Reasons for Slow Flushing Toilet and How to Unclog a Slow Draining Toilet

You are used to hearing your toilet give a loud roar each time you flush it, but there are days when you only hear a slight whimper along with water rising before your toilet slowly drains, right? If that happens, it only indicates that your toilet is clogged and requires the services of an emergency plumber or if you have the tools and the technical know-how, you can DIY a slow draining toilet.

We recommend that you perform a slow draining toilet fix to prevent water wastage. Also, if you wait too long, the issue of unclogged toilet will only worsen to the point that it can cause indoor flooding. That’s more expenses!

What Is The Importance Of A Fast Flush?

To understand why you should bother to know if your toilet flushes fast, you must know how a toilet works. Each time you flush your toilet, the flushing action prompts a stream of water from the tank to the toilet bowl before the water travels down to the main waste water line. The rate with which the water travels generate the suction that is required for the flush. The slower the movement of the water is, the less effective the flush is. In time, this problem creates a larger problem in your home.

Slow Flushing Toilet Causes

Before we delve into the issue of slow draining toilet fix, let us first understand why your toilet is draining slow so we can target the exact cure on how to unclog a slow draining toilet. Here are the possible reasons:

1. The water level in the toilet tank is low

When you have a clogged toilet, the first thing you want to do is to inspect the toilet tank. Simply remove the lid and place it in a safe place to avoid damaging it. Then check the water level.

If the water level appears lower than it should be, then the problem is your toilet tank. If there is not enough water in the toilet tank, there is little force during the flushing action. This is the reason for a slow drawing toilet.

2.   Drain blockage or buildup

Studies have shown that every year, one out of five households deals with the problem of a blocked drainage system. For some households, the problem could just be simple but for some, the blockage could be due to a system that is more complicated and harder to fix.

So, how do you determine if the problem is due to a drain buildup? One way to know is by using a gallon of water. Pour one gallon of water into the toilet bowl. If the water rises quickly, the problem is a clogged drain.

But, if the water recedes or stays the same, then the issue of the slow draining toilet could be caused by the toilet tank.

3.   Mineral or sediment buildup

Those households that use hard water are more prone to get this issue. The mineral buildup clogs the jet holes which are responsible for producing a strong flush. Either the mineral or the sediment buildup along the side of the jet holes gradually reduces water pressure each time the toilet is flushed.

4.   Broken flush mechanism

One of the slow flushing toilet causes is a broken flush. It is either the flush handle is broken or too tight. It also possible that the flush handle is too loose that is why you are having an issue with a slow draining toilet.

5.  Broken flapper valve

There is an apparatus called a flapper valve found in the toilet tank. Each time you flush the toilet, the flapper valve opens and stops the flow of water. Over time, the flapper valve may get broken as a result of wear and tear.

6.  Poor venting

Do you see that small and open pipe found on your roof? That is called the vent stack for the sewage. This open pipe allows the air to move through the plumbing so the water can flow downwards.

Gases and smells from your toilet are also released from this vent stack. And, since it is located outside of your home, issues like birds building their nests on the vent happens. This restricts the movement of air. If there is an obstruction in the vent stack like the bird’s nest, it could be one of the slow flushing toilet causes.

Slow Draining Toilet Fix

If you are bent on slow draining toilet fix DIY, these are the things that you need to know in order to be successful in your project of slow flushing toilet fix.

1. To fix broken fill tube

This is a small apparatus but serves a very important role in the interior of your toilet tank. It is usually made of rubber and it is color black. The fill tube leads into a large vertical tube called the overflow tube.

Each time you flush, the fill tube transfers water from the toilet tank to the toilet bowl. Over time, the fill tube becomes damaged and when this happens, the toilet tank gets filled with water that slowly drains.

If you see that the tube is only disconnected and is still in good condition, all you need to do is attach the fill tube to the cylinder. But, if it is damaged, you need to get a replacement like the Fluidmaster 400AH PerforMAX Universal High Performance Toilet Fill Valve.

2.   To fix low water tank level

If the toilet tank does not replenish itself to the correct level, you may want to solve the slow draining toilet issue by changing the float level to allow for a higher water fill.

3.  To fix pipe obstruction

If you experience a slow draining toilet but it is not clogged, the first thing that comes to your mind is to use the plunger. Most of the time, that is correct. If there is an obstruction, it is one of the reasons for slow flushing toilet causes. A plunger can remove the obstruction or you can use a toilet auger snake.

Not sure which to buy? The light duty toilet auger 3 foot length for household toilets is one of our recommendations.

Another way to unclog a toilet bowl is by using dishwashing soap and a drain cleaner. The first step is to pour a gallon of hot water onto the toilet bowl. Wait for a few minutes. Then, apply a small amount of toilet bowl drain clean agent. Depending on the manufacturer’s instruction, either you flush right away or wait for a few minutes.

Then, take off the toilet tank’s lid. Look for the overflow pipe and then apply a tablespoon of the liquid dishwashing detergent and allow to sit for about ten minutes. This process will remove all the deposits that cause slow draining toilet. After ten minutes, you can now flush your toilet.

4.  To fix mineral or sediment buildup

If the buildup is already in its advanced stage, the float will close earlier than it should be. If this is the case, all you have to do is to clean the area to remove all the mineral or sediment buildup.

Apart from cleaning, you may also have to replace some toilet tank parts like the flapper. Good thing, you do not have to spend a fortune for a flapper replacement. One of the reasonably priced yet very effective is the Fluidmaster 400CR Universal toilet flapper repair kit.

5.   To fix the flushing mechanism

Open the toilet bowl and inspect the flapper. If it is not sealing well, or if the chain that is connected to the flapper is damaged, it results to slow draining toilet. If the flapper is not yet broken, all you need to do is to adjust it for a tighter seal. Otherwise, you may have to purchase a new flapper for the flushing action to be more effective. Or, you may also need to replace the flushing mechanism itself. Try the DANCO toilet handle replacement which is made from durable metal and is corrosion resistant.

6.   To fix the blocked sewer vent

To do a slow draining toilet fix regarding this problem, an extra effort is required on your part and that is going on top of your roof. See if there are blockages like bird’s nests and dried leaves. Make sure you have a flashlight with you because if you do not see any blockage, you would have to look deeper into the sewer vent. This is because the blockage could be too far down the pipe. If you can reach it by using a plumber’s snake, well and good. If not, you need a plumber to dislodge it for a slow draining toilet fix.

7.  Time to change a broken toilet bowl

Though this issue is not as common compared to a broken fill tube, but, it happens. You may not notice it but there could already a crack on the lower boil that causes water leakage. You may apply a seal but this is only temporary. The best thing to do is to replace your toilet bowl.

Now, if you are unsuccessful in your DIY slow draining toilet fix, it is time to call your neighborhood emergency plumber.

When To Call An Emergency Plumber for Slow Draining Toilet?

If, after using the plunger or the toilet auger snake, your toilet remains the same, then that is the time to call for help.

You may not be aware but the problem could stem from something deeper. Only a professional plumber has the tools and knowledge that can find the main cause of a clogged toilet. A simple clog may already be a sign of a bigger problem. So, to avoid the problem of indoor flooding and other unsanitary issues, it is best to seek the help of an emergency plumber for a slow flushing toilet fix.


If you are troubled by a slow draining toilet, the causes can be clogging or it could be that it is time for you to change some of the apparatus in the toilet tank. It is best to look into the slow flushing toilet causes so you can decipher if you can handle a slow draining toilet fix. If not, get that phone of yours ready and call an emergency plumber.

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