Air Bubbles in Toilet: Causes and Fixes

When you have air bubbles in your toilet, it can be a sign of a clog which could get worse if not fixed in time. The clogs can be anywhere from the toilet, the sewer line, and even the vent pipe as well. You can avoid a nasty sewer spill in your toilet with a few easy fixes. 

Bubbles in the toilet are due to negative air pressure from a clog either in the P-trap, sewer line or the vent stack. Unclog the toilet and sewer using a toilet plunger, auger or chemicals. Unclog the vent stack with water from a hose or a pole to poke the clog and fix air bubbles in the toilet.

Air Bubbles in Toilet

What causes a toilet to burble? 

Why does the toilet bubble? Having bubbles in the toilet means that there is negative pressure building up in the sewerage system. This negative pressure is almost always created by a clog which prevents the balance of air and pressure between the sewer line and the air outside. 

Some of the causes of toilet gurgling include the following:

A clog in the toilet

If your toilet is bubbling when flushed, chances are that there is a clog in it. This could be caused by something as simple as toilet paper, or some more serious problem like human waste from the sewer system backing up into your home’s plumbing.

The same is true when the toilet is bubbling and won’t flush. The clog in the toilet will be preventing air from leaving, and pressure is building up. That gurgling sound from the toilet is an indication that the clog is a major one and could cause more problems. If not fixed quickly, you may have the toilet gurgling more and water backing up owing to the clog. 

If the toilet gurgles at the end of flushing, it means that the clog in it is a small one as most of the wastes can pass through. If the toilet burps a big bubble when flushed, it’s a sign of a major clog either in the toilet or in the sewer line.

If the toilet flushes slow and gurgles, it’s a sign that the clog inside it is a big one which could cause problems. You’re better off dealing with a case where the toilet flushes but gurgles since the clog is much smaller in the latter case. 

A blockage in the sewer line

Your house has a drain line which is made up of the lines from various fixtures (toilets, sinks, shower drains) which lead to the mainline, and the mainline which collects all the water and sends it to the sewer. If you notice your toilet bubbling on its own, when the shower is running, or when the washer drains, it means that there is a clog in the sewer line affecting the drainage system in general. 

A clog in the sewer line can be caused by a number of things, but the most common culprits are solid wastes, grease, or you flushed something that shouldn’t have been (nail polish, paint). The clog can also be located at different sections of the home’s drainage system, and the bubbling will be happening at a different fixture. 

Tree roots, earthquakes, and even changes in the weather can also cause blockages in the sewer line. In some cases, the clog can be located in the municipal sewer line and the bubbles will be happening at your home’s sewer line. If your neighbors are also complaining of the clog or bubbles coming from their toilets, it’s probably a clog outdoors. 

A clog in the vent stack

The purpose of your vent stuck is to allow air to escape from the toilet. The vent stack is connected to all the toilets in the home and is located outside the building. 

A clog in a vent stack typically occurs from debris such as leaves, tree branches, birds’ nests, rodents, and even dead birds. A clogged vent stack often leads to air bubbles in the toilet bowl.

To check for a clog, take a peek into the vent stack using a flashlight tied to a long pole and lowered into the vent stack. 

A faulty cistern (toilet tank)

If you see any air bubbles in toilet tanks, chances are that it is because of a faulty cistern. This often happens with homes that are more than 20 years old, but even newer houses can suffer from this if the seal was not installed properly when they were built.

The culprit is usually a faulty flapper which doesn’t provide an airtight seal when the toilet isn’t being flushed. In some cases, the air bubbles in the toilet tank will be accompanied by the toilet flushing itself (ghost flush). 

How to fix a gurgling toilet 

Whether you’re dealing with a case of a gurgling sound when flushing the toilet or toilet bubbles when showering, the solutions are as follows:

Plunge the toilet

Seal all the drains in the home with duct tape then use a plunger on the toilet to unclog it. This is one of the simplest and most effective methods available.

