Slow and Steady: How to Fix a Slow Filling Toilet Tank?

How to Fix a Slow Filling Toilet Tank? The toilet is an important household tool in every house. If you ever encountered a slow-felling toilet, you should have known how much frustrating it can be. Most of the toilet takes 2 minutes to fill after every flush

In some cases, 3 minutes at the most. But if your toilet tank fills really slow, then it must be a problem. You may ask yourself, why is my toilet tank filling up so slowly? 

Well, there may be several reasons behind this particular issue. You need to find the real reason behind this incident first to get rid of this. So, here’s a complete guide what are the reasons behind and how to fix a slow-filling toilet tank.

Read: What to Put on Toilet Tank for Decoration?

Reasons Behind a Slow-Filling Situation

Reasons Behind a Slow-Filling Situation

If you are worried about what causes the toilet tank to fill slowly, we should remind you there is more than one reason behind this. Let’s see through them:

Water supply valve

The most obvious reason behind this could be that you unconsciously shut off the water supply valve. Or you may open it partially, letting the toilet water flow more slowly than expected. So, the tank will take time to fill up to the required water level.

Clogged drain

Another most obvious reason could be a clogged drain. The bottom of toilet tanks may get clogged by debris. It will prevent the toilet water from properly flowing and reaching out from your toilet bowl.

Low water pressure

Another reason behind a slow filling tank can be low water pressure. Slow water pressure is the result of many reasons. Sometimes it happens due to damaged pipelines. Sometimes, for the clogged vent or drainage. Either way, you may not find them even after taking the utmost care. In these cases, a plumber can help you.

Blocked pipe

A blocked pipe causes slow water level gain. Blocked pipes are not necessarily the result of debris. You may have dropped a toilet paper or some other tool. It went straight through the pipe and blocked it partially.

Clogged vent

A clogged vent can result in a slow-filling toilet tank. Vents are the most important part of a toilet tank. It evacuates the air from inside of the tank, which later helps the toilet water to fill inside it. But if somehow the vent is clogged with debris or other types of corrosion, then your toilet may take more time to fill.

Dirty or damaged flash valve

 A toilet flush valve or flapper is another important part of your toilet. A dirty toilet flush valve will resist the proper water flow. Besides, if it is somehow damaged and the water starts to leak then you can face the same problem.

Leaking toilet valve or pipe

If you can’t find anything like none of the above-mentioned reasons, then you should check for a leaking toilet valve. It’s the last but not least reason behind your slow-filling tank. You should check every part of the water valve. 

Read: How Many Gallons Does a Toilet Tank Hold?

How to Fix a Slow-Filling Toilet Tank?

Well, now that you know about all the possible wrongs with your toilet tank, let’s focus on the solution. So here’s how to fix a slow-filling toilet tank:

Always keep your water supply valve on

Toilet tanks need to be fulfilled before they can provide you with another flush. So keep your water valve on fully, not partially.

Check for a clogged drain.

To clear a clogged toilet drain first remove the upper cover of the tank. Now carefully pour some vinegar. You can also apply some baking soda paste(a mixture of water and soda). Now let it sit for about 30 minutes, and then use the flush to get rid of those.

Fix the low water pressure problem

Try to unplug all the valves or pipes from the toilet and check for any kind of damage or dirt in the pipes. If you find any of them, simply clearing them will solve the problem. But if you can’t find anything, then calling for plumbing services may be the best option.

Clear any blockage from the pipe

Cleaning blockage from pipes is easy. Simply pour boiling water into the pipe. It shall dissolve any substance inside. Or you can use a wire and put it through the pipe. It will also solve the problem. Try using a strong but flexible wire though, to avoid any hemorrhage to the pipe. 

Clean the clogged vent

You can clean a clogged toilet vent by following the same steps as are mentioned in clearing a clogged drain. Pour vinegar and soda into the vent, and after 30 minutes, use the flush.

Fix or replace damaged or loosened flush valve

If you find out a damaged loosen flash valve, try fixing that by uninstalling and installing it. If this doesn’t work out then you should replace the damaged flash valve as it is resisting proper water flow.

Replace leaking valve

Leaks can sometimes be invisible. They are so small that you can’t find them easily without proper expertise. Try to check every inch of the whole connecting valve. If you find any, try rapping that leakage with waterproof tape.

Take help of plumbing services.

However, after taking utmost care, you may end up finding nothing cause of a lack of expertise. So, you need the experts, i.e., a plumber. He can find any problem in the whole system and get you out of the problem.

Read: Can You Pour Bleach in Toilet Tank?


Normally a toilet tank should fill up immediately after each flush. It’s irritating if you have to wait more than 15 minutes just to fill up your toilet tank. So here we tried to show you all the possible reasons and how to fix them. You may encounter problems beyond these too. You may then seek the help of the experts.

Read: Why Won’t My Toilet Tank Fill up With Water?


How long Should a Toilet Take to Fill?

How to Fix a Slow Filling Toilet Tank
How long should a toilet take to fill

A toilet should take about 2 or 3 minutes to fill up and get ready for the next flush if the valve is open properly. But with a faulty system, a toilet takes 20 minutes to fill, which is unusual.

Is it OK To Put Bleach in The Toilet Tank?

Is it OK to put bleach in the toilet tank
Is it OK to put bleach in the toilet tank

When the question comes if you can pour bleach into the toilet tank, the answer is a big no. because bleach can corrode the internal parts of the toilet tank. It can do damage beyond repair to those parts.

Should you Clean The Inside of your Toilet Tank?

Should you clean the inside of your toilet tank
Should you clean the inside of your toilet tank

Yes, you should clean your toilet tank. It is suggested by experts that you should clean the inside of your toile flash at least twice a year. Cleaning your toilet tank will give you a hygienic and anti-septic environment.

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