
You’re probably doing some cleaning or repairs in your toilet, then you accidentally dropped a weighty object on the tank. Your toilet tank is cracked! Now, what do you do? Let’s teach you how to fix a cracked toilet tank in this post.
Yes, we know toilet tanks are mostly built to be sturdy and durable, but did you know your tank can still experience cracking? Factors such as age, accidents, impact, etc, can predispose your toilet tank to crack. When this cracking happens, do you know how to fix a cracked toilet tank?
A crack that is not so serious can be fixed by you. However, if the crack in your tank is significant, professional help may be required. But in all this, a very crucial point is to act fast when this toilet crack occurs.
Never let this crack lingers long so you don’t start having serious leaks. This is because an easily repairable crack can turn into a full-blown crack that will require a total replacement and this can cost you more.
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What Happens When a Toilet Tank Cracks?

Our toilet is one spot in our home that gives us ease when it comes to emptying the body’s waste products. A toilet tank of standard quality built can last for a long time without experiencing any issues. However, as time elapses, it’s possible for the toilet tank to have hairline cracks even though you take all the necessary precautions to avoid them.
The severity of the crack may be determined by the leaks. When your toilet tank cracks, your toilet tank may or may not leak. If it’s a minor crack, then you may be lucky not to have any leaks. However, if the crack is severe, it can predispose your tank to leakage. So, once your tank crack is serious that it causes leakage, immediate fixing will be required.
Common Reasons for Toilet Tank Cracks
Hairline cracks in a toilet can be caused by different reasons. But here is the most common cause:
- Age: as your toilet ages over time, there is a possibility for it to develop a crack. This may be from the manufacturing process that wasn’t even seen based on little imperfections. These little imperfections may not even appear or serve any issue for a long time.
- Accidents: accidents can occur in your toilet. For instance, you might mistakenly drop your toilet lid or any weighty object on your tank which can cause a crack.
- Impact: a serious impact of a heavy object on your toilet tank can cause the tank to crack.
What to do When Your Toilet Cracks?
Once you experience a cracked toilet tank, you will need to make plans to solve the crack immediately. Even if it’s a hairline crack, you will need to take immediate action so it doesn’t get worse.
For instance, if the crack on your toilet is below the tank, especially down the water level, water pressure from that side can further widen the crack. This will again cause leakage and the tank can further break and result in serious damage, especially in your home and property. You wouldn’t want this to happen to you right? That tiny crack can spread over time and cause serious damage if not repaired on time. So, take that fixing step and do it soon! Continue reading to learn how to fix a cracked toilet tank below.
Steps On How to Fix a Cracked Toilet Tank
Hairline cracks can cause leaking toilets and will require immediate repair. So, once you’ve determined that your toilet tank crack is a minor issue, you can perform a DIY repair. Below are the materials you’ll need and a step-by-step guide on how to go about this.

Materials required
- Porcelain sealer (such as silicone plumbing epoxy or waterproof epoxy)
- Putty knife
- Hand caulking gun
- Towel or sponge
- Electric hair dryer
Step 1
First, you’ll need to put off the water supply so you don’t have to worry about water messing up where you’ll be working. Then you’ll also pull the toilet handle to flush to further make the tank clear of water and lift up the toilet tank lid.
Step 2
Next, you’ll need to use a towel or sponge to mob out any excess water from the tank. We recommend you do this step because the porcelain sealer you’ll be using requires a dry area. If the place to be sealed is wet, the sealer won’t work well.
Therefore, take out your time to dry out the area that needs to be sealed appropriately so that you can get a good result at the end of the day.
Furthermore, you can take more steps to dry your tank by using a hair dryer to make your tank dry.
Step 3
Then to the toilet tank crack portion, put some porcelain sealer. A hand caulking gun may be required and this will depend on the type of sealer you’re using.
So, if you’ll be making use of a gun, go ahead and fill it with the porcelain sealer. Now, you can begin the sealing process.
Step 4
With the help of a putty knife or a paper knife, use this to spread the sealer on the cracked area. We recommend you begin applying the sealer from an inch above the cracked portion. Now, move all along the crack part and extend the sealer application a bit below (like one inch) the cracked area.
Step 5
Next, you’ll need to allow the sealed area to get dried. For better results, you can allow the seal to dry for up to 24 hours. Also, make effort to check the other part of the tank just to ensure no crack emerges from other areas.
Step 6
Once, the wait hours have elapsed, go ahead and fill the tank and replace the toilet tank cover. So, as you put on the water supply line, watch your toilet tank refill. While refilling is going on, ensure you scrutinize the tank again for any leaks.
However, if you notice any leak, draining the tank again will be required. Then you’ll check further to see if any cracked part was missed or if the sealed part should be checked again. Do the necessary sealing and test the tank by refilling the tank again.
Once you’ve filled up the tank and there isn’t any leak, your toilet should be good to go. However, if there are still some leaks, then you may need to get a new toilet by replacing the entire tank or you may need to seek professional assistance.
How to Prevent Future Cracks in Your Toilet Tanks
- If you’re working or doing some toilet repair that involve working with your toilet tank, take extra caution not to crack your toilet tank. This is because when doing repairs, there is the probability that your toilet tank will suffer a little break or crack due to the porcelain’s delicate nature.
- When cleaning your toilet, especially the toilet tank part, be careful so you don’t accidentally hit the tank with a sharp object.
- When doing interior replacements in your toilet that involve lifting your tank lid, handle it with care so you don’t drop it accidentally.
- Replace old tanks that are old and due for replacement before it results to a leaking toilet tank.

I am John Kluge, co-founder of Toilethackers.org. With 10+ years of experience working with toilets, I have garnered a lot of understanding about resolving toilet-related issues. Knowledge is meant to be shared and I am passionate about teaching people the right way to keep toilets clean and also fix toilet-related issues. I co-founded this blog to share my experiences and keep readers updated about toilet-related issues. Knowledge sharing is my forte and I always do so with ease. With exceptional writing and analytic skill, I use my skill to simplify complex terms and ensure readers grasp more understanding about toilet issues.