Given that the plumbing system is connected in the home, sealing off the drains prevents the pressure from the plunger from escaping and instead focuses it on the clog in the toilet. 

If your toilet burbles when the tub drains even after using a plunger, try using chemicals to unclog the toilet as in the next fix. You can also unclog the toilet without a plunger if you don’t have one.

Use chemicals to unclog the toilet

Pour the chemicals into the toilet, wait for an hour then flush the toilet to do away with the clogs. 

One of the best ways to solve this issue is to use chemicals that unclog and break down blockages such as Draino. It may take time for these chemicals to work on larger obstructions but will eventually do so with enough contact. 

Each of the unclogging chemicals usually has its own instructions which need to be followed for the best results. 

If there is still a toilet burping after plunging and using chemicals, you can try snaking it as in the solution below. 

Snake the drain

Insert the flexible end of the toilet snake into the bubbling toilet bowl, push it in until you feel the clog then crank the handle to unclog the toilet. Flush the toilet afterward. 

A toilet snake, also called a toilet auger, plumber’s auger, or plumber’s snake, is a long, flexible metal or plastic tube that can be pushed into the toilet drain to remove clogs.

There are motorized toilet snakes that eat away at tougher clogs such as tree roots or tough balls of dirt in the toilet. For deeper clogs, you may need to remove the toilet seat to use the toilet auger. 

If, after using the toilet snake, there’s still a toilet gurgling after flushing, you may need to insert the toilet snake into the sewer cleanout located outdoors since the clog may be in the sewer line away from the house. 

Clear the shower drain

Remove any solid objects from the shower drain then pour in a cup of baking soda followed by a cup of white vinegar. After 15 minutes, flush the drain with hot water. 

Change the toilet flapper

Replace a toilet flapper in the following steps:

  1. Turn off the shutoff valve. 
  2. Empty the toilet tank by flushing the toilet.
  3. Remove the old flapper by removing the clips and chain holding it in place.
  4. Install the new flapper by clipping it into place and attaching the flapper chain. 
  5. Adjust the flapper chain to the right length. 
  6. Test the new flapper. 

Replacing the toilet flapper should stop bubbles from coming out of the toilet tank. Replace a faulty shutoff valve if the current one doesn’t stop the water to the toilet tank to make this process effective.

Clear the vent stack

Take a narrow flashlight, tie it to a strong narrow pole then lower it into the vent stack on your roof to check for a clog. If you see one, poke it with a stick or pour warm water into the vent stack to unclog it. 

Clogs in the vent stack can also occur on the pipe openings and condensation trap holes. These can be removed with pliers while you’re on the roof. 

At times, venting your toilets may be a problem hence the need for wet venting. Wet venting is venting the toilets and drains separately to eliminate over-reliance on the main venting pipes. 

Call the plumber

If you still have a toilet making gurgling noise after all the options above, call your plumber since it means that the problem is a bit more technical than these DIY solutions. 

You can also call your plumber if you can’t carry out any of the solutions explained here due to one reason or the other. 

Depending on the location of the clog, the plumber can be your own or one from the government. 

How to prevent the toilet from gurgling

You can prevent air bubbles in the toilet with the following measures:

  • Flush water from time to time in order for any debris stuck inside drains to go through. This will avoid clogs and air bubbles in toilet problems.
  • Furthermore, you can clean your pipes with vinegar or once every week as this helps prevent buildup too. Avoid using toilet bowl cleaners in the shower.
  • Avoid flushing feminine products, wet wipes, cigarette butts and any other insoluble items down the drain since these are the main causes of clogged toilets and sewer lines. 
  • Provide cover for your vent stack such that objects can’t get in but the sewer gas gets out.
  • You can also prevent toilet gurgling by cleaning your toilet bowl every week to prevent calcium and other mineral deposits which may lead to clogs.
  • You should have a plumber inspect your sewerage system occasionally to prevent any major issues from occurring. 

With these practices in place, you’re less likely to face a situation where your toilet is clogged and the toilet emits bubbles. 

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