23 June Repair tools on top of a toilet with a closed lid

How to Fix a Running Toilet

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For homeowners all over the world, one of the most worrisome and inconvenient problems that they can encounter is a leaking toilet. Additionally, the signs of a leaky toilet usually only become pronounced and noticeable when the leak has gotten bad – meaning that the moment you notice a leakage, repair needs to be done ASAP. Leaks can cause the toilet to keep running which will then add to your water bill, wasting an average of 26 gallons per day.

Keep in mind that if the leak is rapidly progressing or if you are undergoing a plumbing emergency, reach out to a plumbing expert as soon as you can – and also, you may want to skip over to this section of the article: The Leak is Really Bad – What Can I Do RIGHT NOW?

In this article, we will cover the main causes of why toilets leak, how to fix a running toilet, whether or not DIY repairs are safe, and more. Let’s get started.

What are the Signs That a Leakage is Causing My Toilet to Keep Running?

Toilet leaks can manifest in different ways because the cause and the extent of the leak depends on every individual case. In most cases, toilet leaks will cause your toilet to keep running. Sometimes the signs are more glaringly visible than others.

If you want to be absolutely sure, here is a full list of signs that your toilet keeps running because of a leak. If you notice even just one of these signs, it’s definitely worth looking further into.

The Toilet is Noisier Than Usual

Running toilets would constantly make noise after each flush. This is usually because of a leak in the toilet tank or a problem with the fill valve.

There’s a Puddle/Staining/Dampness Around the Bottom of the Toilet

The presence of water around the base of the toilet can take the form of dampness, staining, or in more severe cases, a puddle. This can suggest various problems such as a leaking supply line or a cracked toilet tank.

The Tank is Leaking

This can be in the form of visible drips or moisture on the tank of the toilet. If you’re not sure where the leak is coming from or if there is a leak, one way to find out is to put drops of food colouring into the tank and see if the colour shows outside.

Dampness around the base of the toilet due to leaking

The Leak is Really Bad – What Can I Do RIGHT NOW?

If the leak is already really bad at the moment or you fear that it’s progressing and could cause flooding, the best thing to do is to cut the water supply to the toilet. There are two ways to do this.

Method 1: Close the Shutoff Valve

The football-shaped shutoff valve of your toilet can be found connected to a pipe or hose attached to the bottom of the tank of your toilet with the other end connecting to the wall.

  1. Simply turn the valve clockwise until it cannot be turned anymore, meaning the valve is completely closed. If the valve is difficult to turn, avoid forcing it. You may need to try applying some WD-40 to it. If it still doesn’t turn, resort to method 2.
  2. Time to check if it worked. There are two ways to do this.
  • Flush your toilet. If the water supply is successfully turned off, the tank will empty out into the toilet bowl and not be refilled afterwards.
  • If you are trying to avoid flushing your toilet (e.g. because it is clogged), you can try to lift the float lever in the tank. If no more water is added to the tank after you do this, then the water supply is successfully shut off.

Method 2: Close the Main Shutoff Valve

In some cases, such as when shutting off the valve near your toilet does not work, you would need to close the main shutoff valve. This is located near the water meter which is usually in the basement. The main shutoff valve would be one or two circular wheel-like handles near to the water meter. In some, these can be lever handles instead.

Note – If you cannot locate this and you also cannot succeed with method 1, the best thing would be to contact an emergency plumber as soon as possible.

  1. To shut off the main water supply, turn the valve clockwise. If there are two valves, turn the one that is closest to your home.
  2. To be absolutely sure, you can check your toilet if the water supply has successfully been cut. Refer to step 2 of method 1.

Close up of the main shutoff valve - the circular type

After shutting off the water supply, make sure to call in an expert plumber so you can get your problem fixed as soon as possible.

Top Possible Reasons Why Toilets Run and How They’re Fixed

Leaking Supply Line

The supply line is the pipe or hose that brings water into the tank of the toilet for the flush to work. This line is connected to the supply valve and to the toilet’s tank. Usually, a problem arises when the joints in the supply line become loose or weak. The rubber lining of the supply line can also be ruptured. These issues are brought about by physical force or simply wear and tear. This problem is fixed like so:

  1. First, the water supply to the toilet needs to be cut.
  2. Next, the water is removed from the tank – usually by flushing until the tank is emptied.
  3. The faulty supply line is then disconnected from the valve and then from the toilet.
  4. The new supply is then connected to both valves.
  5. The water is turned back on and the new supply line is tested if leaks no longer occur.

