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Leaking toilet – Find the cause, limit further damage and get it fixed

A leaking toilet is no laughing matter. If you don't get it fixed, you leave yourself open to water damage, high water bills, and a generally unpleasant experience. So, if you're dealing with a leaky toilet, let's flush out the problem and get your throne back in good working order.

When nature calls, being met with a leaking toilet is a frustrating problem for anyone. Whether your toilet is leaking at the base or toilet water is leaking into the bowl, if you don’t get the problem fixed asap, it can cause significant damage to your home.

Thankfully, with some basic knowledge and a little elbow grease, you can fix most leaking toilet issues by yourself. Keep reading for our expert advice on who to call, how to make repairs yourself, and what steps to take while you’re waiting for a plumber.

If it’s an emergency, find a plumber now!

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What is the most common cause of a leaking toilet?

The most common issue that causes a leaking toilet is a faulty flapper valve. The flapper valve is a rubber or silicone seal at the bottom of the tank that opens and closes to allow water to flow into the bowl.

When the flapper valve becomes damaged or worn, it no longer creates a tight seal. This allows water to leak from the tank and into the bowl. (See image below).

Toilet flushing mechanism

What is a toilet flapper?

A toilet flapper is a rubber or silicone seal found at the bottom of a toilet tank. Its main function is to control the flow of water from the tank into the toilet bowl when the toilet is flushed.

When you flush your toilet using a lever or push button, the flapper lifts and lets water flow from the tank and into the bowl. This water then washes your waste away and out of sight.

Once the tank is empty, the flapper closes to create a watertight seal and prevent water from leaking out of the tank and into the bowl.

Due to the traffic it receives, the flapper often becomes damaged or worn over time. As a result, it no longer creates a tight seal, which results in water leaking into the bowl or – worst-case scenario – your bathroom!

If this has happened to you, the flapper should be replaced to prevent further damage and/or water wastage.

plumber fixing a toilet that won't flush properly

Other issues that cause a leaking toilet

Here are some other known issues to look out for when it comes to a leaking toilet.

Cracked tank or bowl

A crack in the tank or bowl can cause water to leak out. If you notice water leaking from the base of your toilet, it could be a sign of a crack in the bowl.

Loose or damaged bolts

The bolts that secure the tank to the bowl can become loose or damaged over time, causing water to leak out of the tank.

Corroded or damaged pipes

Corrosion or damage to the pipes that connect the toilet to the water supply can cause leaks.

High water pressure

High water pressure can cause water to leak out of the tank or bowl.

An improperly installed wax ring

The wax ring that seals the base of the toilet to the floor can become damaged or improperly installed, causing water to leak out of the base of the toilet.

If you notice any of these issues, try to address them as quickly as possible to prevent further damage or water wastage. For concerns you can’t fix yourself, contact a professional plumber who’ll help you diagnose and repair the issue.

Better yet, pop your postcode into the form below and we’ll get one of our experts to call you asap.

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What to do when an issue occurs and limit further damage

If you suspect your toilet is leaking (or it’s obvious due to all the puddles), follow these steps:

  1. Turn off the water supply to the toilet first and foremost
  2. The easiest way to do this is to turn off the shut-off valve, which is usually located behind the toilet
  3. Turn it clockwise until it stops
  4. Remove your toilet’s tank lid and inspect the components inside for any signs of damage or wear
  5. Identify the issue and either attempt to fix it yourself or call a professional

How to repair a flapper valve yourself

If you’ve worked out that the flapper valve is causing the leak, you’re in luck because it’s relatively easy to replace. Just follow these three simple steps:

Step one: Stop and remove the water

Turn off the water supply to your toilet by turning the shut-off valve clockwise. Then flush the toilet, which will drain the water from the tank.

Step two: Remove the leaky flapper

Remove the old flapper valve by disconnecting it from the chain and lifting it out of the valve seat.

Step three: Replace the flapper with a new one

Replace the old leaky flapper with a new flapper valve (one you’ve purchased online or from your local hardware store to match your toilet’s make and model). Make sure it creates a tight seal when closed.

If you notice any cracks or damage to the tank or other components, we recommend calling a professional plumber to repair or replace them.

However, if the issue is simply a loose or damaged fill valve or flush valve assembly, you can repair them using a few basic tools.

How do you fix a leaking toilet cistern?

If you have a leaking toilet cistern, it could be due to a faulty inlet valve, outlet valve, or overflow pipe. Here are some steps you can take to fix a leaking toilet cistern:

  1. Turn off the water supply to the toilet and flush the toilet to drain the cistern.
  2. Check the inlet valve for any signs of damage or wear. If it’s damaged, replace it with a new valve.
  3. Check the outlet valve for any signs of damage or wear. If it’s damaged, replace it with a new valve.
  4. Check the overflow pipe for any signs of damage or blockage. If it’s damaged or blocked, clear the blockage or replace the pipe if necessary.

By taking these steps, you can fix a leaking toilet cistern and prevent water wastage and damage to your home.

If the issue persists, you may have a crack in the cistern or a faulty seal. In this case, it’s best to call a professional plumber to diagnose and repair the issue.

How to prevent toilet leaks in the future

Make sure you perform regular maintenance on your toilet, such as cleaning the components and checking for signs of wear and tear and/or damage.

Additionally, avoid flushing anything other than toilet paper and human waste down the toilet. Foreign objects are one of the biggest causes of clogs, and they also damage your toilet’s components, causing costly repairs or emergency call-out fees.

Who to call to fix a leaking toilet

If you can’t diagnose or repair the leak yourself, it’s time to hire a professional plumber. They have the knowledge and experience to quickly and efficiently repair any leaks or damage to your toilet. They’ll also help prevent further damage to your home.

Related content: How can I fix my toilet flush?

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FAQs

Can you replace just the toilet tank?

Yes, you can replace just the toilet tank without having to replace the entire toilet. If the tank is cracked or damaged, you can remove and replace it with a new one (as long as the new tank is compatible with the existing bowl!)

To replace the tank, turn off the water supply to the toilet, drain the tank by flushing the toilet, and then remove the nuts and bolts that hold the tank to the bowl.

Lift the tank off the bowl and replace it with the new tank, making sure to use the same nuts and bolts to secure the new tank to the toilet bowl.

What do I do when my toilet is leaking into the bowl?

If you notice water leaking from the tank into the bowl, it’s likely due to a faulty flapper valve. To fix this issue, turn off the water supply to the toilet and flush the toilet to drain the water from the tank.

When you’ve done that, remove the tank lid and inspect the flapper valve for any signs of damage or wear. If it’s damaged, replace it with a new flapper valve and make sure it creates a tight seal when closed.

Additionally, check the chain that connects the flapper valve to the flush handle, ensuring that it’s not too tight or too loose. If the chain is too tight, it can prevent the flapper valve from closing properly, causing the toilet to run continuously.

What do I do if my toilet is leaking from a pipe at the back?

If you notice water leaking from a pipe at the back of your toilet, it could be due to a faulty fill valve or a loose connection. In this case, follow these steps:

  1. Turn off the water supply to the toilet and flush the toilet to drain the water from the tank.
  2. Inspect the connection between the fill valve and the pipe, ensuring that it’s tight and secure.
  3. If it is loose, tighten it with a wrench or pliers.
  4. If the connection is secure, the fill valve may be faulty and need replacing.
  5. To replace the fill valve, disconnect the water supply line from the valve, unscrew the valve from the bottom of the tank, and replace it with a new one.
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