How to Unblock a Bathroom Sink

How to Unblock a Bathroom Sink

There are few things more frustrating in a bathroom than water not draining from your sink or water rising when it shouldn’t.

There’s no reason why you should let a blocked sink ruin your day. But before you quickly Google local plumbers, you should know that you can sort the problem yourself. But how do you unblock a bathroom sink? It’s actually easier than you think.

Plumbworld is here to explain the various methods you can use to unblock a bathroom basin without using potentially harmful chemical-based cleaners. We’ll also discuss what can block your bathroom sink so you’re aware in the future. The last thing you want is your basin to overflow all over your bathroom floor, bath mat, or even your bath or bathroom furniture.

Read on to find out how to unblock a bathroom sink quickly and easily…

Why is my bathroom sink blocked?

why is my bathroom sink blocked?

When it comes to a blocked bathroom basin, there are three common causes with only one of these being in your control. They are:

  • Foreign objects
  • Poor installation
  • Storms and bad weather

We’ve explained each one in more detail below.

Foreign Objects

The most common cause of a blocked sink is also the one you have control over - something getting stuck in the system. By foreign objects, we mean materials such as hair, soap and toothpaste, as well as general grime and dirt. These all end up going down the plughole.

Sometimes, this dirt and material can build up further down the pipes and cause a blockage which is only noticed when slow-draining water becomes more of a pool that takes time to clear.

In most cases, this doesn’t require a plumber as sections of piping underneath a sink can be removed and cleaned. If an object is larger that’s been accidentally dropped down the plug, it will likely have been caught in the basin trap. This is specifically designed for this job and should be easy to access.

Poor Installation

Arles Cloakroom Suite

If you constantly have a blocked sink, it may be down to poorly installed plumbing and piping. Water flow is dependent on gravity, so pipes that have been fitted with wrong falls or angles can easily lead to a build-up of material that causes blockages.

This cause is most likely out of your control unless you decided to fit the piping yourself. DIY repairs can be the cause, an unknowledgeable but eager DIYer hasn’t quite understood the basics. So, it’s always worth speaking to a professional plumber.

If you have constant gurgling sounds, water draining slowly or bad smells, then you might have a larger problem that may only be fixed by a professional.

Storms & Bad Weather

Yes, the weather really can be a cause of blocked sinks. Heavy rain during a storm can cause drains to become blocked outside, which will then back-up into your home.

Read more: How to Unblock a Toilet

This happens because leaves, dirt and debris can be washed into drains by a downpour. However, even just a large volume of water can cause a problem. Unless the drain is your main outside-access, there isn’t much you can do and it often solves itself.

How can I unblock a bathroom sink?

how can I unblock a bathroom sink?

Now, we’ll run you through a few different options for unblocking a bathroom basin using natural products from around your home.

For these, you may need:

  • A plunger
  • Rubber gloves
  • Bucket
  • Towel
  • Baking soda
  • Vinegar
  • Adjustable spanner
  • Boiling water

Use a Plunger

If the blockage is in the upper part of the waste pipe - you may be able to see it - you should be able to move it with a bathroom plunger. You’ll need:

  • A plunger
  • Rubber gloves


  1. First, remove the pop-up plug or the drain stopper. Then, block the overflow with a cloth or tea towel to create a vacuum. 
  2. Then, place the plunger’s suction cup part over the plughole and make sure you completely cover the entire plughole. Ensure you have water in the basin to cover at least half of the plunger head.
  3. Then, push down gently so it creates a seal before pumping repeatedly in a vertical motion at a steady pace for a few minutes. Release the plunger to let the air out and repeat this until the water drains. 
  4. The suction created should move whatever is causing the blockage. You can then reach down and remove the blockage.
  5. If this doesn’t work and the water is still sitting in the sink, try a different method.
Marseille Cloakroom Suite

Use Baking Soda & Vinegar

This option is worth trying if your sink isn’t completely blocked, but it is draining slower than it should be. It will dissolve a blockage using products you can find in a kitchen. You’ll need:

  • Bicarbonate of soda (baking soda)
  • White vinegar
  • Boiling water
  • Rubber gloves


  1. First, make sure the water has drained away and your basin is empty and dry.
  2. Then, pour one cup of baking soda down the drain, followed by two cups of boiling water. You’ll then have to wait about 3 - 5 minutes.
  3. Once this is done, pour another cup of baking soda, followed by one cup of white vinegar, down the drain.
  4. Let the fizz and bubbles come out. Once they’ve disappeared, pour two cups of hot water down the drain.
  5. After about twenty or thirty minutes, check to see if the problem has been resolved.

Remove the Waste Trap or U-Bend

If using natural products or a plunger doesn’t work, it’s time to get underneath the sink to remove the U-bend, technically called a waste trap. For this, you’ll need:

  • Rubber gloves
  • Bucket
  • Adjustable spanner/wrench
  • Screwdriver
  • Old towel or rag


  1. First, make sure the water is turned off and you’ve cleared the space underneath your sink.
  2. Then, place a towel and bucket underneath the basin to catch any water that may come out once you’ve taken the U-bend off.
  3. Note down how the U-bend is constructed so that you’ll be able to put it back together properly later on.
  4. Carefully loosen the fittings that connect the U-bend to the basin with a wrench or screwdriver. Make sure you’re ready for any water that comes out.
  5. Be careful not to lose any additional fittings, such as rubber seals or washers, that might be in place in the U-bend.
  6. Remove the U-bend and clear the blockage by pushing a piece of flexible wire through the pipe or even using your hands if you can see and grab it.
  7. Once you have cleared the blockage, reassemble the U-bend in the same way you took it apart and replace it, making sure it’s completely sealed at both ends.
  8. Turn the water back on.

If you're looking for further DIY advice, you may find the following posts useful - How to Unblock a Toilet - How to Replace a Toilet Seat - DIY Home Improvements.

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