Unblocking A Blocked Toilet

blocked toilet


This post describes: How to clear a blocked toilet and includes how to remove the trap water so it can safely be disconnected from the sewer without spilling anything.

As you can see I’ve censored the featured image for this post. I decided somethings are best left to the imagination. Imagine the water level is just below the level you can see and you will have the picture.


I had to help an elderly neighbour the other day when they reported a blocked toilet to me. I’ve unblocked the occasional blocked toilet over the years. I can assure you I don’t like making a mess or getting dirty in the process.

Another thing I’ve done with toilets is remove the water from the built in trap. I’ve done it so I can disconnect them without spilling the trap water when they are moved.

Both of these things can be done using similar methods with the same tool.

“This operation can involve coming into contact with sewage. So be warned and be prepared.” — HC

Health & Safety

Pic. 1. 100 Years of ROSPA
rospa blocked toilets

I worked all my life for a company who regularly delivered ROSPA leaflets to the workforce. The company had very high safety standards with special booklets given to all engineering staff from day one. This was in the 1960’s well before the modern ‘Health & Safety Brigade’ entered the scene. So to me Health & Safety just makes good sense.

If you are working with sewage you need to take special care not to catch diseases contained in it. Diseases that can be caught from raw sewage include:

If you are going to make the sewage splash you should protect your:

  • hands with rubber gloves,
  • eyes with goggles,
  • mouth with a face mask,
  • clothes, body and arms with an overall or boiler suit,
  • feet with waterproof shoes, wellingtons or waders,
  • head with a hat, helmet or hood attached to the overall.

Examining And Clearing A Blocked Toilet

When someone asks me to unblock a blocked toilet I don’t know exactly what I will find but I assume it won’t be pleasant.

I could find:

  1. a visible blockage where I can see the item restricting the flow. It could be a mobile phone or a bar of soap,
  2. an invisible blockage where a partially blocked toilet looks normal with clear water in the trap,
  3. a blocked toilet pan full to the top with dirty water through which I cannot see.

It is helpful if the person who “owns” the blockage advises me what the cause might be.

NOTE: With the blockages I have seen It’s always been the case that one full flush of the cistern has just about filled the closet pan. The good thing is: I’ve never known one overflow the pan and pour out on the floor with just one flush. The other good thing I have noticed is: Blockages always leak away. So a full pan will empty itself given sufficient time. Successive flushing may clear a blocked toilet. If not try other methods.


Removing A Foreign Body From A Blocked Toilet

A visible item (as in 1 above) can be removed by taking hold of it while wearing rubber gloves and putting it in a bucket to transport it out of the building. I would place an old rag or towel on the floor between the toilet and the bucket to catch the drips and keep the floor clean.

If it were a mobile phone (as in 2 above) it could be jammed in the bend of the trap. I would then have to remove it by disconnecting the toilet so I could poke it back out of the trap from the back.

Clearing A Toilet Blocked By Normal Use

Toilets blocked with their normal contents often look like 3 above. Too much toilet paper coming together in the trap to form a bung. If the blockage is at the mouth of the trap I may be able to brake it up with a thin stick like a garden cane.

So often a bung of paper moves deep into the trap where it can’t be reached with a stick.

Using Hot Water And Detergent Or Liquid Soap To Clear A Blockage

A friend of mine recently told me he had cleared a blocked toilet at his workplace. He did it by pouring half a bottle of liquid soap into the toilet followed by hot water from an adjacent shower. He left it to dissolve the blockage and it eventually gave way enough for him to flush it clear.

I suspect various common detergents would have worked as well. The water should only be hand hot so as not to crack the porcelain of the toilet pan.

I think he had a good idea. I might try it next time.

Using Plungers To Clear A Blockage

A blockage can be pushed through the trap using a high pressure hose or a flexible rod. So far I’ve found it can be done using hydraulic pressure from a plunger.

A plunger is a stick with a rubber cup on one end for placing over the mouth of the trap. Pressure applied by the plunger acts directly on the bung. A few pushes back and forth with a plunger can soon do the trick.

Choosing the correct plunger helps if you want to do a good job. Here are the two basic types:

Pic. 2. Plungers
blocked toilet
Pic. 2. Top: A Toilet (Flange) plunger. Bottom: A Sink (Cup) Plunger.

You can clearly see which plunger to use on a blocked toilet. It’s a Flange Plunger whose cup is moulded to fit in the mouth of a toilet trap.

The sink plunger (called a Cup Plunger) fits better over the waste hole in a basin, sink, bath or shower.

