Why is My Toilet Flushing Slow: Slow Flushing Toilet Causes and Fixes

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It’s the moment of truth. You walk into the bathroom, do your business, and then it’s time to flush. But for some reason, the toilet just doesn’t seem to be working properly. Maybe it’s taking forever to flush, or maybe it’s not flushing at all. What could be causing this problem? And more importantly, how can you fix it?

Did you know that a toilet is one of the most used appliances in your home? And unfortunately, it’s also one of the most common sources of household problems. One of the most common issues with toilets is slow flushing.

In this blog post, we’re going to show you what can cause a slow flushing toilet and how to fix it. We’ll also give you some tips on how to prevent these problems from happening in the first place!

How Does A Toilet Work?

Before we get into the different causes of slow flushing toilets, it might be helpful to understand a little bit about how toilets work.

These toilets are also known as Gravity Toilets and that is exactly how they work. Essentially a tank is connected to your home’s water supply through a pipe called the “supply line.” When you flush the toilet, a valve opens and water flows from the tank into the toilet bowl. This water flushes the toilet bowl and pushes the waste down the “drain line.”

The drain line is connected to your home’s sewer system (or septic tank). As the water flows down the drain line, it also pushes the waste with it. Once the toilet tank is empty, a new flush cycle can begin.

How To Identify A Slow Flushing Toilet

When it comes to identifying a slow flushing toilet, there are many different causes. It makes sense to educate yourself on what might be causing the problem before attempting to fix it. Essentially there are 3 primary causes for this slow down in your toilet flushing.

  1. Slow flushing toilet caused by a blockage
  2. Slow flushing toilet caused by water problems
  3. Slow flushing toilet caused by malfunction of equipment

Slow Flushing Toilet Caused By A Blockage

This is possibly the most common reason for a slow-flushing toilet in most homes. The toilet bowl may be draining slowly due to a build-up of material in the drains.

Over time, hair, toilet paper, and other materials can accumulate in your s-trap (see diagram 1.1) and cause a clog. This build-up will eventually slow down the flow of water and waste through the drain lines.

How Can I Unclog The Blockage?

This is a very easy fix and will require the use of a plunger. Make sure the plunger covers the bottom of the toilet bowl, and once in place, start to pump the plunger, causing a vacuum and releasing the blocked items. Have a plastic bag handy to put all the debris that comes out.

A top tip is to install a jet gun to wash your behind, which is not only more healthy but eliminates the toilet paper blockage issue forever and will save you money in toilet paper costs.

Slow Flushing Toilet Caused By Water Problems

Essentially there are a couple of problems where water is responsible for a slow flushing toilet and they are as follows:

Hard Water

Hard water issues are increasing in the US, and if not resolved early on, they can not only be extremely inconvenient, they can be expensive down the line.

Hard water has a high mineral content like magnesium and calcium, and a good way to tell if you have hard water is to check for white water marks that look like dried salt stains around your sink area. Accumulation of these minerals within the pipes will not only make water harder to flow but will also make the pipes more susceptible to corrosion.

How To Remove Mineral Build-up From The Pipes

Mineral build-up in the pipes can be easily cleaned. Shut the water supply to the tank off and lift the toilet flapper that covers the drain and pour half a gallon of white vinegar directly into the tube, and leave overnight for the vinegar to eat away at the mineral build-up.

The next morning turn the water back on and let the tank fill up and flush the toilet a couple of times. This should clean out the pipe. You may need to repeat the process for another night if the deposit is stubborn.

Lack Of Water

If you find that, over time, your toilet has lost its power to flush, then the first thing to check is if there is enough water inside the tank. The tank should be almost full of water with only around 1/2 to 1-inch space left under the overflow pipe.

How To Fix A Lack Of Water Problem

Well, the simple answer is to fill up the tank manually using a bucket or a hose pipe. This will resolve the issue temporarily. However, the problem may lie in the filling valve or the float mechanism, which will most likely need to be replaced if the problem persists.

Slow Flushing Toilet Caused By Malfunction Of Equipment

There are quite a few moving parts in a tank toilet and over time these parts will fail due to wear and tear and will require your attention.

