How to Fix a Slow Flushing Toilet

It is hard to be happy when your toilet isn’t flushing properly. Slow or partial flushes leave behind waste and residue that can cause a clog in no time. Moreover, it can be embarrassing and frustrating to constantly warn your guests, “Don’t use that toilet; it won’t flush properly.”

If you have a slow flushing toilet, you need to identify the root of the issue and then figure out the costs of fixing it. Depending on the cause, you might be able to fix it with the tips we’ll be providing today.

Keep reading to find out the best ways how to fix a slow flushing toilet all by yourself.

Toilets 101

Before we start, it is best to refresh your memory on how a toilet works. Toilets are constructed with the basic principle of a gravitational downward flush in mind.

The water tank stores the water that is flushed down the drain. When you hit the flusher, you’re just opening a plug that allows the water to flow down and carry whatever is in the bowl downwards. The water goes deeper into the toilet drain and enters the S-trap, the bend in the drain under the toilet, and finally ends up in the sewer mainline.

What Causes a Slow Flushing Toilet

There are three issues that can cause slow flushing toilets.

  1. There is a hidden clog in the drain. This is the most common issue with slow flushing toilets.
  2. There is a problem with the flushing mechanism, which is the second-most common problem.
  3. The third cause is a mineral buildup that prevents water from flowing.

You can read more about these issues in detail below.

Clogging Issues and Fixes

Toilet clogs or blockages are one of the most common issues you can experience, but they are easy and cheap to fix.

Clogged S-Trap

The S-trap is an S-shaped pipe located under the toilet bowl’s side. The S-trap is a curved pipe; due to the curve, debris and waste may get stuck inside and cause your toilet to lose its game. Clogs like this should be dealt with immediately, or they can cause a sudden overflow that will ruin your bathroom tiles.

The best way to fix this issue is to use a regular old toilet plunger. If your bowl is filled with water, remove it with a bucket or ladle and leave out 2 inches of water. Press the plunger gently over the drain hole and feel if you’ve got a seal. Give it a go with the plunger and plunge upwards to push the clog back.

Using Too Much TP

We are all guilty of using more toilet paper than we actually need; believe it not, this is one of the most common reasons for a clogged toilet. Toilet paper is designed to dissolve in water, but it can leave sticky residue pieces that will stick to the pipes under the toilet. This also depends on the kind of TP you’re using. There are single-layered, double, and triple-layered toilet papers, and thicker ones might be more than your toilet can handle.

Plunging action usually solves the issue, but sometimes the clog might be thick, and you may need a toilet auger or a toilet snake to break it down into smaller pieces. Try your plunger first, but if that doesn’t work, it’s time to buy a toilet auger.

Malfunctioning Parts

While clogs are easy to deal with, replacing parts may require some plumbing skills and tricks. Don’t worry; we’ll be writing about the most common toilet malfunction issues and the best way to deal with them.

Malfunctioning Fill Valve

The tank fill valve is a small valve regulating water refills after you flush the toilet. If you’re unfamiliar with the flushing system, simply google the words toilet flush system and open a picture of a flush system diagram.

To replace the fill valve, you need to shut off the water supply to the toilet from the main valve. Open the water tank by removing the lid on top and flush the toilet to remove the water in the tank. Next, remove the water hose from the flush valve. You need to unscrew the nut that connects them. Next, remove the valve, preferably by pulling it from the base to avoid breaking it, and replace it with the new valve. If you know the make and model of your toilet, you can simply order one online. Once everything is in place, turn the water supply on and flush the toilet. You should be ready to go.

Malfunctioning Overflow Tube

If your toilet doesn’t have enough water in the tank, this will result in slow flushes. Open up the water tank and see what’s going on. The water level should be ½ inch below the overflow tube. If it’s less, then you need to fix it. Take a bucket of water and fill the toilet until it’s ½ inch below the overflow tube. If the toilet flushes as it should, then the overflow tube is at fault. You can replace the overflow tube and keep on flushing.

Mineral Buildup

If the water contains lots of minerals such as magnesium and calcium, your issue might be a mineral build-up around the flush system’s pipes and the toilet bowl’s drain hole. To combat this, simply pour a mix of white vinegar and baking soda into the toilet and in the tube, leave it overnight and flush the toilet in the morning. Things should be back to normal.

Jet Holes Blockage

This one is pretty common for toilets that have been used for a couple of years. When you flush the toilet, the water comes out from these tiny jet holes. They are also called rim holes or inlet holes because they are located under the rim of the toilet. If not regularly cleaned and maintained, they can be clogged with hard water minerals or bacteria and cause a slow flushing toilet.


If bacteria clog the holes, you will see black or orange spots around the jet holes. If that’s the case, you need to brew a concoction to eliminate them and free your toilet from their grasp. The solution should contain one cup of bleach and 10 cups of water. Pour the liquids into the overflow tube, wait around 10 minutes and flush the toilet. After the solution passes through the holes, simply take a piece of wire and a mirror and clean the holes for leftover residue.

The final touch would be to clean the entire underside of the rim with a regular toilet cleaner and see how things stand. The process might have to be repeated a few times for extremely neglected toilets.

If mineral deposits are clogging the holes, you will see white spots and scaly residue. The process is slightly different as you will need to use vinegar instead of bleach. Heat a cup of vinegar to 120 degrees and pour it into the overflow tube. Leave it working for at least an hour, and then hit the flusher. The rest of the process is the same.

You can also watch this helpful video to fix your slow-flushing toilet.

FIX a Weak Flushing TOILET

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