How to Stop a Running Toilet

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It is not uncommon to come across a toilet that is constantly running. However, it is essential to ensure that water is not wasted. Besides, running toilets can be a nuisance in the house. The good news is that it is relatively easy to address the issue.

So, before learning about how to stop a running toilet, here is a discussion on how the toilet works first.


How The Toilet Tank Works

You need to have some basic understanding of the toilet's mechanisms before you embark on any repairs. What is the float ball, float cup, flush valve, fill tube, and flush rod? How do all of these play a tole in a running toilet.

Let's start with the handle. When you press the handle, there is a chain in the toilet that lifts a flap.

This flap is called a flush valve flapper, and it allows the water in the tank to move to the bowl. But as the water in the tank empties, the flapper starts to drop. It then closes the opening and waits for the water to refill in the tank.

Also, as the water is flowing out of the tank, a large plastic float arm drops. This toilet float is connected to a float valve that closes when the toilet has a full tank and the float is up and opens when the float is down and the tank is empty.

At the tank's center is a toilet overflow tube that drains any excess water from the water supply line into the toilet bowl. Therefore, if the water level in the tank is too high, the overflow tube ensures that the excess water is drained out.

Another function of the toilet overflow tube is to allow the float valve to release water into the toilet bowl during the refill and normal flush cycle. That said, if you constantly experience a running toilet, then several factors might be causing the problem.

Some of these issues include a water-logged float, a faulty flapper, or a high water level. If none of these issues is the problem, you'll have no option but to replace the toilet. It is important to get to know the float ball, float cup, and toilet overflow tube to figure out what is causing your running toilet. Otherwise, here are steps you should take to stop water from constantly running in your toilet.


Special Tools For Stopping A Running Toilet

To stop your toilet from running, you will need some pliers, cutting pliers, and rubber gloves from your hardware store. You might also need materials like a toilet flapper and a replacement fill valve controls or a toilet flush lever if needed. Once you have all the tools ready, follow these steps to stop your toilet from running. 

How to Stop a Running Toilet

Check The Toilet Overflow Tube

To confirm that the problem is with the overflow tube, remove the toilet tank lid and look at the fill tube. This small tube, albeit flexible, runs from the fill valve to the overflow tube in the toilet. Flush the toilet and watch the refill tube as the water tank refills.

It should squirt enough water in the overflow tube to fill the toilet bowl after an entire flush. If you notice that the tube has fallen off or that the water stream is not reaching the overflow tube, then you know that the overflow tube has a problem.

As a result, the toilet bowl will fail to fill, and the next flush will not be efficient. In that case, reattach the fill tube to the fill valve and make sure it holds firmly. It should hold at about one inch above the rim of the overflow tube.

This should ensure that the fill tube sends water into the overflow tube in the toilet. Once you are done, flush the toilet again and watch the water stream flow to make sure it goes down the overflow tube perfectly.

Check The Overflow Tube

If toilet is not a problem and you'd like to fix a leaky bathtub faucet, read this article:

Check The Float Cup And Adjust The Water Level

Your toilet could also be running because of the position of the adjustable float. This is the part of the toilet that controls the level of water in the tank. If the float is positioned very low, your toilet will have a weak flush.

On the other hand, if the float is positioned very high, the water will spill into the toilet overflow tube. In this case, the fill valve will not shut off, and hence, the toilet will keep running. This means that if your toilet does not flush, you need to look at the fill level mark on the inside part of the tank, at the back.

Mark the water level on the overflow tube or measure down about one inch on the overflow tube and mark that spot. Ensure the mark is clear and flush the toilet as you watch and note where the water level will reach the mark.

If the water keeps running even after it reaches the mark, adjust the toilet tank float either up or down. For new toilets, slide a clip along a rod or turn a screw to make this adjustment. If you have an old toilet, bend the brass rod that is connected to the float ball.

This should make the necessary adjustment to the toilet tank float. Stop adjusting the float only when the water shuts off at the appropriate level. One other thing you should do is to check the critical level on your toilet.

Usually, it is marked on the fill valve. Once you find the critical level, ensure that the water level is always at least an inch below this level. Depending on the power of your flush, you can also lower or raise the critical level on your toilet after you adjust the fill height of many valves.

If the fill valve refuses to shut off, it means it is damaged, and you need a replacement. The replacement process will take 15 minutes only. Don't forget to turn the water supply off at the shutoff before you make the replacement.

Adjust The Flapper Chain Or The Flush Handle

Water could be leaking in your bowl continuously if you have a tangled or short chain. This happens because the chain fails to allow the flapper to close as it should. As a result, the fill valve cycles on and off in the act of refilling the tank.

On the other hand, if the chain is too long, the flapper will not open as wide as it ought to, and you will not get a full stronger flush. The same thing will happen if the flush rod hits the tank lid. If this happens, the only way you can complete a good flush is if you hold the lever.

If this is the problem you have identified, you'll have to adjust the linkage in the chain. This should only leave a slight bit of slack when you have a closed flapper. You should also reduce the chance for tangles by cutting off any excess chain at the metal rod.

If you cut, leave only an inch of the chain. When you are done, return the tank lid and ensure the flush valve doesn't hit the lid when the lever is pressed. If the lever is struck, readjust the chain and bend the lever down slightly.

Replace The Flapper

By this step, your toilet should be operating as it should. But if you still find that it is running, then there is a chance that the flapper is worn out. In such a case, turn off the water supply entirely and remove your old flapper to make space for a new flapper.

Start the installation process for your new flapper. It should close and open freely when you test it. Your toilet should not run intermittently or keep running. If this happens, change the flapper and get one with a good seal.

Replacing The Fill Valve

If your fill valve is broken, you are bound to experience unintended or unstoppable refill cycles. The most common sign of a faulty fill valve is a submerged float valve. Opt to replace your faulty fill valve instead of repairing it. A new fill valve is available at various hardware stores. 

Start by turning off the water supply to the toilet. Remove the tank lid and empty the toilet tank by flushing. You can place a plastic bin below the water supply hose since you'll have to disconnect the supply hose from the fill valve bottom side.

Unscrew the locking nut to remove the old fill valve. You'll find it on the bottom of your water supply shank. This will remove the fill valve assembly out of your toilet tank. Any remaining water in your tank will drain in the bin.

Then take the new valve and adjust its height so that it can fit the height of the tank. You can look at the instruction manual for this process. Once you've inserted the threaded end of the valve in the hole in the tank, secure the valve with the locking nut.

Make sure you have a watertight seal without over-tightening the nut. Attach the supply hose to the fill valve and use the pliers to tighten it. The valves refill hose should then be clipped on top of the overflow tube, ensuring that the hose points down into the tube.

The overflow tube should not be below the waterline because it will result in constant refilling. At this point, turn on the water and wait for the tank to refill. The water stops running when it is one inch below the top of the overflow tube. Place your toilet lid back, and you are good to go.

If nothing works and you consider changing your toilet, here are Best Flushing Toilet for you to choose from.

Read more on How to replace toilet stem?


You might think that your running toilet is not something to worry about. But, it can increase your water bills. It is also not suitable for water conservation. Therefore, fix a running toilet as soon as you notice signs of running. This post should help you with the process.

Jim Spencer

Jim Spencer

Jim has been in the construction business for over 12 years with plenty of experience working on client projects, from start to finish. From kitchens to bathrooms and backyard spaces, he writes on a wide variety of topics surrounding home improvement.

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