Toilet Burps Big Bubble When Flushed? (Here's Why)

Ossiana Tepfenhart
by Ossiana Tepfenhart

Toilet problems are annoying, expensive, and almost unavoidable for the average homeowner. Some issues can be puzzling, such as a toilet that bubbles and gurgles when you flush it for no apparent reason. So, what does it mean if your toilet bubbles when flushed, and what should you do about it?

It typically means that there is negative air pressure in the drain line if your toilet bubbles when flushed. Suction in your drain line or vent stack can cause your toilet to gurgle and the extra pressure makes the water bubble. Toilets primarily bubble when there is a clog in the drain line, but it can also happen if your septic tank is full.

The average homeowner can fix a bubbling and gurgling toilet, but professional help is necessary in some cases. Problems with a septic tank or vent stack often require professional help because of the difficulty and danger involved. Follow along as we explore what it means when your toilet bubbles when flushed.

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Why Does My Toilet Gurgle?

Toilets generally gurgle if there is an airlock caused by suction in the drain line. The suction in a drain line can create excess pressure and cause the toilet to bubble when you flush it. A toilet can also gurgle if the sewer vent or septic tank is full and clogged.

It is important to fix the toilet if it bubbles when flushed before the problem gets worse. You can only fix a gurgling toilet if you diagnose the problem. Let’s take a look at how you can troubleshoot and fix a toilet that bubbles based on what the problem is.

How to Fix a Toilet That Bubbles

1. Plunge Toilet

You can generally stop your toilet from bubbling when it flushes if you plunge it. This works if your drain line is clogged, and the plunger can help loosen the obstruction. Plungers create suction that can help break up a clog or an airlock altogether.

The most effective way to stop your toilet from gurgling when the line is drained is to tape over the sink and shower drains before you plunge the toilet. You tape over the other drains to concentrate the pressure and remove the clog. Remove the tape from the shower and sink drains, flush the toilet, and check to see if it still bubbles.

If the toilet still bubbles, then it is likely that there is a clog deep in the drain that your plunger couldn’t break up.

2. Snake the Toilet Drain

Homeowners can use a drain snake as an alternative to a plunger, but it is ideal to use them together. Break up the clog with a plunger and go in with a drain snake to remove all obstructions and clean the line. You can snake a drain even if you don’t plunge it first, but it may be more difficult and less effective.

Be careful if you snake the drain without plunging it first because it is possible for part of a drain snake to break off in the drain line. It is possible to get a broken snake out of a drainpipe, but it’s best to reduce the risk and plunge the toilet first. A 15-foot drain snake should be enough to clear your drain so that it doesn’t bubble or gurgle when you flush the toilet.

3. Clean Vent Stack

The sewer vent stack on your roof is exposed to plenty of debris and it can clog. A clogged vent stack can cause an airlock in your sewer line. Inspect your vent stack for debris and look for debris that blocks the vent.

It is important to exercise caution and pay attention to your roof’s pitch when you clean a vent stack. You can use a drain snake or even a garden hose to remove debris that is deep within a vent stack. Otherwise, you can clean your vent stack from the inside of your home with a drain snake if you have an attic.

4. Unclog Septic Tank

It can be messy work, but you may need to unclog your septic tank if your toilet bubbles when you flush it. Put on gloves and protective face gear, open the closest septic tank access lid and inspect it for clogs. Clear waste away from the inlet pipe with a long pole and push it to the side so away from the top of the pipe.

Stick the end of the pole into the inlet pipe and pull waste out of it. You may need to repeat this process several times until water can properly flow again. However, it may not be possible to access your septic tank or even reach the clog for all homeowners.

5. Call a Plumber

Call a plumber if you have tried several fixes without any success. There are sanitary hazards when it comes to working with septic tanks in particular, and plumbers are equipped to handle them. It is also dangerous to work with the vent stack on your roof if you aren’t experienced or comfortable with working on a roof.

What Happens If You Ignore A Belching Toilet?

There are a lot of things that can happen if you let a burping toilet sit, none of which are particularly pleasant to deal with. If your toilet and other appliances share a drain, then you might see your waste back up through the sink and shower drains. Other times, the clog that is stuck in your septic tank line may cause slow draining throughout the home.

The worst thing that can happen is that that suction gets to be too powerful, to the point that a burst occurs in the pipes. This can render your plumbing system useless, cause a bunch of damage in the form of spilled sewage, and also harm your home via mold. Since renters insurance and homeowners insurance doesn’t cover mold, this could put you in a bad position.

How Much Does it Cost to Fix a Gurgling Toilet?

It costs an average of $350 to fix a gurgling toilet if you hire a professional, but it can cost as little as $100. You can fix a toilet that bubbles when you flush it if there is a simple clog in the drain line and you already have a plunger. However, severe clogs are expensive and it can cost as much as it does to hire a plumber if you have to buy special tools.

It costs an average of $300 to buy an auger, and that can sometimes be more expensive than hiring a plumber. You may have to spend $370 or more if you need to unclog your septic tank, and that is best done by professionals. Clogged vents are inexpensive to take care of, and professionals charge $100 on average for simple clogs.

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Related Questions

How do you fix an airlock in a sewer line?

If you have an airlock occurring in your sewer line, you can fix it pretty easily. Start by turning on your hot water tap and letting it run for a minute or two. Then, slowly turn on the cold water tap. When the cold water gets pushed out, the air lock gets pushed out too.If you have a water line that mixes the hot and cold water together, then place a rag over the spot and twist the cold tap on. This will force the water back in but let the air belch out.

Do airlocks usually happen in water systems?

Airlocks are common, but don’t panic. Truth be told, airlocks aren’t actually supposed to be that big a deal. Most of the time, a well-designed water system setup will be able to take care of them and even help the airlocks go away on their own. This is why you might not even notice an airlock in your system.The only time that airlocks become a big problem is when you have a poorly designed system. If you notice regular problems with airlocks, call a plumber to see if you need a replacement pipe or toilet.

Can a toilet get airlocked?

Believe it or not, yes. That’s what you’re hearing when you hear a toilet that is gurgling on its own. The negative suction that the toilet is experiencing is caused primarily by an airlock that needs to be addressed. In most cases, this is indicative of a clog that is either in the toilet’s stream, in the septic line, or in the sewer vent up by the roof of the house.

Summing It Up

Cover your sink and shower drain and plunge the toilet if it bubbles when you flush it. Use a drain snake if there is still debris deep within the sink drain. Inspect the vent stack on your roof for debris and clean it with a drain snake or garden hose.

Your septic tank may be clogged and you will need to clean it if your toilet continues to bubble. Hire a professional if you cannot access your septic tank or don’t have a sanitary way to clean it.

Ossiana Tepfenhart
Ossiana Tepfenhart

Ossiana Tepfenhart is an expert writer, focusing on interior design and general home tips. Writing is her life, and it's what she does best. Her interests include art and real estate investments.

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