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Why is my sink not draining?

A kitchen or bathroom sink not draining is one of those little problems in your home that you might notice and not deal with until it gets so bad you can’t use your sink. Make today the day you fix the problem with our guide to causes and solutions for why your sink isn’t draining….

A kitchen or bathroom sink not draining is one of those little problems in your home that you might notice and not deal with until it gets so bad you can’t use your sink. Make today the day you fix the problem with our guide to causes and solutions for why your sink isn’t draining.

We’ll look at the common reasons for water not draining from sinks, as well as ways to fix the problem and have a well-draining sink back again.

4 common reasons for water not draining from sinks

When plumbers are called out to fix a sink not draining, here are some of the most common causes they find that stop water not going down sink plugholes:

1. Food waste blockages

The number one culprit for a kitchen sink not draining is food waste. You may not realise it, but every day small bits of food (and some bigger bits too) end up down your kitchen sink when you’re cleaning dishes. Over time this can become a problem, especially if food like rice, pasta, butter and fats go down the plughole. This can easily create a blockage that leads to water not draining from sinks.

2. Build-up of soap

Sink that's been unblockedSimilar to butter and fats, soap can also build up in the pipes over time and narrow the space that water passes through. Left for too long and the soap clogging will lead to your sink not draining properly, or at all.

3. Foreign objects

It’s not just food and soap that can cause blockages that end up with water not going down sink plugholes. Other household items can also end up down the pipes and restrict or stop the water draining from the sin. Some of the common items found down a sink pipe include cotton wool, kitchen towel, small plastic toys, broken glass, and food wrappers.

4. Matted hair

Hair is one of the most well-known causes of drain blockages and is a particularly infamous cause for a bathroom sink not draining. Over time, hair can quickly build up from washing hair, shaving or clipping and get matted and tangled, which then causes a blockage that ends up with water not draining from the bathroom sink.

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Why is my bathroom sink not draining?

Whether you find that your bathroom sink drains slowly not getting air, or it looks like you have a slow draining sink not clogged by anything, you’ll want to find the problem and fix it.

Bathroom tap running in a sink not drainingHere are some of the top reasons why your bathroom sink keeps filling with water and not draining properly:

  • Matted and tangled hair in the plughole or pipes
  • Build up of soap scum
  • Small object(s) stuck in the pipes
  • Poor installation of plumbing and/or piping
  • Blocked drains (often caused by storms or heavy rainfall and you’ll most likely see the sink not draining but pipes clear of any obvious blockages)

Why is my kitchen sink not draining?

A blocked or poorly draining kitchen sink can be a real nuisance, so if you find your kitchen sink drains slowly not getting air to help it drain then it’s time to fix it. Here are the top reasons for your kitchen sink not draining:

  • Food waste blockages
  • Food wrapping and other plastics stuck in the pipes
  • Build up of butter, fats or soap scum
  • Damaged pipes

7 ways to unblock a sink that’s not draining

The best way to unblock a sink not draining properly will depend on the cause of the problem, as the various unblocking methods work in different ways. Here are seven ways you can use to unblock your sink:

1. Use the waste disposal (if you have one)

This might seem obvious, but if you have a waste disposal unit built into your sink then it should be your first step in trying to clear your sink. A build-up at the bottom of a disposal unit can sometimes cause a small blockage in the system if you haven’t used it in a while. Run the waste disposal and check it works properly, if the sink is still not draining then you’ll need to try another method.

2. Pour boiling water down the sink

A quick and easy solution that will clear some sinks, particularly those caused by a build-up of fats, is to pour boiling water slowly down the drain. Let it sit for 1-2 minutes to allow the boiling water to melt the fats and then run the hot top to clear the pipes.

3. Baking soda and vinegar solution

You can create a homemade unblocking solution using baking soda and vinegar, or baking soda and salt. Before pouring the solution down the sink, make sure you’ve cleared any standing water from the sink so that the solution can get to work on the blockage in the pipes.

First pour a cup of baking soda down the drain, followed by a cup of vinegar and then put the rubber plug stopper in. The solution should then fizz and push the clog down the drain, hopefully clearing it. After a few minutes pour hot water down the drain to clear out the solution.

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4. Baking soda and salt mixture

Another homemade remedy to cure water not going down a sink is to mix together a cup of baking soda with a cup of salt and pour it down the drain. Leave it for a few hours to break down any blockages clogging the pipes and then rinse with hot water to flush out any debris.

5. Use a plunger

Unblocking product being poured into sinkPlungers can often be a very effective way of clearing a bathroom or kitchen sink that’s not draining – especially if you have a lot of standing water in the sink that you can’t get rid of. Cover the whole drain hole with the plunger and plunge several times until you notice the water suddenly recede and drain away. That’s the theory anyway.

6. Insert a pipe snake

Persistent blockages that keep causing your sink not to drain might need to be physically unblocked using a pipe snake. A pipe snake is a thin, flexible cable that you can insert down the drain and it will bend with the shape of the pipe and break up any stubborn blockages. Once inserted into the drain, it’s helpful to move the pipe snake up and down to help properly break up any clogs – then flush the drain with hot water.

7. Sink unblocking products

Last, but not least, you can try a sink unblocking product from your local supermarket or hardware store. They can be pretty effective at unblocking sinks. Follow the manufacturer’s instructions on the label and always finish by flushing the drain with hot water afterwards.

How much does it cost to unblock a sink not draining?

The average cost of hiring a plumber to come and fix your blocked sink is around £50 per hour, depending on the complexity of the job and the individual plumber.

If your blocked sink is part of a bigger problem in your kitchen, you might need to install a new kitchen sink and taps – which could cost, on average, around £570 for materials and installation. To find out more, check out our guide on the cost to install a kitchen sink and taps.

If you are at all unsure on the cause of your blockage, then we would highly recommend getting a plumber in to avoid any further damage

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