Most homeowners are confident to do this repair themselves. But some issues can happen if the problem is misdiagnosed or if the repair isn’t done correctly.

Damaged Toilet Tank

The toilet tank holds the water for flushing that comes from the supply line. The most common reason why damage happens to this part of the toilet is physical impact. Even really small cracks that are not easily seen can cause leakage which can then lead to the toilet running incessantly. Luckily, small enough cracks can mean that you won’t need to have your toilet replaced. However, locating the smaller cracks can be a challenge.

A good trick to find out where the leaks are coming from is to put food colour into the tank’s water. Then watch where the colour would show up on the outside of the tank. If you can rule out that this is the only problem with your toilet and have been able to locate the crack/s, this can be safe enough to DIY. Here’s how to seal the cracks.

  1. First, the water supply to the toilet needs to be cut.
  2. Next, the water is removed from the tank – usually by flushing until the tank is emptied.
  3. After the outside of the tank is dried as well, you can use either a porcelain sealer or epoxy. Start from an inch before the crack and trace through the crack until an inch after it.
  4. Smooth out the sealer with a plastic knife and let it sit for 24 hours.
  5. Once this is all done, the water can be turned on. Check to see if the leak is still present.

Faulty Toilet Float

The toilet float is the ball that you can see floating on top of the toilet tank’s water. Its purpose is to trigger the mechanism of refilling the water in the toilet tank when the water is too low. When the toilet float is damaged, the fill valve will tend to run continuously. The common causes of why this part of the toilet is failing are wear and tear and/or physical damage. The solution is to replace the toilet float – which can be done with the following steps:

  1. First, the water supply to the toilet needs to be cut.
  2. Next, the water is removed from the tank – usually by flushing until the tank is emptied.
  3. Pliers are used to unscrewing the arm of the old toilet float and it is removed from the tank.
  4. The new toilet float is threaded and screwed into place, securely connected to the fill valve.
  5. The water is then turned on again to check if the leak has been resolved.

Some homeowners may be confident enough to do this replacement themselves but we will always recommend getting an expert on board. This will ensure that the problem is properly diagnosed and effectively addressed.

Fill Valve Problems

The fill valve is the apparatus that allows the toilet tank to be refilled after flushing. This part of the toilet goes through wear and tear over time. The damage will mean that the fill valve will be unable to shut off. When this valve fails, the toilet keeps running and this can reflect on your water bill. The solution is to replace the fill valve – which can be done like so:

  1. First, the water supply to the toilet needs to be cut.
  2. Next, the water is removed from the tank – usually by flushing until the tank is emptied.
  3. The supply line would then need to be detached from the tank.
  4. Next, the faulty fill valve is removed.
  5. The new fill valve’s height is adjusted and then it can be installed into the tank.
  6. Once all this is done, the supply line is reconnected to the tank and the water is turned on to check if the leak has been resolved.

Although many can consider this process to be DIY-friendly, we can’t reiterate enough that DIY can be prone to misdiagnosis and faulty repairs that can have immediate or gradual repercussions. Save time and effort by calling in a plumber to do the job.

Top view of a toilet tank

How Recommendable is DIY Toilet Plumbing?

Though DIY plumbing can be tempting to do because it looks like the most cost-effective solution, it usually isn’t. Mistakes can happen and you may end up calling up an expert plumber anyway to fix the same issue the second time around. Even worse, the issue may be aggravated and would mean a costlier repair. Additionally, DIY plumbing may not be the safest solution and accidents and/or water damage will add to your cost.

By having an expert on board, you avoid the above headaches and you can be sure that your repaired toilet will serve you for a long time without hiccups.

Where Can I Get Expert Help?

Here at PlumbWize, our expert plumbers can get the repair done right the first time. We can quickly and easily fix up your toilet for you! We service areas around Burlington, Oakville, and Hamilton.

We specialize in various plumbing services including residential plumbing services, commercial plumbing services, Kitec replacement services, frozen & burst pipes repair services, and more. You can also ring us up in case of plumbing emergencies. Whatever your plumbing needs are, we’ve got you covered. Contact us today!


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