Why Won’t My Toilet Stop Running?

A toilet that keeps running is never a pleasant experience. Not only does it get on your nerves, it can also drive your utilities bill up, and is certainly not good for the environment. A leaky toilet tank can also cause brown toilet water. 

Why a toilet keeps running is usually down either to a faulty flapper or an unaligned float, but there could be more to it than that. 

Let’s explore why your toilet is running for no apparent reason (and what a float and a flapper actually are). 

Why Won’t My Toilet Stop Running?

The most common reasons a toilet won’t stop running are a dirty or broken flapper, an out-of-position float, or the chain between the flush lever and the flapper might be too long or too short. 

The fill valve may also be the culprit, or there may be something wrong with the flush handle. The refill tube may also be too long and the reason your toilet keeps running. 

Parts of a Toilet Tank 

To help you better understand why your toilet won’t stop running, first identify the parts of the toilet, and what they do: 

1 – The flush lever is located on the outside of the toilet, and is connected to the flapper by a chain or arm. 

2 – The flapper is what stops the water from running from the tank to the bowl. When you turn or pull on the handle, the chain that connects them lifts the flapper, and your toilet flushes. 

3 – The pump refills the tank after each flush. 

4 – The float rises and falls with the water level, and it tells the pump when to stop. 

5 – The overflow tube determines where the water level should be. 

And now for the possible reasons your toilet won’t stop running: 

Dirty or Broken Flapper

The flapper will naturally get dirty over time, and it may also start to warp or break. When it doesn’t provide a good seal, your toilet won’t stop running. 

To test if this is the case, take the lid off your toilet tank, and push the flapper all the way down, but don’t move the handle. If this stops the water running, you have identified the cause of your running toilet. 

If the flapper seems in one piece but is merely dirty, clean it well and see if that helps. Drain the tank before removing the flapper. 

If you need to replace it, try to find a flapper made by the brand you already own. If you can’t find one, go for a universal flapper that looks like the one you already have. Note that you may have trouble finding a flapper that fits, especially if your toilet is old. You may need to replace the entire flapper system, which is better left to a professional plumber. 

After you have replaced the flapper, check once again if the seal is tight enough. 

Out-of-Position Float 

The float controls the water level in your tank. If it’s set too low it will result in a weak flush. If it’s set too high, water will keep spilling into the overflow tube and keep running into your toilet bowl. 

Turn off the water flow into the tank and take the lid off. Your tank should have a fill level mark on the back. Mark this height on your overflow tube. If you don’t see it, measure about an inch down on the overflow tube. 

Turn the water back on and flush the toilet to see where the water will stop relative to the mark you just made. If it goes over, the float is set too high, and vice versa. Adjust the float until you get it to the right level. 

Faulty Fill Valve 

The fill valve won’t shut off properly sometimes, and you will need to replace it (the fill valve is the thing the float is connected to). Fill valves are usually quite universal, so you shouldn’t have any trouble finding the right one. Take the one you have with you to the store, to make sure. 

Turn the water supply to the toilet off and drain the tank. Disconnect the water supply valve from the fill valve, and then remove the latter. Replace it with your new one, and reconnect the supply valve. Adjust the float. 

Turn the water back on and see if you’ve managed to fix the problem. If water is still running, you may need to call in some help. 

Too Short or Too Long Flapper Chain

A flapper chain that is not the right length may also be what’s causing the problem. 

First, check if the chain is connecting the flush lever (the part of the handle on the inside of the tank) and the flapper correctly. Sometimes it may just be disconnected. Then shake the lever to see if there is too much or too little slack in the chain itself. 

If it’s too short, water will keep running into the bowl because the flapper doesn’t provide the right seal. If it’s too long, the flapper won’t actually move when you flush. Adjust the chain to fit better, depending on the issue. 

Too Long Refill Tube 

You may also discover that your refill tube is continuously pumping water into the bowl, because it’s too long and not properly positioned in the overflow tube. 

In order to adjust it, pull it out of the overflow tube and hold it above the opening. Trim it and clip it to the side of the tube to keep it in place. 

If you are uncertain how this issue could be causing a toilet that won’t stop running, it’s because the refill valve creates a suction effect that pulls water out of the fill valve. That’s basic toilet tank mechanics for you. 

Faulty Toilet Flush Handle 

If your toilet handle is too loose and keeps wiggling all over the place, or if it’s hard to maneuver and keeps sticking, it’s time to replace it. 

Look for a handle that is as similar to the one you already have as possible, and make sure you reattach the flapper chain correctly. 

What To Do If Your Toilet Won’t Stop Running

If your toilet won’t stop running, start by turning off the water that supplies the tank. It’s usually a silver knob right next to or behind the tank. 

Then take off the lid of the tank and drain the water. Based on the potential causes of a running toilet outlined above, you may be able to identify a leaky flapper or a misplaced float. If however you have no idea why your toilet won’t stop running, your best course of action is to call in a plumber. 

In the meantime, you can keep turning the water supply on and off as you use the toilet, to prevent the water from continuously leaking. 

Wrapping It Up 

A toilet that won’t stop running is nothing unusual, and is usually an easy fix. Hopefully, you now understand how a toilet tank works, and are able to fix it yourself.