Why Does My Toilet Overflow? How Do I Fix It?

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Last Updated on August 26, 2022 by acechapman

A leaking toilet can be the worst nightmare of your life. So, what do you mean by “why does my toilet overflow?”

Well, you can’t solve your problem right away, though. An overflowing toilet can become a dangerous situation if you don’t take action quickly.

Overflowing a toilet is more common from a bowl than from a tank. So what’s your case?

Toilet overflowing can be caused by a problem with the vent pipe, something stuck in the toilet sewage pipe, a high-filler float, a broken tank float mechanism, as well as a clogged toilet.

If the toilet is leaking from the tank, it is most likely that the overflow tube is broken or that the flapper is malfunctioning.

Is the water overflowing dirty or clean?

You will need to call a plumber depending on the water quality. If you have any questions about wastewater, call your plumber immediately, and don’t waste your time. It’ll be too much to handle otherwise.

toilet and washing machine

What are the causes of the toilet bowl overflowing?

In the United States, Uk, as well as Canada, the most common plumbing problem is an overflowing toilet. These are the top trends.

The Vent Pipe

Yes, a toilet can overflow if it is blocked by the venting pipe. Vent pipes are used to move air through the toilet and regulate the pressure.

If the vent pipe becomes blocked or jammed, the air cannot escape and therefore, will not move in the backward direction to your toilet.

The bowl is flooded with water, so the drain moves towards the bowl. This is what causes the drain to overflow and stabilize the air.

You may sometimes hear a bubbling sound. Unwanted odors or bubbling sounds after flushing the toilet can be caused by a blocked vent.

The direct answer to your question “Why is my toilet overflowing and bubbling? It is because of a blocked venting pipe.

In this case, you may call a plumber.

Clogged Toilet Bowl

Toilet overflows can also be caused by a blocked or clogged bowl. If an object gets stuck in the toilet bowl, it can block water from draining. When you flush, the water will overflow.

You can use a toilet auger instead to clear the duct or you can try these proven methods.

Sewage Pipe Issues

Are you aware that the sewer pipe in your house can be sensitive? The sewer pipe is responsible for everything you flush down, from your kitchen sink to your toilet as well as the bathtub.

Too much toilet paper can build up and can also cause a blockage in the pipe. These piles are difficult to pass through.

A sewage pipe blockage could lead to a leaky and overflowing toilet.

If the sewer is unable to drain properly, it will return up your line and enter your apartment through the lowest level.

Faulty Sewer Pipe

Imagine that you have shut off the main water supply to your house, but still, the toilet overflows and floods again. The problem is with the sewer channel that runs nearby and connects to your main house.

Contact your local sewer department to request an inspection of your system.

Broken Tank Or Flush Handle

A broken handle or tank could also be a possible cause of the toilet not draining properly.

If the toilet’s flush mechanism breaks, it will flush without anyone’s assistance. Thus, resulting in a running water toilet.

Broken or malfunctioning handles are another possibility. Slowly flush the water into the bowl – continuous flushing is the reason for flooding and running the toilet.

You can change the handle and go without running water instead.

Septic Tank Issues

You may experience the same problem if you own your septic tank. There are several possible reasons.

1. If the septic tank gets full

2. Incorrect working in the septic tanks

3. The septic tank drain is blocked.

Any plumbing service can inspect the septic tank.

Slow Flushing Toilet

Toilet water overflow can be caused by a slow flushing toilet. Low flush pressure can cause clogs or blockages. Thus, preventing the material from being flushed away completely.

Excessive water can cause flooding if it is left unattended.

Use a Pressure Assist Toilet instead to avoid slow flushing.

Slow flushing with the broken flush mechanism would also cause a toilet to overflow when flushed.

why does my toilet overflow

Overflowing From The Tank

You can repair the toilet by yourself if it overflows from the tank for very few reasons.

Broken Overflow Tube

Broken overflow tubes can cause run-over water in the tank.

The main component of the flush valve is the overflow tube. The overflow tube prevents water from overflowing in the fill tank.

If the overflow tube is having an issue such as-

  • Leakage
  • Too high in relation to the tank
  • The overflow tube does not allow the float ball to adjust.

These could be the reason for the toilet not draining completely from the tank.

Adjust the overflow tube to stop the toilet water tank from flooding.

Toilet Float Ball

The toilet float ball, also known as the Bobber (you can see a ball or balloon in the tank), is used to help water fill the tank.

The toilet float ball usually lifts with the water level. Thus, allowing more water to drain down into the overflow tube.

The scenario shows that Bobber is not working well and cannot rise with the water level. As a result, the tank overflows.

This problem can be solved by adjusting the height of either the ballcock cup or the float cup.

How To Fix An Overflowing Toilet?

Toilet overflowing can be a disaster. This situation can be prevented by taking immediate action.


  • Look at the guide to find the source.
  • If water is leaking from the tank, it’s okay to change and adjust the valves.
  • If the water is not draining from the bowl, it can be a sign of a leaky faucet. Then, verify the water speed, smell, color, and temperature.
  • When the vent pipe is causing smelly toilet water. Get help from an expert.
  • No smell or damage to the tank. Replace the tank with a clean one.
  • If you smell musty and dirty, call an expert immediately.
  • The following proven methods can be used to blockage a drain
  • All water supply lines connecting to the toilet overflowing should be cut off.

Frequently Asked Questions

Can a toilet overflow without being clogged?

Yes. Toilets can overflow even if they are not clogged.

  • Defective flush mechanism
  • Faulty overflow tube
  • Septic tank problem
  • Slow flushing toilet

How do you unclog an overflowing toilet without a plunger?

You can unclog a toilet with a toilet snake, or an auger, without the need for a plunger.

Can Toilets Overflow on Their Own?

Yes, toilets can overflow on their own when the flushing mechanism fails.

Wrapping Up

If you don’t act immediately, an overflowing toilet can become a terrifying situation.

These are some suggestions to keep your toilet from overflowing in the future.

  • Make sure that only human waste and toilet paper are flushed down your toilet.
  • Avoid flushing plastic objects. It is best to immediately retrieve any items that have been accidentally flushed.
  • Avoid flushing condoms, tampons, as well as food waste.
  • Also, do not throw out Q-tips or baby diapers.

It is usually best to call a licensed plumber if in any case, the problem becomes worse.

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