How to Stop a Toilet from Running? 3 Steps to Solve!

Even after many years of technological advancements, a few things have changed about how a toilet functions. The toilet still uses the same mechanism as it used several decades ago. There are a few causes that stop a toilet from running.

A faulty fill valve or flush valve are two main reasons for a running toilet. It can increase the water bill by wasting up to 200 gallons of water per day, which is $2.35. But how do you tell if the problem is with the fill valve or the flush valve? Just pour some food color in the toilet tank and flush the toilet.

If the flushing water in the bowl is clear (without color), the problem is with the fill valve. If the toilet flushes colorful water, the problem remains in the flush valve. Fill valve replacement may cost $15–$35, while flush valve replacement may cost $20–$150.

Toilet Flushing Mechanism

Different toilet brands offer different types of flushing systems. When you flush the toilet, the chain lifts the flapper and allows water in the tank to flow into the bowl. After releasing all the water in the bowl, the flap drops and seals the opening. Next, the tank fills, and the float, which is connected to the float valve, opens and closes when the tank is full. If the water in the tank is in excess, the overflow tube in the tank’s center drains the water into the bowl.

What causes your toilet to run continuously?

If your toilet has constantly been running and you are wondering how to diagnose it, you’re in the right place. But before that, it’s crucial to know what’s causing your toilet to run. Here are some of the usual suspects:

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A faulty flush valve

This is one of the first components to look out for when your toilet doesn’t stop running. Also known as the flapper, the flush valve is meant to seal the tank properly and prevent water from leaving the tank to the bowl. However, after several years of use, the flapper can wear out and become less effective in performance. In that case, you have to buy a new flapper.

Faulty float ball

Another culprit can be a faulty or poorly placed float ball. After flushing the toilet, the ball drops and opens the inlet valve on the fill tube. When water flows into the tank, the ball rises, hence, closing the valve and stopping the water from flowing into the tank. Therefore, if the ball is damaged or poorly installed, it might not lock the valve properly, causing the toilet to run.

Length of the chain

The chain’s work is to allow water to drain from the tank to the bowl. The chain is usually attached to the flusher and flapper. When you flush the toilet, it lifts the flapper and allows water to drain into the bowl. Hence, if the chain is too short or too long, it may fail to close the flapper properly.

Bad refilling valve & tubes

The works of refill are to refill the tank after flushing. An adequately installed refill tube should be above the surface of the water when your tank fills. If the water surpasses the refill tube, then you will have a constantly running toilet.  

A bent lift arm

If your toilet’s lift arm is bent, it will also make your toilet run. This is because it may allow excess water to flow into the tank and pass the required level.

Wrong water level

The problem is associated with the toilet fill valve. Every toilet comes with a standard water level. If the water level in your tank fills beyond the recommended level, you will have to adjust it, or the toilet will continue to run.

Related article: Best Ways to Clean a Toilet Properly

How to stop your toilet from running?

However some latest toilets have a few variations, but the concept is still the same. If you know how a bathroom works, diagnosing the common toilet issue can be super easy. And since the toilet hasn’t changed a lot, we face the same challenges our great-grandparents faced a few decades ago. Now that you know what causes your toilet to run, here is a step-by-step guide on how you should stop a running toilet:

Step 1: Inspect a flapper and its chain

How to Stop a Toilet from Running?

As highlighted above, the first part to check when you have a running toilet is the flapper and its chain. 

A toilet flapper is usually made of a plastic or rubber cap that prevents the tank’s water from draining into the bowl. At times, the chain may be too short or long, allowing water to flow through to the bowl.

To determine if the flapper is worn-out or damaged, fill the water tank and monitor the flapper’s consistency. Besides, you can also touch the flapper and feel it, whether it’s hard or soft. If it’s hard, it will not seal properly and needs to be replaced.

Related article: How to Unclog a Running Toilet Without a Plunger?

If the flapper is fine, inspect the chain. The chain shouldn’t be too long or too short. Adjust it to the right height. Additionally, you should make sure the chain isn’t catching on to anything. And finally, if the chain is rusty, replace it with a new chain.

If the flapper and chain are okay, ensure that the flapper is seated in its right place. If the flapper is dislodged, it will pass some water and make the toilet run. So, adjust it to its proper position. But it would be ideal for replacing the flapper if it is damaged. Flush and drain down the remaining water from the toilet tank before you replace the flapper.

Step 2: Inspect the float

How to Stop a Toilet from Running?

Adjust the float water level in the tank to fix a running toilet. If the float is positioned extremely low, it will produce a weak flush. And if it’s set too high, water will spill into the toilet overflow tube flapper, and the fill valve won’t stop water from flowing into the tank. As a result, the toilet will continue running.

Fixing such an issue is simple and straightforward. Remove the tank lid and check the mark where the water level should be. If the water exceeds this mark, you need to adjust the float. Twist the valve shaft clockwise to lower the water level in the toilet tank. Flush and fill the toilet to see if the water level is okay. For older toilets, you may have to bend the brass rod that links to the float ball.

Step 3: Inspect the refill valve

How to Stop a Toilet from Running?

If the float is okay, your next stop should be to inspect the fill valve. The work of the fill valve is to control the flow of water into your toilet tank. A damaged or faulty fill valve may fail to turn off or may shut off the water intermittently. As a result, this may cause unintended refill cycles. One of the common signs of a bad fill valve is a submerged float valve. So it would help if you changed the faulty fill valve with a new one.

Since fill valves are cheap and straightforward to replace, you’re better off replacing a damaged or faulty valve than replacing it. Besides, you don’t need a professional plumber to replace it. Here is the procedure for replacing a bad fill valve:

Turn off the water, remove the tank’s lid, and flush the toilet. Next, disconnect the water supply hose, and remove the old fill valve by unscrewing the locking nut on the bottom of the supply shank. Remove the whole fill valve assembly and replace it with a replacement fill valve assembly. Follow the manufacturer’s instructions and secure the new fill valve with the locking nut. Re-attach the water supply hose and turn the water back.  If the toilet is no longer running, you have fixed a running toilet problem.


With this guide, stopping your toilet from running shouldn’t be a big deal. You don’t have to get the services of a professional plumber, as most issues can be fixed quickly and straightforwardly. You just need to follow a few simple steps to fix a running toilet. Make sure to identify the problem so that you can have a smooth time and save time. All the best as you stop the toilet from running and keep your water bill!

Hi, this is Robert Crossan, the owner of this website, has 17 years of experience in the installation, maintenance, and repair of toilets and plumbing systems. After completing the Level 2 Basic Plumbing course in 2005, I started working in both domestic and commercial buildings as a professional plumber. So I can figure out the core difference between different toilet models and brands. It also helped me monitor their work performance and setbacks.

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