How to Fix a Cracked Toilet Tank

Toilets are prone to cracking. If you just recently cracked your toilet there’s no need to worry, this happens all of the time and there’s affordable ways to have it fixed . Many people crack their toilet tank when trying to place the toilet tank cap/lid back onto the tank. This happens frequently because the tanks lid is very heavy and occasionally it will hit the toilet tank. The toilet tank is more fragile than the lid so it will just crack.

What Happens Once Cracked

The moment the toilet tank cracks it will either start leaking water, or if it’s a crack that doesn’t go through it will not leak water. The crack needs to be fixed because you’ll no longer be able to use the toilet until it’s fixed. You need to call a professional plumber, but first:

Step 1 – Turning Off The Water

If the water is not leaking (which is rare) you don’t need to follow this step, although anytime you’re working on your toilet it’s wise to just turn off the water. The moment the toilet cracks turn off the water immediately. The water will start leaking out onto the bathroom floor and if it’s not turned off there will be water damage issues to the whole bathroom.

Big thing is, turn off the water, the water shut off valve is usually behind the toilet. It should just take a couple seconds.

Step 2 – Dry Out the Tank

It’s tempting to be lazy here and not dry out the tank. Always and always, always dry out the tank. It’s not the funnest part of the job, but what part is fun? Get towels, or anything that can pull out the water. Squirt guns can pull out the water, do what you have to do. Just make sure that tank is completely dry and the water is shut off. The porcelain sealer will not dry if there’s water.

Step 3 – Find a Porcelain Sealer or Use Epoxy

Epoxy sealer can be found at Home Depot for just a few bucks. Any porcelain sealer can also work. Be sure to check with plumbing experts to see if the specific branded sealer is good choice. Once you find the sealer, you’ll be ready to repair the crack.
*Note – The the crack is bigger than 1/16 of an inch, chances are your best option will be to get a new tank.

Step 4 – Apply the Sealer

Depending on the porcelain sealer you will most likely need a caulking gun. Fill the caulking gun with the sealer, and get started. Start an inch above the crack and slowly work your way down the crack and fill in the crack with the sealer.

Step 5 – Smooth Out the Sealer

For this you can take out a paper knife, or any tool that will help spread out the sealer over the crack. This will make the toilet look better, and will prevent other side cracks from starting. Remember – these toilet tanks are very fragile.

Final Step – Let it Dry

Let the tank dry for at least 24 hours. It’s not fun having to use another toilet, but this will protect the sealer from leaking if it’s given a good amount of time it dry. Turn back on the water, the test away to see if it still leaks.


No toilet is perfect, cracks and hairline cracks happen all of the time. The toilet tank crack is not expensive, just slightly annoying. Good luck on getting it fixed.