How much does it cost to unblock a sink?

Unblocking a sink typically costs £60 to £150, depending on how stubborn the blockage is and what's causing it. Simple blockages near the plughole are quicker and cheaper to clear. Deeper blockages or those caused by grease build-up may take longer. We quote fixed prices before we start, so you know exactly what you're paying.

What causes a kitchen sink to block?

The main causes are grease, fat, and food debris. Cooking oils and fats solidify as they cool in the pipes, sticking to the walls and trapping food particles. Over time, this narrows the pipe until water struggles to get through. Coffee grounds, rice, pasta, and vegetable peelings make things worse because they swell with water and clump together.

What causes a bathroom sink to block?

Hair is the biggest culprit - it goes down easily but tangles in the drain and trap, combining with soap scum and toothpaste to form dense clogs. Soap contains fats that create a sticky residue called soap scum, which coats the inside of pipes. Toothpaste can also harden in the pipes if it's not rinsed through properly.

How long does it take to unblock a sink?

Most blocked sinks take 30 minutes to an hour to clear. Simple blockages near the plughole can be done in minutes. Deeper or more stubborn blockages may take longer, especially if we need to remove and clean the trap or use specialist equipment. If the problem is further down in the waste pipe, it may require more time.

Can I unblock a sink myself?

You can try. A plunger often works for minor blockages, and pouring boiling water down the drain can help dissolve grease. Baking soda and vinegar is a popular DIY method that works on small clogs. But if you've tried these and the sink is still blocked - or if it keeps blocking - there's probably a more stubborn build-up that needs professional clearing.

Is it bad to use chemical drain cleaners?

We don't recommend them for regular use. Chemical cleaners can damage older pipes, especially clay or cast iron systems. They often only partially clear blockages, leaving residue that quickly builds up again. They're also harsh on the environment and can cause burns if they splash. Professional clearing is more thorough and safer for your pipes.

Why does my sink keep blocking?

Recurring blockages usually mean there's a build-up deeper in the pipe that isn't being fully cleared. Each time you unblock it, you're only shifting part of the problem. The underlying cause - grease coating the pipe walls, hair trapped in the trap, or debris caught further down - stays in place and blocks again. A proper clean removes everything.

Should I pour boiling water down a blocked sink?

It can help with grease blockages in kitchen sinks - the hot water melts fat deposits and washes them away. But be careful with older pipes or plastic fittings, as very hot water can damage them. For bathroom sinks, boiling water is less effective because the blockage is usually hair and soap, which don't dissolve with heat.

What's the U-bend and why does it block?

The U-bend (also called a P-trap) is the curved pipe under your sink. It holds a small amount of water that stops sewer gases coming back up into your home. But its shape also makes it a trap for debris - hair, soap, food, and grease collect in the bend and cause blockages. Cleaning the U-bend often fixes a blocked sink completely.

Can a blocked sink cause other problems?

Yes. Standing water in a blocked sink creates bad smells as debris decomposes. Long-term, water backing up can damage your sink and surrounding surfaces. If the blockage is in a shared waste pipe, it can affect other fixtures too - you might notice your bath or toilet draining slowly. Persistent blockages should be investigated properly.

How can I prevent my sink from blocking?

In the kitchen, never pour cooking oil or fat down the drain - collect it in a container and put it in the bin. Scrape plates into the bin before washing up. Use a sink strainer to catch food debris. In the bathroom, use a drain cover to catch hair, and rinse the sink properly after brushing teeth. A weekly flush with hot water helps too.

Blocked sinks

Get your kitchen or bathroom sink draining freely again - fast.

Kitchen sinks blocked by grease, fat, and food debris

Bathroom sinks clogged with hair, soap, and toothpaste

Fixed pricing with no callout fees

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Why choose OneFlow?

based on 180+ Google reviews

No callout fees

You only pay for the work itself. No charges for coming out, no minimum fees - just a fair price for getting your sink working again.

Fixed pricing

We quote a fixed price before we start. Whether it's a simple blockage or something more stubborn, you know exactly what you're paying.

We fix it properly

We don't just clear the blockage and leave. We make sure your sink is draining freely, check nothing else is causing the problem, and give you honest advice on preventing it happening again.

Same-day service

A blocked sink disrupts your whole day. That's why we offer same-day callouts across our coverage area - so you're not waiting around with a sink full of standing water.

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Most blocked sinks cleared in under an hour

Back to normal quickly - with advice on how to stop it happening again.

98%

Of customers would recommend us.

3000+

Jobs completed last year alone.

Kitchen or bathroom - we clear both

Whether it's a kitchen sink that won't drain after washing up or a bathroom basin backing up every time you brush your teeth, we'll get it flowing freely again.

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Kitchen sinks

The usual culprits are grease, fat, and food debris. We clear the blockage and remove the build-up so it doesn't come straight back.

Bathroom sinks

Hair is the biggest problem here. We remove the blockage completely and clean out the trap so your sink drains properly again.

Why choose a local team?

See how we compare to the big brands.

The big names

What you often get with the big names.

Minimum callout charges even for small jobs

Hourly rates that add up while they work

Quick fix that clears the blockage but leaves the build-up

Upselling you services you don't need

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OneFlow

What you get when you call us.

No callout fees - you only pay for the work

Fixed pricing quoted before we start

Thorough clearing that removes the cause, not just the symptom

Honest advice on prevention, not unnecessary extras

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What our customers say

Real reviews from real customers.

“Called at 6am with sewage coming up through the shower. Engineer arrived before 8, fixed it within the hour. Can't thank them enough.”

— James T, Southampton

“Third company I'd tried that week. The other two never showed. OneFlow answered, turned up same day, and actually fixed it. Should have called them first.”

— Michelle R, Brighton

“No messing about. Showed me the camera footage, explained what was wrong, gave me a price, and got on with it. Exactly how it should be.”

— David H, Portsmouth

“Blocked drain on Christmas Eve. Thought we'd be stuck for days. They came out that evening and sorted it. Absolute lifesavers.”
‍

— Sarah K, Guildford

“We've used them for three rental properties now. Always answer the phone, always turn up, always fair on price. Hard to find.”
‍

— Mark L, Bournemouth

“Engineer was honest and said we didn't need half the work another company had quoted for. Saved us hundreds. We'll use them every time now.”

— Karen W, Winchester

“Toilet blocked on the morning of our daughter's birthday party. They had someone here within the hour and sorted it before the guests arrived.”

— Rachel M, Crawley

“Other companies quoted over the phone then doubled it on arrival. OneFlow quoted £180, charged £180.”
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— Tom S, Bournemouth

“Drainage issue had been misdiagnosed twice by other firms. OneFlow found the real problem in ten minutes with their camera. Fixed the same day.”

— Angela D, Eastbourne

“Rang at 11pm expecting to leave a voicemail. Actual person answered. Engineer here by midnight. Didn't think companies like this still existed.”

— Chris B, Woking

FAQs

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Got a blocked sink?

Same-day callouts. Fixed pricing. No callout fees.

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90-minute average response across the UK.

★★★★★ based on 180+ Google reviews