What Causes a Toilet to Run

One of the most common reasons why a toilet decides to run is because there is a potential malfunction in one of its components. Although toilets are fairly simple in terms of technology, there are certain seals or rods that can change over time and prevent proper functionality.

A bad flapper, a bent float arm, or a crack in the flow pipe can all be causes of a toilet running, especially if it happens on a regular basis.

Sometimes, a toilet will only run intermittently. It may cut on and off at random times. When this occurs, it is often referred to as “phantom flushing.” This problem is caused by a leak that occurs from the tank of the toilet into the bowl. When water levels in the tank reach a low enough level, the toilet refills itself.

Here is what you’ll want to check on the problem.

When Was the Last Time the Tank Was Cleaned?

A flapper doesn’t have to go bad for it to begin malfunctioning. Mold or mildew can grow on the flapper seat and this can cause the flapper to not sit properly, creating the run. Homes with hard water may experience scale build-up within the tank and on the flapper seat, causing this problem. Cleaning the mechanisms within the tank can go a long way toward restoring its functionality.

Replace it, however, if it looks damaged.

One of the most common reasons why a toilet decides to run is because there is a potential malfunction in one of its components. Although toilets are fairly simple in terms of technology, there are certain seals or rods that can change over time and prevent proper functionality.

A bad flapper, a bent float arm, or a crack in the flow pipe can all be causes of a toilet running, especially if it happens on a regular basis.

Sometimes, a toilet will only run intermittently. It may cut on and off at random times. When this occurs, it is often referred to as “phantom flushing.” This problem is caused by a leak that occurs from the tank of the toilet into the bowl. When water levels in the tank reach a low enough level, the toilet refills itself.

Here is what you’ll want to check on the problem.

When Was the Last Time the Tank Was Cleaned?

A flapper doesn’t have to go bad for it to begin malfunctioning. Mold or mildew can grow on the flapper seat and this can cause the flapper to not sit properly, creating the run. Homes with hard water may experience scale build-up within the tank and on the flapper seat, causing this problem. Cleaning the mechanisms within the tank can go a long way toward restoring its functionality.

Replace it, however, if it looks damaged.

Is There a Trickling Sound?

If you have a slow trickle into the toilet bowl, then your supply line might be at fault. This problem is even more likely if a hissing sound is present when the toilet is running. It is an indication that the inlet valve has been compromised. You may be able to adjust the float arm to stop this issue, but you may also need to check the positioning of the refill tube.

You may also need to replace the entire assembly.

Do You Have Evidence of a Leak?

There are 5 common places where a toilet may leak and this can be the cause of the toilet running. Check the mounting bolts to see if they have become loose. You may also need to check on the seal between the tank and the toilet. The base of the ballcock in the toilet can also cause a problem.

There is also a wax seal underneath the toilet within the base. Look for evidence of moisture around the base of the toilet if you can’t find evidence of a leak anywhere else. Should you find it, then there is a good chance that you have a broken flange and will likely need the help of a professional.

By knowing what causes a toilet to run, you can quickly identify the problem being experienced and fix it. Running toilets can waste hundreds of gallons of water in a single month. Because these fixes are cost-effect and easy in most circumstances, it makes sense to start this repair project today.

Skip to content