Toilet bubbles aren't just odd they can signal bigger plumbing trouble that puts your whole home at risk. When toilet bubbles appear after a flush, it usually means air is backing up in the drain line, and if left unchecked, you could face messy overflows in your tubs, showers, and sinks. Our go-to trenchless repair method often stops bubbling at the source by clearing stubborn blockages without tearing up your yard or floors. Read on to discover five common causes of toilet bubbles, step-by-step fixes you can try today, and expert tips for preventing future gurgles. With these straightforward solutions, you'll save time, avoid costly damage, and keep your plumbing running smoothly.

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Why your toilet bubbles and how can it become a major problem?

Don't be afraid! If your toilet begins to bubble or gurgle, it means that there is abnormal suction building up in the line, causing air to push back, create

Reasons Toilets Bubble

 bubbles, and even cause the toilet to flush.
But you've heard the warning signs, and can now take the proper steps to correct it.
If left alone, toilet bubbling can lead to unwanted waste overflowing your toilets, showers, and tubs, creating even larger nastier issues. Below is how to find the root of the problem, the necessary steps to fix it, and how we can help at New Flow Plumbing.

After flushing, toilet bubbling can occur due to clogging.

5 Common issues and how to fix them!

Here is how to identify where the source of the problem is located, and how to fix each one. Some may require professional help, but others can be done right from home with your very own skills.

1. A clogged toilet

We are all too familiar when something that's not supposed to be flushed… gets flushed. Paper towels, tissues, feminine products, cigarette butts, and "flushable" wipes, are usually the main culprits. In this case, the plunger and sewer snake are your go-to tools.

Reasons Toilets Bubble

If the clog is close to the surface, a plunger should clear it out.

Solution:

Seal off any other fixtures in the bathroom (tub, sink, shower,) with duct tape before plunging the toilet. This will keep pressure from escaping and allow it to clear the drain line.
If the clog is close to the surface, 10 to 15 firm pumping motions should remove it.

If the plunger doesn't do the job, a manual or mechanized sewer snake (or plumber's auger), should clear out the harder to reach and tougher clogs.

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2. A faulty cistern

Inside the cistern, the flapper is responsible for flushing and refilling the tank with clean water.
Check to see if the flapper is damaged or faulty, and is preventing water to properly drain.

Reasons Toilets Bubble

Dirty flush toilet mechanism in restroom

Solution:

If the flapper is defective, changing it out for a brand new one should clear the issue up. If the problem is the entire cistern mechanism, then the whole cistern will need to be replaced.

3. A blocked vent stack

The vent stack is a vertical pipe leading to your roof that helps control your plumbing air pressure and releases exhaust gas. It is not supposed to be sealed, closed, or blocked, which will lead to reverse suction and cause bubbling.
Another sign the vent may be the issue is a gassy odor smell leaking into the house.

Reasons Toilets Bubble

Chimneys on a building rooftop against a blue sky.

Solution:

The most usual vent blockage comes from birds building nests. Other small animals or leaves may build up in the vent, and prevent it from doing its job.
Note: Since the pipe is on the roof, take caution when attempting to clear out any debris from the vent.

If the vent is unreachable or the clog is not near the surface, New Flow Plumbing is more than happy to help. Reach out for home plumbing issues here.

4. A clogged mainline (contact us!)

The mainline leads all the wastewater from your home's fixtures to your city connection. If the clog affects your entire house, such as a one toilet flushing causes another to bubble, then the issue is likely the main.
Reasons Toilets Bubble

The mainline can be the cause of toilet bubbling.

Solution:

The mainline is more difficult to access and used to be very expensive to fix if damaged. Not anymore!
New Flow Plumbing offers trenchless sewer repair which is a time-saving, cost-effective, and lasting solution.
The traditional repair involves tearing and ripping out floors, walls, and dirt from your yard which will cost you more money. With trenchless, we solve the issue without tearing up your house.
Trenchless sewer repair uses very little digging. Just two, 4ft by 4ft pits to gain access to the pipe. Traditional sewer repair that used to take days now takes only hours. When New Flow Plumbing is done, you don't need to break the bank trying to repair the damage left behind.
Note: Sometimes a sewer pipe is so badly damaged that no trenchless repair method is usable.

When it's impossible to use a trenchless repair method, we use conventional sewer replacement methods. Nonetheless, contact us and we can find the solution that works for you.

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5. Clogged or damaged city connection

In this case, the source of the problem is out of your hands and now falls into your utility company or city municipal department. If your entire house is affected, ask your neighbors if they are having similar problems. If so, check your water provider and report the issue promptly.
If attempting to resolve the issues on your own doesn't seem to work and the bubbling continues, call us at (310) 861-3463
New Flow Plumbing can perform a CCTV sewer inspection that can locate precise clogs in your pipes, and snake them out. We can easily solve your problems and make life that much easier!

FAQs

Shower bubbling during a toilet flush happens when a partial clog or vent blockage forces air to escape through the shower drain. As water rushes past the obstruction, it pushes trapped air back up, creating bubbles.

Yes. A blocked vent stack prevents proper air exchange in your plumbing, creating negative pressure that can siphon trap water and allow sewer gases to leak into your home, causing foul odors.

Plunging often clears shallow clogs near the trap and stops most gurgling. However, if the issue lies deeper in the mainline or a vent is blocked, you may need a sewer snake or professional service.

Inspect your vent stack at least once a year, ideally before foliage season or storms. Clearing nests, leaves, or ice buildup ensures proper venting and prevents bubbling, slow drains, and odors.

Trenchless sewer repair replaces or relines damaged pipes through two small access points, avoiding extensive digging. It restores full flow quickly, preserves landscaping, and minimizes disruption.

Call a plumber if plunging and snaking don't stop the bubbling or if multiple fixtures gurgle with each flush. Persistent bubbling often signals a mainline clog or vent issue needing professional tools.

Arman Personal Passport Size Image

Arman Grigoryan

Founder & President of New Flow Pumbing

Arman Grigoryan is the founder and president of New Flow Plumbing, proudly serving Los Angeles, Sacramento, and surrounding areas. With extensive experience in plumbing diagnostics, he leads a skilled team specializing in advanced sewer and drain camera inspections to quickly identify problems and deliver lasting solutions. Arman is dedicated to using the latest technology to provide reliable service, honest answers, and dependable results for every customer.

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