Home Improvement

How to Stop a Toilet from Running

Africa Studio / Shutterstock.com

Do you hear the sound of a running toilet? It doesn’t only keep you up all night but it can also cost you a lot in the future. Whether it’s just a slow trickle or a constant cycle of turning on and off, it’s still a useless waste of water and can cause:

  • A higher water bill
  • Potential flooding
  • Damage to your septic system

To avoid all of that, take the appropriate actions on time. So let’s not waste any more time and learn how to stop a toilet from running.

Table of Contents

Flushing mechanism of a toilet

Designua / Shutterstock.com

Before you start any repairs, it’s crucial to understand better what you are up against. Have a look at the different parts of the toilet:

  • Handle or dual flush button
  • Fill valve
  • Float
  • Overflow tube
  • Flapper/Flush valve flapper
  • Lift rods

The flapper lifts and releases the water through the flush valve to the bowl. Once the cistern is empty, the flapper closes, forming a seal in the cistern until the next time the handle is pushed. The fill valve turns on and brings water into the cistern. Water flows through the base of the valve, and the refill tube goes to the overflow tube. As the water rises in the cistern, the float ball rises. The float ball shuts the valve off and stops the water once it reaches the fill line.

There are different types of flushing mechanisms, depending on the toilet’s model and design. Here you can see more about them and the toilet cistern.

You may also like:
Home Improvement
5 Simple Ways to Unblock a Toilet Without a Plunger

What causes a toilet to run?

After you’ve gotten familiar with the parts of the toilet, it is easy to identify the issue. Most of the times, a constantly running toilet is caused by one of the following common faults:

  • A bad flush valve flapper. Frequently the flapper wears out because of mineral deposits, wear and tear, and because it’s constantly submerged in water. As a result, water goes through it, causing the toilet to run continuously.
  • Out-of-line lift rods. The lift rod is not above the flapper opening. Thus, the flapper won’t go down all the right way, and the water won’t stop running.
  • The water level is too high. The water is going into the overflow tube. And that means the water level in the cistern is too high. The lower the float ball is, the lower the water level will be.
  • A bad water-logged float. If there is water inside the float, the float will sit in the water at a lower level than needed. This will leave the float valve opened.
  • Fill valve needs cleaning or seal replacement. The float doesn’t rise whenever the water in the toilet cistern is rising, or the fill valve is leaking.
You may also like:
Home Improvement
Leaking Sink: Causes and Solutions

How to stop a toilet from running?

Now that we’ve explained how the toilet mechanism works and determined the common faults, it’s time for the next part. Most of the fixes require no special tools and equipment. However, we recommend you to save some time and frustration by picking up some tools and materials before you start.

Tools and materials required:

  • Cutting pliers
  • Flathead and Phillips (crosshead) screwdrivers
  • Pliers
  • Replacement fill valve washer (optional)
  • Replacement toilet flapper (optional)

Need help? Get emergency plumbing services!

Every drip is wasting water and it needs to be fixed. Let’s roll up our sleeves and check out step-by-step on how to fix a running toilet. All you will have to do are a few simple fixes:

Turn off the water supply

The shut-off valve is located near where the toilet is. Turn the valve all the way to the right until it stops. The toilet will not refill when you flush it.

Check the fill valve

Take the lid off the cistern so you can see what’s going on inside. Even if the problem is not there, it’s good to inspect and clean the fill valve washer (diaphragm) located on the top of the fill valve. Take it off carefully and wash it with warm soapy water. Keep in mind how it goes back. If the seal is old or damaged, it will have to be replaced.

It’s always good to take pictures beforehand, so you remember how to reassemble the parts.

Turn the water back on. If it still leaks, then it is best to contact a professional.

Check the lift rods and the float arm

It should be straight and allow for a smooth up and down, opening and closing operation of the flapper. If not, adjust it until the flapper falls straight down into the opening. Also, make sure the float is not touching the side of the tank wall. Try to bend the arm to the correct position or replace it with a new one if necessary.

Set the fill height by examining the float

Check for a hole in the float that might cause it to fill with water. If it looks good, the next thing you need to do is adjust the float. A general rule of thumb is that the water level in the cistern should be anywhere from 2.5 to 5 cm below the overflow pipe. There’s a little adjustment screw on the top. To lower the float turn the screw to the left. That will lower the float and, in essence, also reduce the water in the toilet cistern.

Check the toilet flapper

Shut off the water supply again for this step. Make sure the flushing valve seal is good. Clean it well or switch the whole flapper out with a universal one or choose a model compatible with the brand of your toilet. If you replace the flapper and the toilet continues to drain down, then the whole flush valve will probably have to be replaced. This action will definitely stop the constantly running toilet.

You may also like:
Cleaning Guides
How to Effectively Remove Stains from Toilet Bowl

How to prevent a toilet from running

There are a couple of things that you can do to prevent your toilet from running:

  • If you hear a strange sound from the filling water in the toilet cistern, clean the fill valve diaphragm.
  • Clean the flush valve flapper and the seal from debris and mineral deposits if your toilet is running for more than 20 to 30 seconds after a flush.
  • Get the right replacement parts on hand. When purchasing replacements for components of your toilet, make sure that they are compatible with the model you have.
You may also like:
Home Improvement
Plumbing Rates in Australia in 2024


  • Don’t postpone a running toilet. This is bad for your mental health and will make your water bill go up.
  • Keep your basic tools in an easy place, so you can reach them fast when needed.
  • Don’t forget to turn off the water supply before you start! 
  • Inspect and test the results after each step.
  • Get the right replacements that are compatible with the brand of your toilet.
  • Consider calling a professional help if you don’t want to waste any more time or things get complicated.

In need of professional plumbing services? Fantastic Services will do all the hard work!

Disclaimer: We are a commercial home maintenance service provider. Our purpose with this blog is to provide valuable and accurate content for solely informational purposes. We strongly advise our readers to consider all the risks and health concerns before taking a DIY project. We also highly recommend you get fully informed about the laws and regulations regarding electrical, plumbing and other work in the different states of Australia.

5 1 Vote
Article Rating
Notify of

Inline feedbacks
View all comments
Would love your thoughts, please comment.x