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As one of the most worked fixtures in the bathroom, our toilets need to be at their peak performance. But, understandably from time to time, some of us may experience issues when trying to flush the toilet. However, alongside the inconvenience, a toilet that doesn't flush properly can become a source of hygienic issues. 
Fortunately, there are a few common reasons for this problem that can be easily fixed. Here, The Bathroom Showroom identifies some of the most common causes of toilets not flushing properly and helps you solve them.

How Does a Toilet Flush Work?

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A toilet flush operates through a combination of simple mechanics, gravity, and a clever principle of physics known as siphoning. While there are some variations, the basic process for most standard toilets is the same.
The Two Main Sections
A toilet has two primary parts: the tank (or cistern) and the bowl. The flushing action is a synchronized dance between the components in these two sections.
Step 1: Initiating the Flush
When you press the flush handle or button, a lever inside the tank lifts a rubber stopper, known as the flapper. This flapper normally seals the opening at the bottom of the tank, keeping the water inside.
Step 2: Gravity Takes Over
Once the flapper is lifted, gravity takes over. Water stored in the tank rushes into the bowl through the flush valve. This rapid influx is the driving force behind the flush. Water flows through jets around the rim and sometimes a siphon jet at the bottom, rinsing the inner surface.
Step 3: The Siphoning Action
This is the most critical and fascinating part of the process. The toilet bowl has a curved, S-shaped, or P-shaped pipe called the trapway. The trapway is designed to always hold a small amount of water, which acts as a barrier to prevent sewer gases from entering your home.
As the large volume of water from the tank floods the bowl, it quickly raises the water level. This rising water spills over the highest point of the trapway. As it flows down the other side, the weight of the water column in the longer leg of the trapway creates a powerful vacuum, or "siphon effect." This suction force pulls all the water and waste from the bowl, clearing it completely.
Step 4: Refilling the Bowl and Tank
As the water level in the tank drops, the flapper falls back into its sealed position, stopping the flow of water into the bowl. A floating mechanism, which is part of the fill valve, drops with the water level. This action activates the fill valve, which begins to refill the tank with fresh water from your home's water supply.
At the same time, a small refill tube attached to the fill valve sends some water into the overflow tube. This water flows into the toilet bowl and refills it to the proper level. This restores the water barrier in the trapway for the next use.
Step 5: The System Resets
As the water level in the tank rises, the float mechanism rises with it. When the water reaches the predetermined level, the float triggers the fill valve to shut off the water supply. The toilet is now quiet and ready for the next flush.

How Do Toilets Work?

Understanding how our toilets work can help us better figure out solutions to the problems that may occur with them.

How Do I Solve Toilet Flushing Problems?

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When your toilet won't flush, it's often a simple fix you can do yourself. The key is to troubleshoot from the most common and easiest problems to the more complex ones. Here's a step-by-step guide to help you get your toilet working again.
Step 1: Check the Water Supply and Tank
The most basic reason a toilet won't flush is a lack of water.
  • Look in the bowl: Is there water in the toilet bowl?
  • Check the tank: Lift the lid off the toilet tank (cistern) and look inside. Is it full of water? The water level should be about an inch below the top of the overflow tube (the vertical pipe in the center of the tank).
If the tank is empty or has low water: The water supply to the toilet may be turned off. Check the small valve on the water pipe coming out of the wall or floor behind the toilet. Make sure it is fully open.
If the tank fills very slowly or not at all: The fill valve might be clogged or faulty. You may need to clean or replace it.
Step 2: Inspect the Flush Handle and Chain
If the tank is full but nothing happens when you press the handle, the problem is likely with the flushing mechanism itself.
  • Check the handle and chain: Take the lid off the tank and press the flush handle. Watch the chain attached to it. Does it lift the flapper (the rubber stopper at the bottom of the tank)?
If the chain is disconnected: Simply reattach it to the flapper and the lever arm of the handle.
If the chain is too loose: The handle may not be able to lift the flapper high enough. Adjust the chain's length by hooking it to a different link. There should be a small amount of slack, but not so much that it can't lift the flapper.
If the chain is too tight: The flapper may not be sealing properly, causing a constant, slow leak and preventing the tank from refilling. Adjust the chain to give it more slack.
Step 3: Check for a Clog
If the toilet flushes weakly or the water level rises without draining, you likely have a clog.
  • Turn off the water: To prevent a potential overflow, turn off the water supply valve behind the toilet.
  • Use a plunger: Place a sturdy plunger over the drain hole, making sure you have a good seal. Use firm, even, and rapid pushes to create suction and dislodge the blockage.
  • Try a toilet auger: For more stubborn clogs, a toilet auger (or drain snake) is a more effective tool. Insert the coiled cable into the drain and crank the handle to feed it down until it hits the blockage. Once you've broken up the clog, pull the auger out and flush the toilet.
Step 4: Examine the Flapper
If the toilet flushes weakly or runs constantly, a faulty flapper could be the cause.
  • Check for leaks: Drop a few drops of food coloring into the tank. Wait about 15 minutes without flushing. If the water in the bowl changes color, the flapper is leaking.
  • Inspect the flapper: A worn, warped, or damaged flapper will not create a tight seal. Look for cracks or signs of wear.
  • Replace the flapper: A replacement is inexpensive and easy to install. Simply turn off the water, flush the toilet to empty the tank, unclip the old flapper, and install the new one.

When to Call a Professional Plumber

If you've tried all of these steps and the problem persists, it may be a sign of a more serious issue that requires professional help. It's time to call a plumber if:
  • The toilet is still clogged after repeated plunging and snaking.
  • You suspect a blockage deeper in your main sewer line (especially if other drains in your home are slow or gurgle).
  • The flush is weak, and none of the tank adjustments have helped.
  • You notice water on the floor or a leak that you can't locate.
  • There's a broken part inside the tank that you don't feel comfortable replacing.

Act Early To Keep Your Toilet Working Good As New

If you can act on any issues caused by your toilet not flushing correctly as soon as they arise, you can work to prevent significant problems later on. You can also potentially save a lot of time, hassle, and indeed money by solving simple issues such as these mentioned above, by yourself.
But, if you still find you're having problems, it may be worth getting professional help to identify the issue. This will ensure not only do you get your toilet back up and running quickly but also rule out potentially complex issues that may need further investigation here. 
​For more information on creating the perfect space, book an appointment with The Bathroom Showroom. Experts in all things bathrooms, we can help turn your dream bathroom into a reality.