Why Does My Toilet Randomly Run for a Few Seconds?

Why Does My Toilet Randomly Run for a Few Seconds?

Toilets are not supposed to run on their own. But what if you hear your toilet running for a few seconds in the middle of the night? Does that mean somebody just used the toilet and flushed it? Before you get scared, it’s best to learn more about this phenomenon. Maybe no one is on your toilet set and there is a good explanation for this.

Plumbers refer to this phenomenon as the phantom flush. So no, it isn’t caused by spirits or anything like that. There are several reasons why phantom flushing happens and having a ghost in your house isn’t the reason. So, don’t worry now. There’s nobody sitting on your toilet seat.

So that you won’t always ask, “why does my toilet randomly run for a few seconds,” and not worry about your increased water bill, here are the different reasons why this plumbing problem happens:


1. Cracked Toilet Flapper

toilet tank flapper

The toilet flapper’s job is to seal the tank, so water won’t get into the bowl when it is lowered. It follows that when the flapper is raised, water is allowed to get into the bowl. There’s a high chance that the toilet will randomly run on and off for several seconds if the toilet flapper is faulty or broken.

A decaying or cracked flapper allows water to keep flowing. It would mean that the toilet would run periodically. At any point the toilet tank runs out of water due to the broken flapper, the tank will refill. That’s why you hear water running randomly throughout the day or night.

2. Faulty Chain

lift chain

If after inspecting the toilet flapper you are sure that it was not broken or cracked, then the next thing to check is the chain. Is the chain that is connected to the toilet flapper faulty? If it is, then that could be the one that is causing the issue.

Notice that this chain pulls the flapper. It means that the chain controls the water to flow freely into the bowl. Any issue with the chain could affect normal water flow. For example, if the chain is shorter than usual, then the flapper could lift. In that case, water will flow right into the toilet bowl.

In case the chain is too long, it may get entangled or caught in the flapper, causing an improper seal. Without a good seal, the water can flow through the bowl, emptying the tank. When the water inside the tank is critically low, your toilet will randomly run for a few seconds, making it the exact cause of the problem.

3. Sediment Build Up

sediment build up

If sediment builds up on the toilet flapper, then you can expect that there won’t be a proper seal either. It may seem that the flapper seals the tank to keep the water from flowing through, but it doesn’t because of the presence of sediments. Even the tiniest amount of sediment could break the seal and allow water to run through. As a result, the water level becomes lower and there’s a need to refill the tank.

4. Out-of-place Flapper Valve

out of place flapper valve

Sometimes, there is no physical damage observed on the flapper, but it seems out of place. If this is the case, it’s necessary that the flapper’s position is recalibrated. Find the reason why the flapper fails to seal the water tank as water escapes from it. Be sure to fix it once you see the cause of the problem. The idea is to keep the water supply at an optimal level inside the tank so phantom flushing won’t happen at all. Don’t forget to check the flapper valve as well, while you’re at it.

5. Toilet Float Set Too High

the float cup

The main reason why a toilet randomly runs for a few seconds is that water flows into the bowl. A toilet ball float that is set too high may contribute to this issue as well. Setting the float too high will cause the water to get filled up and then poured over toward the overflow tube. To fix this issue, simply lower the toilet float and observe the overflow pipe. Replace any part that seems faulty.

6. Refill Tube Issues

Refill Tube Issues

The problem with the toilet running randomly may also be caused by refill tube issues. An improperly positioned fill tube will suck the water from the refill valve and send it to the toilet. The same also happens if the refill tube isn’t positioned correctly. So, don’t forget to check the refill tube when trying to fix the issue.

7. Broken Fill Valve

How to Fix the Fill Valve

Aside from the refill tube, another part worth checking is the toilet fill valve. Fill valves control how much water will fill up the toilet tank. If the fill valve is broken, then there is likely a water leak. It means water will just constantly flow into the toilet tank, never filling it up. A broken fill valve may also cause an uncontrollable toilet to run.

8. Toilet Flush Valve Assembly Problems

toilet flush valve assembly problems

Check the entire toilet flush valve assembly to see if there are problems with it. Anything broken in the flush valve assembly should either be fixed or replaced. In certain cases, there may also be the need to adjust the flush lever and assembly, so it won’t cause water to leak. You don’t want to be reminded how difficult it can be to fix a toilet leak so make sure you address this issue right away.  

10. Damaged Toilet Handle

drain toilet

The flush handle has a lot to do with this plumbing problem as well. If the flush handle is damaged, then it may allow some water to flow through. Either that, or it doesn’t go back to its proper place after flushing. Either way, it is contributing to the problem.

Consider replacing the entire assembly if this is the case. If you have a dual flush toilet, you must inspect both and make sure all are working well. Damaged flush handles are also a common cause of the running toilet issue.

11. Weak gasket

toilet tank to bowl gasket

There’s a gasket found at the tank’s bottom. The gasket is the one responsible for allowing the water to get out of the tank. It also subdues the flow of water after pressing the flush. If the gasket is weak, then the water will just pass through the tank and into the bowl.

When the tank runs out of water, then it will refill, causing the phantom flush phenomenon. To fix this problem, you’ll have to do more than just lift the toilet tank lid to inspect. You will need to remove many parts to get to the gasket and address that unnecessary water flow.

The gasket, while it doesn’t easily get broken, could get weak over time. It pays to have it checked as well if the rest of the parts listed above have been checked and the problem persists. If the gasket is broken, then you need to have it replaced.

12. Malfunctioning sensor

Some toilets no longer have flush handles. Instead, they have automatic sensors. Find out if the sensor of your toilet is still working as designed. It is possible that it is triggering the flush even if it doesn’t have any reason to. If the sensor is malfunctioning, have it replaced by a knowledgeable plumber. Just be extra careful in checking if you’re using one of those dual flush toilets.

Why Get Quality Plumbing Service

These are all the common reasons why you’re experiencing the phantom flush issue. Try to fix all these parts and your plumbing problem will disappear. If you need help with troubleshooting the issue, you can always contact a seasoned plumber to help you out.

Finding the cause of the problem is just the first step. The next and most important step is to find a resolution to the issue. While it is possible that the problem has an easy fix, it is still important that you continue to monitor the problem, so it won’t happen again. Otherwise, you’ll just keep on troubleshooting the same issue over and over.

Any good plumbing service will help you with this issue and a host of others, including drain cleaning and water heater repair, if you experience those too. They will also say if there is low or high water pressure, which is the one that is causing the problem, and they will provide a solution for that as well. After that, even water damage issues won’t scare you anymore!

So, if you need toilet repair or any type of plumbing service, don’t hesitate to call the pros. They can work with anything, from a water hammer to a water pipe.  With their help, you no longer must ask the question, “Why does my toilet randomly run for a few seconds?” Instead, you will have the answer and the fix for it. It also means that you don’t have to worry about a running toilet too. Your water bill won’t shoot up to the roof either.

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