Why Water Leak from Toilet Tank? [4 Major Causes & Solution]

Why water leak from toilet tank

No doubt, a leaky toilet tank is a common problem that, once it comes out, can’t go ignored for a long-time. The leak problem may come out anywhere. There are plenty of reasons I found which are the main culprit to leaking your toilet tank.

Why water leak from toilet tank? It is hard enough to say the exact answer in one word. According to my experience, there are 4 major problems which leak the toilet tank. These problems you need to find out and solve as soon as possible. Stay tuned to get a clear concept.

Why Water Leak from Toilet Tank?

From this section, you will discover 4 water leaks from the toilet tank problem. These problems are common, and you will find them in most households. Moreover, you will also get the best solution besides the problems.

1. Worn Out Stuck Flapper

One of the most common problems stuck the flapper worn out. A flapper is a machine that is designed between a tank and blocks. It enters your toilet bowl from the water section.

When the flapper is worn out or stuck, your toilet tank faces leak problems. It is not only caused leak problems but also causes the loss of a high amount of water, which increases the water bill.


If you find your flapper stuck, you can fix the problem by removing the flapper and cleaning it properly. When the flapper is worn out, you should choose a new one and then fix it as soon as possible.

2. Faulty Fill Valve Float

Your fill valve is the hollow ball that acts like a sensor and lets the toilet tank know when it refills the water. But what happens when your toilet tank comes with a faulty fill valve float, the water leak of the toilet tank, and also avoid refilling with water.

When the toilet tank doesn’t refill with water, you may not flush the toilet properly. Though it is not a major problem, you may often find this problem.


To fix the problem, you have to choose the right fill valve float for your toilet. It is truly essential for you to remove the valve and clean it properly. If you think that the valve is not workable, you can replace it with a new one.

3. Rusted Pipe

It is a little bit tricky to find out if the pipe is rusted or not because you need to start from the beginning. Rust pipe is also another culprit which causes leak problems in your toilet tank. Moreover, the rusted pipe also causes damage and break problems.


First of all, you need to find out the rusted pipe. After finding the rusted pipe, you need to clean it properly. You can use vinegar and baking soda to clean the pipe properly way. If the pipe is damaged badly, I would love to suggest you buy a new pipe and assemble it properly.

4. Flushing Problem

Most of the toilets come with two flushing systems, such as single and double. If the flush system produces extreme pressure, the flush valve sometimes doesn’t work properly and creates a leakage problem.

Though it is not a common problem, you will find this problem after using the double flush system continuously. So, it would help if you used a single-flush system toilet.


When the flush system comes with extreme pressure, you can reduce the over-pressure to fix the problem. You can change the flush valve to fix the problem.

Water Leaking from Bottom of Toilet Tank When Flushed

Water leaking from the bottom of the toilet tank when flushed because of losing a mountain bolt or a worn-out wax gasket. On the other hand, the problem also comes out because of assembling problems.

A problematic water shutoff valve also causes this problem. The toilet bowl valve also causes this problem. So, it would help if you assembled the bottom area of the toilet properly. Don’t forget to tighten the toilet bolt properly to fix the problem.

Toilet Tank Losing Water but no Leaks

If your toilet tank loses water but has no leakage, your toilet comes with a clogged vent problem. Moreover, the toilet valve also created this problem. So, you need to change the level when it happens.

On the other hand, the stuck refilling valve also created this issue. Try to clean the valve properly and then reassemble the valve to fix the problem.

FAQs (Frequently Ask Questions)

Q: How do I stop my toilet tank from leaking water?

Answer: If you want to stop the toilet tank from leaking water problem, you need to find out the actual reasons and then solve the issue. For example, the toilet tank leaking water comes out because of the worn-out stuck flapper, which you need to fix.

Q: Why is my toilet leaking from the bottom of the tank?

Answer: Your toilet is leaking from the bottom of the tank because of the floor mount bolt problem. You may find the bolt loose enough. On the other hand, the installation problem also causes this problem. Most important, you need to check out the valve of the tank to get a better solution.

Q: What is the most common toilet leak?

Answer: The most common toilet leak is a worn-out stuck flapper, faulty valve, installation problem, flushing problem, and so on. These are the main culprits which make the toilet tank leak. These problems also waste a high amount of water.

Wrapping Up!

Most of the time toilet tank leaks because of the valve and worn-out flapper. These two problems are common, and you should check them out first. Moreover, you may also find a rust pipe problem, which also causes a leak problem. I suggest you check out the above article to find out the problem and solution.

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