How To Fix a Cracked Toilet Tank

Cracks in toilets are easy to detect as these are mostly plumbing problems. In some cases, there are chances of getting cracks in a toilet while manufacturing it, but it may not appear for several years. The other reason for cracking might be including an unexpected crack that starts leaking. The severe temperature changes may contribute to developing a crack that starts leaking out all from all over. You should fix these problems to avoid further damage.

There are chances of developing cracks in the toilet tanks below or above the level of water and either on the outside or inside. Depending on the location of the crack, you can determine the remedy.

Types of Cracks

A Crack Above the Water Level

This is not a big issue till the time the crack grows gradually. If you notice a toilet crack in the tank, you should mark it and then keep an eye on it so that the condition does not get worse. You should also take a picture for your convenience. It will be helpful later on.

A Crack Below the Water Level

You must repair this right away. Unfortunately, a crack located in a toilet tank is tough to spot. If you doubt a leak from the tank, begin checking the seals. The next step is to check out the tank carefully to locate a crack in the porcelain. You should analyze either inside or outside the tank to find the damaged part.

Locating Cracks in a Toilet Bowl

If you have found water on the floor just near the toilet, it may indicate the possibility of a leak. You should consider that the water leak only when you flush the toilet, so replete while you test around the bowl to locate a crack that is the real cause of the leak. It can be hard to identify, so check daily to make you able to gets off this problem.

A Toilet Bowl Crack – Above the Level of Water

This crack is a concern, but you can ignore it. If the crack does not seep at all just because it is located at a place that has a minimal flow of water, you may leave it as it is. However, mark both sides of the crack, and regularly check whether it is growing or not. A click may be helpful for this purpose.

A Toilet Bowl Crack – Below the Level of Water

Such types of cracks that are present below the level of water are somewhat perplexing. These are almost impossible to locate because of the bowl shape. If the visibility of the crack in the toilet bowl is marked, then you will possibly need to replace the previous toilet.

An Invisible Crack

This is also a chance of having an invisible crack, and it has two types of indication symptoms; standing water present on the floor or losing water. A small invisible leak may lead to the accumulation of water on the floor near the base of the toilet. Less frequently, this happens that the water from the bowl will gradually leak out into the drain rather than onto the floor. If the toilet appears to mysteriously start losing its water, then you may have a cracked toilet that seeps into the drain.

Fixing Options

If you notice a hairline crack in the bowl or the tank, you may be able to resist the leak with the help of waterproof epoxy that aids in healing. Epoxy can also be useful for cracks at the base of the toilet, such as breakage or cracks around the locks or bolts that ensure the toilet sticks to the floor.

Cracks that have the possibility of developing under the water line are even harder to spot, but the use of epoxy is helpful in this case. If it doesn’t work, the only alternative is to replace it.

Waterproof epoxy is present in two parts that you blend immediately before you apply it to the crack. Most of the time, epoxy starts hardening in 15-30 minutes. Select an epoxy rated for usage on porcelain sinks and tubs.

You Will Require…


  • Bucket and sponge as per your requirement
  • Putty knife

Materials Required

  • Cleaning supplies
  • Sandpaper
  • Waterproof epoxy


Drain the Toilet

Turn off the supply of water to the toilet present at the shutoff valve located below the toilet tank. Then, turn it clockwise till it stops. Next, flush the toilet so that the water drains from the bowl and tank. Remove all the standing water in it; if necessary, soak it up with the help of a sponge or wringing it out in a pail. Afterward, wipe the porcelain to dry it.

Neat and Sand the Fix Area

Clean the area at the crack site thoroughly to confirm that there isn’t anything on the surface of the porcelain. Then, sand that area with sandpaper so that surface gets rough; sand just where you will apply epoxy. Wash the area well and allow it to dry. (Also, while you can apply waterproof epoxy to wet surfaces, it’s relatively easier to operate on a dry surface.)

Blend and Apply Epoxy

Now, mix the two parts of the epoxy, as per directions delivered by the manufacturer. Immediately after applying the blended epoxy to the crack with a putty knife or spreader, spread it evenly and flatten the epoxy in the best possible way. You must apply the epoxy within the working time of the material; usually, it does not exceed 30 minutes.

Allow it to cure overnight, or as per the recommendation of the manufacturer.

Refill the Toilet and Check

To test it, open the shutoff valve to the toilet by turning the handle counter-clockwise. Allow the tank to refill, then flush it again and trial for leaks.

Final Thoughts

You can seal or fix toilet cracks easily. However, they can be hard to deal with; it all depends on the crack’s location. Routinely noticing these things will help you rectify the problem before even it occurs.

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