How to Fix Crack Toilet Tank: Cracked Toilet Tank Repair Guide

A cracked toilet tank is a common household problem that can lead to water leakage and cause significant damage to your bathroom floor. It is essential to fix the crack as soon as possible to avoid a bigger problem.

Fixing a cracked toilet tank may seem like a daunting task, but with some basic tools and a bit of know-how, you can complete the repair easily.

In this guide, we will provide a step-by-step process on how to fix a crack in your toilet tank. By following these simple steps, you can save money on a costly replacement and ensure your toilet is functioning properly again.

Materials You Will Need:

If you do not want to go through extra hassle while fixing a running toilet, it’s clever to gather all the necessary materials before starting the fixing procedure. Here is a list of all the things you need to gather beforehand before starting the repairing process: 

  1. Water-resistant Plumbing Epoxy
  2.  Plumbers Putty (Alternative)
  3. Silicone Porcelain Sealant (Alternative)
  4. Putty Knife
  5. Caulking Gun (Non-mandatory)
  6. Electric Hair Dryer (Non-mandatory)
  7. Sandpaper
  8. Chamois Cloths/Towels/Sponges

Easy Methods to Fix Cracked Toilet Tank


If you’re worried about fixing a leaking toilet tank without the assistance of any plumber or professional, now it’s time to stop worrying. 

With the help of our easiest yet most effective step-by-step methods, you will be able to fix any toilet facilities in no time.

So, without wasting any time, collect your necessary items, and let’s start the fixing process!

Step 1: Turn off the water supply

Firstly, turn off the water supply. Water leakage is a huge problem when a toilet tank gets cracked. If your toilet tank starts to leak water, you should immediately fix it without any delay. Sometimes, cracked toilet tanks don’t leak water; in that case, you can skip this step.

Step 2: Dry the inside and outside of the tank

Now, to apply sealer on the cracked areas of your toilet tank, you need to dry the tank both inside and outside. If the toilet bowl stays wet, then the sealer won’t work, and the process will go in vain. Use chamois cloths or towels, or sponges to dry the tank. Sometimes, using an electric hair dryer also helps to dry the tank out completely.

Step 3: Apply waterproof sealer

When applying a sealer on the cracked areas of your toilet tank, make sure the sealer is waterproof. You can use the waterproof plumbing epoxy or the silicone porcelain sealant that is available. A waterproof sealer will protect your toilet tank from getting cracks in the future.

Step 4: Spread the sealer out on the whole surface

After applying the sealer on cracked surfaces, spread out the sealer on the other surfaces with a putty knife. This will protect the whole surface from getting any cracks. It will also make the sealer symmetrical on your cracked toilet tank.

Step 5: Wait for the sealer to dry completely

Now, wait for at least 24 hours to let the sealer dry out completely. If the silicone/epoxy sealer doesn’t dry off completely, then the cracked areas won’t get fixed. As a result, if you turn on the water, it may start leaking.

Step 6: Turn on the water supply

Once your waterproof sealer gets dry completely, you can turn on the water supply and check the cracked areas. If the water is still leaking from the tank, then turn off the water supply and check the cracked spots thoroughly. 

How to Protect Toilet Tanks from Getting Cracked: Causes and Remedies

Toilet tanks are an essential component of your bathroom plumbing, and they can last for many years if they are taken care of properly. However, they are susceptible to cracking, which can result in water leakage and costly repairs.

Causes of Toilet Tank Cracking:

  1. Age – Over time, toilet tanks can become brittle and crack, especially in older toilets.
  2. Improper installation – A poorly installed toilet tank can put undue stress on the tank, causing it to crack.
  3. Impact damage – Dropping a heavy object on the toilet tank or using excessive force when installing the tank can cause it to crack.
  4. Extreme temperatures – Rapid temperature changes or extreme heat or cold can cause the toilet tank to crack.

Remedies to Protect Your Toilet Tank from Cracking:

  1. Regular maintenance – Regular cleaning and maintenance of your toilet tank can prevent the buildup of mineral deposits, which can cause cracks.
  2. Proper installation – Hire a professional plumber to ensure that your toilet tank is installed correctly and is not under undue stress.
  3. Avoid impact damage – Be careful when handling heavy objects near your toilet tank, and do not use excessive force when tightening bolts during installation.
  4. Avoid extreme temperatures – Keep your bathroom at a moderate temperature and avoid exposing your toilet tank to extreme heat or cold.
  5. Use high-quality toilet tank components – Choose high-quality toilet tank components that are less likely to crack or break, such as durable plastic or metal.
  6. Use a toilet tank liner – A toilet tank liner can help protect your tank from mineral deposits and reduce the risk of cracking.


Repairing a cracked toilet tank may seem like a daunting task, but with the right tools and techniques, it can be easily fixed at home. It is essential to fix a crack in your toilet tank as soon as possible to avoid water damage and costly repairs.

In this guide, we have provided a step-by-step process to help you fix a crack in your toilet tank. Remember to always take the necessary precautions and turn off the water supply before attempting any repairs.

If the crack is too extensive or you are not comfortable with DIY repairs, it’s best to consult a professional plumber for assistance. With a little effort and the right guidance, you can have your toilet tank functioning like new again.

Frequently Asked Questions

How can I repair a crack in a toilet tank?

Answer: You can repair a cracked toilet tank by applying sealer on the cracked spots. If you’re repairing your cracked toilet tank all by yourself, make sure to collect a waterproof sealant.

Can I use any flex seal to fix a cracked toilet tank?

Answer: Yes, you can use flex sealer to fix the cracks on your toilet tank. If you want to use any flex seal, then make sure to use the waterproof one to protect your tank from leaking.

Is it normal to have cracks on your toilet tank?

Answer: Usually, cracks on toilet tanks can cause water leakage and many other problems. If you notice one or more cracks in your toilet tank, then get ready to fix such issues as soon as possible.

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