we might have a shared sewer system. This system allows the excess irrigation runoff and raw sewage to accumulate through the same pipes. 

      While newer construction prevents these issues, extreme downpours can cause these systems to back up. When this happens, we might see our toilet bubbling when it rains. 

      Another cause is when rainwater finds its way into our sewer lines. 

      From uncovered vent stacks to cracked pipes, this unwelcome water can be overbearing for our sewer system and will force the negative air pressure to escape wherever it can.

      How Do You Fix A Bubbling Toilet?

      A bubbling sound coming from our toilet is nothing that should we should ignore. It is usually a sign that we have an obstruction in the sewer line or vent pipe. 

      The first thing we can do is try to dislodge the blockage. If the bubbling only seems to be affecting the toilet, we might try our luck with a plunger

      With a handheld plumbing snake, we’ll be able to clear the line from other areas and hopefully resolve the bubbling noises in our toilet. 

      We will see the vent stacks on our roof. These are vertical pipes sticking straight out of our rooftop, usually covered with a mushroom-shaped shroud. These are other areas that can get blocked.

      Once a visual inspection is done and anything in the way removed, the gurgling sound from our toilet should stop. Anything backed up should rush down the pipe immediately when the clog is free.

      Toilet Bubbling FAQs

      Why is my toilet randomly bubbling

      When our sewer line gets clogged, air pockets build up around the blockage. When the water pressure behind the air increases, it is forced back up our toilets.

      Why does my toilet make a gurgling sound?

      We hear strange gurgling noises in our toilet when there is a blockage in the drain line. The negative air will travel the wrong way through the pipe and bubble out of the p-traps.

      Is it bad if your toilet bubbles?

      A bubbling toilet might not be too annoying at first. It is, however, a possible sign of a serious plumbing issue. It needs to be investigated immediately.

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      About Plumbing Navigator

      We write about "all things plumbing," helping you navigate common questions, repairs, and the best plumbing products on the market.

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      We write about “all things plumbing,” helping you navigate common questions, repairs, and the best plumbing products on the market.

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