Fill Valve, Float, or Toilet Flapper

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A fill valve is where the water comes out, so you will need to close the water and empty the tank by flushing it. Once empty, detach the hose that is connected to the fill valve by loosening the bolt that holds them together.

You can now remove and replace the fill valve with a new one. Reattach the hose and turn your water back on.


A float is a part that controls the amount of water that enters the tank by floating up as the water fills up and eventually shutting off the water supply.

The float is held on via a rod to which it is threaded on. This float, if damaged, can be screwed off and replaced by a new one quite easily.


The toilet flapper sits on top of the drain via pegs and stops the water from constantly flowing into the bowl. You will need to measure the flapper to make sure you have the correct size or remove it and take it to your hardware store for an exact match.

Once again, turn off the water first and flush the toilet. Remove the chain that connects the flapper to the handle first and then gently pull the flapper, releasing the pegs from their holes. Place the new flapper in place and push the pegs into their respective positions, securing the flapper.

It’s important to note that when these parts fail, it can drive your water bills up quite considerably, so either repairing or replacing them should be a priority.

Jammed Up Toilet Rim Jet

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These jets tend to get obstructed by dirt and mineral deposits over time, and this results in bacteria build-up. The rim jets are what make sure your toilet performs its flushing duties with flair.

They angle the water flow in such a way that it creates an effective circular motion, which is key for a powerful cleansing flush.

How To Clean Toilet Rim Jet

Using a small mirror inspect the jets to see if you have limescale build-up and/or bacteria over the jets. Mix 1 part bleach and 10 parts water to clean off and kill the bacteria with a brush. Make sure to wear gloves, goggles, and a face mask. The limescale or mineral build-up should be removed using 2 methods.

Vinegar eats through limescale and works best when heated to around 120 degrees Fahrenheit. Pour the vinegar through the overflow pipe and leave for 1 hour. Meanwhile, get a brush and a scouring pad and scrub the jet holes until they are properly soaked with vinegar. Grab a wire and start to dig out any dirt or build-up within the jets.

After an hour, flush the toilet and be ready to see some muck come through. You may need to repeat this process a couple of times to completely clean the jets out.

Frequently Asked Questions (FAQs)

Can you use vinegar to unclog a toilet?

Vinegar is not only great for unclogging toilets, but it is also environmentally friendly and safe for your family and pets. Simply heat the vinegar to around 120 degrees Fahrenheit and pour it onto or through the pipes to release any residue build-up.

Why is my toilet flush not powerful?

If your toilet is not working the way it should, then it is probably due to blockages in the rim jets in the bowl, and the waste pipe due to mineral build-up, or the tank is not filling up to the required amount of water resulting in a weak flush.

Why won’t my toilet fill up with water after I flush?

This will generally be because of a number of things. The fill valve has become faulty, the toilet float needs to be adjusted or replaced, the overflow tube has a crack, the toilet flapper is not sitting properly, and water is leaking.

Why is my toilet bowl empty?

If your water pressure is high, then this can cause your toilet to flush, or if the flapper has worn out, causing an accidental flush, and if the drainage setup is incorrectly aired, it can cause back-siphonage emptying the bowl randomly.

Can I pour water into my toilet tank?

That is the simple solution to a tank not filling up with water. Take a bucket or a hose pipe and fill it up just below the overflow and flush your toilet.

Why is my toilet bubbling or gurgling?

This is generally caused by negative air pressure in the drain pipes. There is a blockage, and the pressure is causing the debris to push back instead of flowing out, resulting in bubbling and gurgling sounds.

The easiest way to fix this is by using a plunger to free up the blocked debris. We have a detailed article here on the cause and fixes here.


Having a normally functioning toilet is sometimes taken for granted. You walk in, do your business and push the button or pull the lever after, and all is good. 

It’s only when things don’t work properly do we realize the importance of a properly working toilet. We hope that we were able to show why your toilet is flushing slowly and how to address the issue. 

Most of the fixes are pretty simple and can be dealt with by yourself, but if you are not sure, then it may be an idea to get some professional help and avoid any mishaps!

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