How to unclog a drain with a plunger

Plunging to unblock a drain, sink or toilet is one of those jobs you should avoid doing unless you know how.

Here is a simple guide to plunging like a professional.

How do these plungers actually work?

Used correctly, a plunger changes the pressure in a clogged drain and creates a vacuum.

When the plunger is moved up and down, the blockage may break down from the pressure or more likely, is forced to move along the drain. If it is free to move it can then be flushed away.

Sound easy? The catch is if your plunging technique is inadequate, the clog can just move further down the drain and can become impossible to flush away. That’s when things can escalate from bad to worse.

So what’s the trick to unclogging your drain?

Use the right plunger for the job

A plunger is often a bathroom staple, but are you using the right one for the job? The standard plunger, called a cup plunger, is a rimmed cup of rubber on the end of a blunt shaft, which is designed to create a seal on a flat surface.

Plungers work best on a wet surface.

On the other hand, a blocked toilet needs a flange or funnel plunger. This looks a bit like a stubby mushroom on the end of a shaft and it is designed to work on the curved surface of a toilet.

You need to make sure you purchase your plunger from a specialty plumbing supplies shop rather than a hardware store to ensure you get a good quality one.

Apply heat

Prepare your plunger by running it under hot water to make it more pliant. Also add hot water and a squirt of detergent to the sink or toilet and wait a few minutes.

This improves the suction as plungers work best on a wet surface.

Guard against overflows or spills

Only try plunging if you have not already tried using a Bio-Clean treatment to clear the blockage.

As there’s a high probability of spillage when you use a plunger, you’ll need to cover or stuff the overflow drain in the floor with a towel or cloth to create a seal, if you are plunging the sink or bath.

If you’re plunging to clear a toilet blockage you will need to place a towel on the floor for any spills and turn off the tap at the isolation valve on the wall.

A word of advice for the brave: wear gloves and empty the toilet before you begin.

Plunging technique for sinks and drains

To unblock sinks, baths or showers, use a cup plunger:

  1. Have the water level ideally above the plunger cup – the toilet or sink should be about half full. If it’s a shower, use the plunger to act as the plug then fill the shower base as much as you can. Place the plunger over the blocked drain so that it completely covers the opening.
  2. Push down until the bowl of the cup touches the drain and then pull up quickly, taking care not to break the suction. Apply equal pressure to both the push and the pull.
  3. Repeat the push-pull action a few times. You may feel the blockage dislodge.
  4. On your final pull, draw the plunger up sharply to break the seal.
  5. If the sink/shower is clear you’ll see and hear the water that was sitting on top of the blockage drain away.
  6. Repeat if necessary. If the blockage remains, you should definitely call a plumber.

Plunging technique for toilets

To unblock a toilet, use a flange/funnel plunger:

  1. Place an old towel on the floor to absorb any spills.
  2. To stop the toilet from overflowing, turn off the water at the isolation valve, which is where water enters the cistern (it is often located near the cistern).
    If the toilet bowl is full, don some gloves and remove material from the toilet until it is half full of liquid. If the toilet bowl is empty, add water until it is half full.
  3. With the plunger, cover the flush hole but ensure there is still some water on the outside of it. Straighten the plunger to ensure the blockage is sealed properly.
  4. As with the plunging technique described above, push down until the plunger touches the drain then pull up quickly, taking care not to break the seal.
  5. Plunge a few times, then pull up sharply and break the seal in one motion. The blockage should dislodge when you release the suction.
  6. Repeat if necessary. If the blockage remains, you should call a plumber.

If the toilet blockage is persisting and there is more than one drain/toilet showing similar symptoms, or you’re not sure if you’ve made the problem worse, it’s time to call in a professional plumber.

Originally published as How to unclog a drain with a plunger by Darren Clancy. Author at .