How to Unblock a Sink

The most common plumbing problem homeowners come up against is the blocked sink.

Signs of a clogged sink include foul smells from your plughole, slow drainage, water in the sink when there is no plug in the plughole and gurgling noises during draining. A blocked sink can be caused by the build-up of oils, greases, fats or soap residue in the drain, foodstuffs stuck in the U-bend or even pieces of plastic, paper or cotton buds that have found their way down the plughole. Unless the problem persists, there’s no need to call a plumber as we’ve put together a step-by-step guide to help you unblock your sink yourself.

Unblocking a Sink: Safety Precautions

Before you start we recommend you wear eye protection goggles and rubber gloves for all methods of unclogging your sink, and even a mask to protect from fumes and smells. For methods one, four and five we also recommend you place newspaper or towels on the floor to protect it from any potential spills or splashback.

Method One: The Plunger

The first step when unblocking any sink should be to try a traditional plunger method. A plunger will add and remove air through the pipe to forcefully dislodge any blockage.

What you will need:

  • A dishcloth or small towel
  • A plunger


  1. Start by removing the plug and then cleaning the plughole as best you can, trying to get rid of any debris, grease or grime that has built up around it.
  2. Cover the plughole with water, creating an airtight seal for when you’re plunging.
  3. Using a dishcloth or small towel, cover and tightly seal the sink overflow to once again ensure there’s an airtight seal for the plunger - you may need to hold the dishcloth to achieve this.
  4. Once you are sure the plughole is tightly sealed, place the plunger over the plughole so that it’s completely covered, begin to plunge up and down.
  5. See if the water drains easily to test whether or not the sink has been cleared.

Method Two: The Blast Method

A second attempt to unclog the sink without using any chemical reactions, chemicals or getting surgical, this method uses the force of water going down the drain to flush or dislodge any debris or build-ups.

What you will need:

  • A milk carton or 2ltr drink bottle
  • Hot water


  1. Fill milk carton or bottle with hot water.
  2. Tip bottle upside down, ensuring the lid is directly over the plughole.
  3. Squeeze the bottle, forcing water out as quickly as possible to blast any potential blockage in the drain.
  4. Test whether water drains easily and the sink has been unblocked.

The next two methods use chemical reactions to remove soap residue, oil, fat and grease from drain.

Method Three: Baking Soda and White Vinegar

For this method we recommend you wear a mask to protect yourself from any fumes.

What you will need:

  • Baking Soda
  • White vinegar
  • Hot water


  1. Pour a small amount (around half a cup) of baking soda down the plughole.
  2. Pour some white vinegar (around a cup) down the drain.
  3. You should hear fizzing and potentially see some foam as the vinegar and the baking soda react. As they reaction happens, it will remove soap residue, oil, fat and grease clinging to the pipes.
  4. Leave this to work for a few minutes.
  5. Flush through with hot water.
  6. Test to see if water drains easily and if the blockage has gone.

CAUTION: Do not follow with bleach as vinegar and bleach react to create toxic chlorine gas.

Method Four: Soda Crystals

This is a simple method using dissolvable soda crystals. Be careful not to scald yourself with the boiling water.

What you will need:

  • A jug
  • Half a packet of soda crystals
  • Boiling water


  1. In an easy pouring jug, dissolve half a packet of soda crystals in boiling water.
  2. Pour solution down the plughole. This will remove fats, oils, soap residues or greases that have built up in the drain
  3. Leave for a while.
  4. Check if the water drains easily from the sink to test if the blockage has cleared.

Method Five: Removing the U-bend

For this method, you’ll have to position yourself under the sink and get your hands dirty. Be sure to put down a towel or some old newspaper to avoid any water damage or staining from potential leaks or spillages.

What you will need:

  • A wash basin or bowl
  • Waterproof tape
  • Dishcloth
  • Warm water
  • A wire hanger or screwdriver


  1. 1. First off, find the U-bend. The U-bend if the first bend in the pipe from the plughole, underneath the sink.
  2. 2. Place the wash basin under the pipe to collect any water or waste spillage.
  3. 3. Slowly unscrew the thread closest to you on the U-bend. This should cause water to begin to drain out of the pipe. Allow this to drip into the basin until it stops.
  4. 4. Unscrew the back thread of the U-bend, and once again wait for any leaking water to subside.
  5. 5. Carefully remove the U-bend, being conscious of anything that may come out of it.
  6. 6. Check inside the U-bend pipe for any debris or blockages and clean it out thoroughly. You can do this using the wire hanger, or screwdriver, and a dishcloth with some warm water.
  7. 7. Once you are sure the pipe is clean, screw the U-bend back in place. Then seal the pipe with waterproof tape to ensure that there are no leaks and that the pipe is watertight.
  8. 8. Run the water to see if the sink drains quickly, without issue, to tell if the blockage has cleared.

If none of these methods work for you, it may suggest there is a problem deeper within the drainage system. This is when it’s time to call a plumber.

Avoiding a Blocked Sink

Avoiding a blocked sink is simple and saves the hassle of clearing the obstruction yourself or having to call out a plumber. Some of our tips for preventing a blocked sink include:

  1. Keep an eye on what is going down your sink. For example, avoid draining roasting tins full of fat down the kitchen sink.
  2. Educate your children on what they can and can’t put down the plughole. Avoid cotton buds, toys or bits of plastic.
  3. Try not to put oils, foodstuffs, paper products, greases or fats near the sink or down the plughole.

Prevention is always the most effective tool but on the off-chance that your sink clogs up, we hope this guide will have helped you to unblock your sink and avoid any unnecessary plumbing bills.