How to clear a blocked drain

Guide written by:
Jeremy, construction site supervisor, Cardiff

Jeremy, construction site supervisor, Cardiff

123 guides

When dealing with a blocked drain, there are a number of solutions to choose from. With the right method and a bit of patience, you'll be able to get rid of the blockage without calling out a professional. From traditional methods to crafty alternatives, read on to find the best way to unclog your drain or plug.

Important features

  • Inspecting the waste trap
  • Flushing with hot water
  • Unblocking a drain using a plunger
  • Unblocking a pipe using a drain snake
  • Unblocking with a chemical drain unblocker
  • Using a drain blaster

How to detect a blocked drain

First of all, let's have a look at the early warning signs of a blocked pipe as it is easier to deal with the issue while the pipe isn't completely blocked and there is still some degree of water drainage:

  • drainage is slower than normal;
  • the drain has started making noises as the water drains;
  • the water level seems to be higher than normal when the sink, toilet or bath is in use.

These are the first signs that indicate there is an issue that needs to be dealt with – and fast! Do not leave the problem for too long as the slower the drainage, the more particles will start to build up in the pipe. This accumulated material will increase the size of the blockage, making it more difficult to get rid of. Here are some of the most commonly affected fixtures and the causes behind the blockages:

  • kitchen sinks:
    • solid food waste,
    • oil and fat,
    • objects like cocktail sticks, mint leaves, herb stalks, etc. ;
  • wash basins, showers and baths:
    • hair,
    • oily residue from bath products, shower gel and shaving foam
    • cotton buds and other solid items
    • sand (in coastal homes);
  • toilets:
    • excessive toilet paper,
    • any other item not suitable for flushing;
  • washing machine drain:
    • a build-up of lint from washed clothes.


  1. Inspecting the waste trap
  2. Flushing with hot water
  3. Unblocking a drain using a plunger
  4. Unblocking a pipe using a drain snake
  5. Clearing a blockage with a chemical drain unblocker
  6. Using a drain blaster

Required skills

Can be carried out by any DIYer (including beginners); no particular skills required.

Completion time

15 to 45 minutes

Number of people required

1 person

Tools and equipment

Select from the following items depending on the unblocking method you have chosen.

Personal protective equipment (PPE)

Please note: this is a non-exhaustive list; be sure to match your personal protective equipment to the job at hand.

1. Inspecting the waste trap

Before attempting to unblock the drain, you will have to check the waste trap. The purpose of the waste trap is to catch any solid material before it reaches your pipes.
  • Start by emptying the water from your sanitaryware.
  • Next, place a container beneath the waste trap and unscrew it by hand. Usually, the build-up will be found in the trap body. In this case, you simply have to remove the material to solve the issue of your blocked pipes.
  • Screw the trap body back into place and let the water run. If the problem has not been resolved, you will have to proceed to one of the methods listed below.

2. Flushing with hot water

This method involves boiling water and pouring it down your drain. The heat will help to turn any greasy food waste or soap residue into liquid. This is a good option for kitchen sinks, wash basins, showers and baths.

  • Start by filling up your kettle to its maximum level.
  • Bail out any cold water that is stuck in your fixture.
  • Pour down the hot water.

3. Unblocking a drain using a plunger

When using a plunger, you don't have to remove any water that is stuck in your sink, toilet or bath. You simply need to:

  • position the plunger over the drain and plunge in an up-and-down motion;
  • keep plunging in and out until the blockage starts to move. It should then be driven down and drained away.

Plungers can be used on kitchen sinkswash basinsshowersbaths and toilets.

4. Using a drain snake to unblock a drain pipe

A drain snake, or drain auger, is a flexible metal cable equipped a long spring. These tools have a spiralled end on one side (for piercing through a blockage) and a handle on the other (for turning the tool).

  • Before you use a drain snake, you will have to remove your waste trap in order to open up the pipe and insert the tool – that is, unless your pipe is fitted with an access cover.
  • Turn the handle to allow the drain snake to work its way along the pipe in a rotating motion, pushing the blockage as it goes.

