Why Does The Toilet Flush By Itself? [Troubleshoot Like A Plumbing God]

If you struggle with a toilet that flushes by itself, the chances are that you are looking to fix this problem. Not only is a self-flushing toilet a huge waste of water and money, but you could face supplemental damage in your plumbing, messes in your bathroom, and more.

So, why does the toilet flush by itself?

In most cases, a “ghost flush” or “phantom flush” is a result of a leak in your toilet. This could be from:

  • A leaky flapper valve
  • A leaky fill valve
  • Something else

A toilet may flush by itself if the tank is too full of water or the flapper valve malfunctions.

Continue reading to learn more about why the toilet flushes by itself. This can be a costly, inconvenient circumstance to have to deal with, so you want to make sure you take care of the problem as quickly and efficiently as possible.

A faulty toilet is one plumbing fixture that you are definitely not going to want out of service for too long.

Why Does The Toilet Flush By Itself?

If your toilet flushes by itself, this could be for several reasons (Link).

Make sure you observe your toilet to take note of what could be the problem:

  • Interior plumbing problem
  • Leaky fill valve
  • Leaky flapper valve
  • Miscellaneous leaks
  • Structural damage

The Most Common Culprits

A leaky flapper valve, or flush valve seal, is one of the most common sources of a toilet that flushes by itself. When you flush your toilet from the outside, the handle you pull is connected to a chain or lever that lifts up, allowing water from the tank to rush into the toilet bowl and flush out the water. After flushing, the flapper valve closes and seals the hole connecting the tank to the bowl.

If the flapper valve somehow becomes damaged or the chain or lever attached to the handle disconnects, you are probably going to face some trouble with leaking. While it is not always a given that your toilet will flush by itself, a leaky flapper valve will at least continuously let water from the tank into the bowl.

This can waste several gallons of water per day.

Your toilet also might have a problem with a leaky fill valve. Technically, a leaky fill valve will not cause ghost flushing on its own. With a leaky fill valve, your toilet takes more water into its tank from the plumbing in the walls than it needs to. The tank of the toilet has an overflow tube that takes in excess water. When this happens, you can be wasting just as much water as with ghost flushes.

However, there is a small chance you may have ghost flushes with a leaky fill valve. Sometimes, if the toilet tank fills with too much water, it will rush into that overflow tube we just discussed. Whether this happens or not, some toilets can gauge when their tank has too much water, so they may do a phantom flush to keep the tank from overflowing. Thus, you will have a related problem with a leaky flapper valve.

The scenarios above are probably the most common reasons why the toilet flushes by itself, though other situations have been known to happen.

These Problems Are Not As Common But Are Serious

You might also have an interior plumbing problem within your walls. If something goes wrong with your plumbing, it can cause too much water to be pushed into your toilet, making it flush by itself to clear out excess water. Of course, typically, you will notice the source of the problem within the toilet, but it could be from something unseen in your main plumbing lines.

Your toilet might flush from basic structural damage. Especially with more modern toilets, it might flush to try fixing the problem. That is not to suggest that a toilet consciously knows when something is not right, but even for a leak that may not deal with the flushing system, your toilet might repeatedly flush.

Other miscellaneous causes of a toilet that flushes by itself may need to be looked at by a professional.

While most of the reasons listed above are probably the best places to start in observing what is wrong with your toilet, you may not find the source of your problem there.

Maybe the leak is simply too small, or maybe there is another reason you had not thought of. Either way, engage the services of a plumber if you cannot figure out the problem.

How Do I Stop My Toilet From Ghost Flushing?

If your toilet has started ghost flushing, there are a few things to consider doing.

If it is something you know how to fix or have dealt with before, it should not be a problem. On the other hand, if you are unfamiliar with any type of plumbing, you might want to think about getting a professional to help you fix your problem.

So, how do you stop your toilet from ghost flushing?

Test The Toilet For Leaks

Before diving into figuring out how to stop your toilet from ghost flushing, it is a good idea to try to find the source of the problem.

One of the easiest ways to determine whether you have a leak, be it in your flapper valve, fill valve, or anything else, is by putting a few drops of food coloring in the tank of your toilet.

After about fifteen minutes, check your toilet bowl. If the water is colored, you can be certain that there is a broken seal somewhere in your toilet.

Can I DIY It?

For something like checking a leak, you should have no problem doing it on your own. However, what about when it comes to fixing the leak?

Well, if you have even just a little experience with toilets, replacing the flapper valve or lever should be no problem at all. Still, any interior or structural work may require the help of a professional.

Call A Plumber

If you face a problem that you do not know how to fix- or you fail to locate the source of a problem – you should call a plumber. The chances are they will be able to locate the problem in minutes and get to work quickly on fixing your ghost-flushing toilet.

Look To Fix Your Toilet, Not Replace It

Toilets are not the most expensive fixtures you may have in your home, but they can still be a nuisance to replace completely. Instead of giving up and buying a new toilet, try your best to fix the one problem with your toilet or get someone with experience to do it for you. Typically, a toilet that ghost flushes has a quick fix that does not require an entirely new toilet.


In most cases, a toilet that flushes by itself has a leak in some part of the tank. Whether it be from the pipes leading to the tank or the tank leading to the bowl, it is not always a difficult fix. However, if you are not sure where the source of the problem is, it is best to contact a plumber.



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