How to Fix a Toilet Flush

Whether your toilet’s flush is weak, not working at all, or running constantly, it’s probably a fix that can be done yourself. The flushing mechanism is made up of multiple parts, and if one of these gets damaged or worn down, it can affect how the whole system works. Thankfully, most problems can be resolved by just replacing one of these parts, which is a job that can take just a few minutes. Below we’ve outlined some of the different problems that might occur with your toilet flush system, what’s causing them, and how to fix them.

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A toilet flush can fail due to worn or faulty parts such as the flush button/lever, flapper, flush valve, or fill valve, often leading to weak flushing, constant running, or no flush at all.
Most toilet flush issues are easy DIY fixes. Start by inspecting the mechanism, identify the damaged or faulty component, and simply replace or adjust it. After repairs, reassemble the cistern and test the flush. If problems persist, it’s best to call a plumber.

How does a toilet flush work?

Before fixing your toilet flush, it’s a good idea to understand how it works in the first place. A flush mechanism requires multiple moving parts to do its job:

Flush handle or button
Flapper
Flush valve
Fill valve

These then all work together to make your toilet flush. When you pull the handle or press the toilet flush button, the flapper inside the cistern lifts up, opening the flush valve. This allows water to be released into the toilet bowl. The water originally in the bowl is flushed out, and the newly released water fills the bowl, siphoning out the old water and waste. The flapper then closes, and the fill valve fills the tank back up with water so you can flush again if needed.

Why won’t my toilet flush?

There are a few reasons that cause a toilet to not flush properly:

A loose or faulty flush button/lever will prevent the toilet from flushing at all.
A damaged flapper may result in your toilet running constantly.
A faulty flush valve can result in leaks, inconsistent or weak flushing, and low water levels in the cistern.
A damaged fill valve may stop the tank from refilling properly. This can also be the problem if you’ve noticed your toilet has a low water level. Insufficient water levels in the tank can lead to a weak flush.

How to fix a toilet flush

Once you’ve found out that the flushing mechanism is the reason your toilet isn’t flushing properly, you’ll need to fix it. But don’t worry, we’ve put together our advice on guidance on getting the job done.

Adjustable wrench
Replacement parts
Plunger or toilet auger
Screwdrivers (both Philips and flathead)
Bucket
Towels
Lubricant

Remove the lid from the cistern and turn off the water supply. To do this, you’ll need to turn off the isolation valve on the water pipe leading into the cistern.

Drain the system by siphoning water from the bowl and absorbing any remaining water with a sponge.

Cover the area with towels in case of leaks or spills.

Faulty parts can be the main cause of issues with a toilet flush. Here’s how to inspect them:

If the toilet has a weak flush, check the toilet flush valve. If the weak flush is due to a low water level, check the fill valve.

If your toilet won’t flush at all, check the valves, make sure the chain isn’t broken or disconnected, and check the flush lever or button.

If the toilet is constantly flushing, check the flapper or flush valve.

Some of these issues will simply need a part to be replaced, and this can just take a few minutes. Replacement parts will also come with instructions on how to install them.

Sometimes fixing the issue can be even less of a task than this. For example, if your flush lever or button is stuck (not broken), it may only need a little bit of lubrication or adjustment to function as normal.

Once you’ve replaced or repaired your faulty part, you can put everything back together, making sure it’s properly secure. Then turn the water back on and do a test flush to see if your fix has sorted the problem. If the issue persists, this is when you should call in a plumber.

Fixing a toilet flush may be a job you considered calling a plumber in for, but you can easily fix the issue yourself. Once you’ve worked out what’s causing the problem, you should be able to replace any damaged parts or make some adjustments to get it back into working order. If your DIY repairs don’t do the trick, that’s when you may need to call in the professionals.

If you’re currently crossing off a few simple maintenance tasks in your bathroom, check out our guide on how to fix a dripping shower head.

FAQs

A damaged fill valve may stop the tank from refilling properly which can result in your toilet having a low water level. This means you may just need to replace the fill valve to fix this problem.

To manually flush a toilet when it’s not working, you can lift the flap inside the tank or pour a bucket of water into the toilet bowl to force the waste through the siphoning system. These are temporary solutions until the cause of the problem is fixed.

You’ll need to use a plunger to create a tight seal over the drain before pushing firmly several times. If this still doesn’t work, try pouring some hot water and some dish soap into the bowl to loosen the blockage before plunging again.