Pushing the handle puts pressure on the rubber cup at the end to change its shape and reduce its volume. The action creates air or water pressure. This pushes water through the waste hole or trap to put pressure on the blockage. The pressure exerted on the blockage pushes it further down the pipe. Hopefully it will disintegrate in the process and wash away through a wider section of pipe following the trap.

Need a plunger? Check this list.

Making A Simple Plunger

In the absence of a rubber plunger I can soon make one. I had to do that recently when I helped my friend. The parts I used were:

  • a 25mm × 25mm × 600mm piece of timber,
  • some old rags,
  • some duct tape,
  • a water tight plastic bag to cover the rags.

The method of construction was:

  1. form the rags into a ball 100mm in diameter,
  2. tape the rag ball to one end of the timber with duct tape,
  3. cover the rag ball and that end of the timber with the plastic bag and bind around it to hold the bag to the timber with a watertight seal.

If the rags get wet with sewage then you will have another mess to deal with.

You can see mine below:

Pic. 3. A Home-made Plunger
blocked toilet
Pic. 3. A Home-made Plunger

Using A Plunger To Empty A Trap

Removing the toilet gives access to the outlet but it needs emptying first.

This is how to empty it:

Make the water move in and out of the trap with a simple soft plunger. Move it back and forth into the mouth of the trap with a suitable rhythm. Each time it’s pushed down the water moves into the trap. Some shoots through the trap and out the other side and down the sewer pipe never to return. Continuing this action removes more and more water until the trap is empty.

Disconnecting A Close Coupled Toilet

A close coupled toilet is one with the cistern resting on the back of the closet pan without a visible gap between them. You should find the cistern and closet pan bolted together so they can be moved around together.

How to disconnect a close coupled toilet:

  1. Disconnect the fill pipe and overflow pipe from the cistern.
  2. Unbolt the cistern from the wall. There are often two screws inside the cistern near the top.
  3. Unbolt the closet pan from the floor.
  4. Pull the closet pan to unplug it from the sewer pipe connector.

Reconnection is the reversal of this procedure.

After Removing The Blockage

Destroying or loosening the bung will let the effluent rush away. Several following flushes will then clear the pan and pipes of debris.

The trap is the narrowest section of pipe that the effluent has to pass through on its journey. The pipes beyond the trap get larger in diameter allowing easier movement as it moves toward the main sewer.

Other Problematic Sections

Bends and Adapters

Closet pans often plug into connectors with nasty bends in them. The bends help to get the toilet in the correct position. These bends may direct the effluent horizontally or at worst vertically upwards. Some of the adapters that connect toilets to the main 100mm soil pipework have a larger diameter within them. Their outlets then narrow down to 100mm. Effluent solids in these sections may stagnate if not followed by plenty of flushing water to keep them clear.

Inspection Chambers

I had to regularly clear blockages from an inspection chamber at my parents’ house many years ago. They had the waste from a new 1st floor (level two) bathroom connected into an existing sewer pipe, connecting the outside toilet to the sewer, via a new inspection chamber.

The outside toilet waste passed straight through the “y” access junction used to connect the upstairs bathroom. The bathroom effluent would descend at speed and hit the main pipe run in the chamber at an the wrong angle only to pile up on the side benching.

The pile would grow over time and eventually collapse into the open pipe section forming a plug when washed into the inspection chamber’s exit pipe. Effluent would then build up behind this blockage until the inspection chamber filled and the effluent leaked out around the cover.

Clearing the blockage was difficult in the murky water. Rodding out the exit pipe cleared it.

It took a couple of years or more to work out:

  1. the cause, discovered by flushing paper down to the inspection chamber while watching it.
  2. the solution which was to build up the benching on the opposite side to the inlet with extra mortar. This stopped the effluent mounting the benching and forced each and very flush to continue into the exit pipe.

Know Your Property

People should know the difficulties of plumbing toilets into their property. When aware of any awkward bends and adapters fitted they can then guard against blockages in those toilets.

Right-angled couplings which go straight down into the ground are not usually a problem. I’m sure gravity keeps them clear.

Avoid Blockages During Drought Conditions

In a drought water supply companies may advocate a reduction of the water flushed down toilets. This may be fine if a toilet has a straight connection. If not then awkward right-angled bends and connection adapters may need plenty of flushing water to keep them clear.

Further Reading

See my post Unblocking My Wash Basin Drain.


Author: Helpful Colin

I have a background in telecommunications and a fascination with all things scientific and technical - from physics to electronics, and computing to DIY.

2 thoughts on “Unblocking A Blocked Toilet”

  1. Colin – this makeshift make your own DIY plunger really worked, thank you for the directions/suggestion! Worked in a pinch when we didn’t want to go out and purchase a plunger. Took me longer to make the plunger than to unclog the toilet…

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