5. Unblocking with a chemical unblocker

Chemical unblockers are usually made using caustic soda and can be in liquid or granule form. They work to dissolve any organic material such as hair, soap build-up or any other greasy substance. This method does have its drawbacks – most importantly, in terms of user safety.

You will have to protect your skin and eyes when using these products. Chemical products are also harmful for the environment. Before using a chemical unblocker, you must read all safety notices and remove as much stagnant water from your sanitaryware as possible.

Pour the unblocker into the drain and simply wait for the product to take effect and break down any foreign objects blocking your pipes. This should take around 30 minutes. These types of products do generate heat and release harmful gases, and must be used with caution. Chemical drain unblockers are suitable for kitchen sinkswash basinsshowers and baths.

6. Using a drain blaster

These long, cylindrical tools are equipped with a spring and a suction cup. The spring is used to hold the cup in place until the trigger is pressed. You simply need to grab your 'weapon', position it over the drain and press the trigger.

The suction cup is released instantly, sending a blast of pressure to the blockage to drive it down your drain pipe. You can find smaller models designed for wash basins, kitchen sinks showers and baths, as well as larger models for blocked toilets.

The idea behind a drain blaster is similar to a traditional plunger with the addition of the 'shock wave' effect produced by the suction cup.

5 crafty DIY tricks for unblocking your drains

   1. Flush a white vinegar and bicarbonate of soda mixture

This is a good, environmentally friendly alternative to chemical unblocking with a specialist product.

Create your mixture by combining 200 g of bicarbonate of soda with 200 ml of white vinegar. The mixture will work to break down your blockage.

   2. Use an unbent metal coat hanger

A good option if you do not have a drain snake or if you have a waste trap that cannot be removed – which can be the case with some shower drain.

Straighten out a wire coat hanger, shape one end to form a small hook and insert it into your drain to reach the blockage.

   3. Clear the blockage with a vacuum cleaner

Unless you have a wet-dry vacuum cleaner, take special care to empty your waste trap before attempting this method to ensure you are only sucking up air and (of course) the blockage. Remember: ordinary vacuum cleaners do not mix well with water!

Insert the vacuum hose into the drain to move the blockage along and unclog the drain.

This method works in a similar way to using a plunger.

   4. Inserting a garden hose

Insert a garden hose as far as possible into the blocked drain and turn on the water.

This process is based on a professional method called hydro cleansing.

   5. Cover your hand with a bin bag and reach into the drain

This solution is suitable for blocked toilets.

If the blockage is in the toilet waste trap, reach into the toilet bowl with your arm covered in a bin bag. Insert your hand under the water and into the drain hole to clear the blockage.

Using a number of methods

By this point, you have a range of methods to choose from – but which is the best solution?

While your decision will depend on the nature of the blockage and the situation at hand, the most effective solution is usually to combine a number of methods. For example, when unclogging a kitchen sink:

  • start by removing as much material as possible from the drain;
  • pour down a vinegar and bicarbonate of soda solution;
  • leave the mixture to work for 15 minutes;
  • pour down some hot water and use a plunger to clear the blockage.

By combining different techniques, you will maximise your chances of success – and earn your first plumbing stripes in the process!

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Guide written by:

Jeremy, construction site supervisor, Cardiff 123 guides écrits

Jeremy, construction site supervisor, Cardiff

I'm a trained electrician who started off working in large-scale industrial projects. Most of my early career was spent taking on huge electrical installations. I like to think that no job is too big for me, and after all the experience I'd gained, I started managing teams of electricians.

I like to learn on the job, so around ten years ago, I moved into building and construction. As a site manager, I've overseen the building of small residences, sport facilities, and even theatres!

Working with my hands is something I love to do in my free time as well. For four years now, I've been restoring our home in the Welsh countryside. I even built a conservatory for my wife, who loves watching the sheep behind our house.

Whether it's patios, interior design, roofing, plumbing or electricity - I love giving it all a go! I've even made my family DIY converts and together we've built almost everything we have from scratch. My experience, both in the field and in my workshop, has taught me a lot and I'm happy to share what I've learned. No matter how big or small your project is, I'm here to answer your questions and help you choose the right tools and equipment.

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