A plumber once told me he’d pulled eighteen months of congealed bacon fat out of a single kitchen trap in Croydon. It looked like a candle. That job cost the homeowner £95 because she’d left it so long the grease had set solid against the pipe wall. Had she called someone three weeks earlier, it would have been a £45 job with a plunger and ten minutes.
That’s the whole story with sink blockages, really. The cost to unblock a sink in the UK depends almost entirely on how long you waited and what’s actually causing the clog. Kitchen sinks and bathroom basins fail for completely different reasons, and that changes the price more than most cost guides admit.
Contents
- What Affects the Price You’re Quoted
- Average Cost to Unblock a Sink in 2026
- Cost Table: Kitchen Sink vs Bathroom Basin
- Try This Before You Call: DIY vs Professional
- How to Get a Fair Quote and Avoid Being Overcharged
What Affects the Price You’re Quoted
Every drainage engineer prices a blocked sink the same rough way: how bad is it, how far down the pipe is it, and what tools does it need. That’s it. Everything else is detail.
A blockage sitting in the U-bend under the sink is a five-minute fix. A blockage 3 metres down the branch pipe, past the trap and into the wall, needs rods or an electric eel and a lot more patience. Grease-based blockages in kitchens often need hot water jetting or a chemical breakdown, while bathroom basin blockages are usually a physical mass of hair and soap scum you can hook out by hand.
Access matters too. A sink with an accessible trap under a cupboard is quick. A sink boxed in behind a vanity unit, or plumbed into a wall with no isolation valve, adds 20-30 minutes of dismantling before the engineer even sees the blockage.
Then there’s timing. A callout on a Tuesday morning is cheaper than a Sunday night emergency, full stop. According to Checkatrade, out-of-hours drainage callouts in the UK routinely carry a 25-50% premium, and that lines up with what we see on jobs across London and the Home Counties.
Average Cost to Unblock a Sink in 2026
Across the UK, the average cost to unblock a sink sits between £60 and £150 for a standard callout. That’s for a straightforward job: engineer arrives, clears the trap or the first metre of pipe, tests the flow, leaves.
Push into a more stubborn blockage — one needing rods, an electric eel, or a jetting unit — and you’re looking at £120 to £250. If the blockage has caused a leak, damaged the trap, or sits somewhere that needs partial pipework removal, costs climb past £300.
Price range in plain terms: £45 at the cheap end for a quick plunge-and-clear, up to £350 for a genuinely stubborn or hard-to-reach sink waste blockage cost involving specialist kit. Most jobs land in the £80-£130 bracket. MyJobQuote quotes a similar national range, which tells you the market has settled rather than being wildly inconsistent between tradespeople.
London and the South East run 15-25% above that national average. A £90 job in Nottingham is closer to £115 in Wandsworth. Not because the work is different — because overheads, van costs and demand are higher.
Kitchen vs Bathroom: The Blocked Sink Cost Table
This is the bit most guides skip, and it’s the bit that actually matters. A kitchen sink blockage and a bathroom basin blockage are not the same job, and pricing them identically is lazy.
Kitchen sinks block with grease, food starch, coffee grounds and fat that cools and hardens inside the pipe. It builds in layers, narrowing the pipe gradually until one day it just stops. Clearing it often needs hot water, degreasing agents or jetting, because a plunger alone just pushes the fat further down.
Bathroom basins block with hair, soap scum and limescale, especially in hard water areas like Reading, Oxford or most of Essex. That’s a physical mass rather than a chemical coating, so it tends to respond well to a drain snake or a simple trap clean.
| Blockage Type | Typical Cause | Average Cost (2026) | Method Used |
|---|---|---|---|
| Kitchen sink — trap only | Fat, food debris | £45 – £85 | Manual trap clear |
| Kitchen sink — pipe run | Set grease, starch build-up | £110 – £220 | Jetting / hot flush |
| Bathroom basin — trap only | Hair, soap scum | £45 – £75 | Manual trap clear |
| Bathroom basin — pipe run | Hair mass, limescale narrowing | £90 – £160 | Drain snake / rodding |
| Either — emergency/out-of-hours | Any of the above | +25% – 50% | Same methods, priority callout |
| Either — CCTV diagnosis needed | Recurring or unknown blockage | £120 – £250 | CCTV drain survey |
If a blockage keeps coming back within weeks, that’s usually a sign the problem isn’t in the sink at all — it’s further down the shared drain. That’s when a CCTV drain survey earns its money, because guessing at that point just burns cash on repeat callouts.
Try This Before You Call: DIY vs Professional
Here’s the two-minute test I tell every customer to try before booking anyone. Boil a full kettle, pour it slowly into the sink in three stages, thirty seconds apart, and watch how it drains.
If it drains slower each time and eventually stalls, you’ve got a build-up in the trap — that’s a DIY job. Grab a plunger, block the overflow with a wet cloth first, and give it ten firm pushes. Kitchen sinks respond to a bicarbonate-of-soda-and-vinegar flush after that; bathroom basins usually just need the trap unscrewed and the hair pulled out by hand.
If the water doesn’t move at all, or it gurgles and backs up in a different fitting (the bath, the toilet), stop. That’s not a sink problem anymore — that’s further down the system, and DIY tools will not reach it.
DIY saves you the £45-£85 minimum callout, no argument there. But drain rods used badly can crack an old ceramic trap, and chemical drain cleaners left too long can damage plastic pipework — I’ve replaced traps that cost £70 to fix because a caustic cleaner sat in there for three days.
If you’ve tried the kettle test, the plunger, and a basic trap clean and it’s still blocked, that’s the point to stop and book a professional drain unblocking service rather than keep pouring chemicals down it.
How to Get a Fair Quote and Avoid Overpaying
Ask for a fixed price before anyone turns a key in the van, not an hourly rate with “it depends” attached. A fixed quote for a standard kitchen or bathroom sink blockage should be given over the phone once you’ve described the symptoms.
Get it in writing what’s included. Some companies quote £49 for the callout then add £60 for “access” or £40 for “waste disposal” once they’re on site. That’s not a fair quote, that’s a bait price.
Water UK notes that a huge proportion of household blockages are preventable — wipes, fat and sanitary products account for most sewer misuse complaints nationally. Worth remembering before you pour that pan of bacon fat down the plughole.
If your quote seems high, check it against the drain unblocking cost guide for the wider drainage market — a sink blockage should always price lower than a full drain unblock, because the run is shorter and access is easier.
For a straight answer on your specific job, it’s faster to speak to someone than to keep Googling variations of “unblock kitchen sink price.” Get in touch through our contact page and we’ll give you a fixed figure before anyone leaves the yard.
Why the Same Blockage Costs More If You Wait
This is the pattern I’ve seen for twenty years and it never changes. A blockage caught early costs a plunger and ten minutes. Left three months, it costs a callout. Left a year, it costs a callout plus jetting plus, sometimes, a section of pipe.
The Croydon job I mentioned earlier is the extreme version, but the shape of it repeats constantly. A slow-draining kitchen sink in Colliers Wood, ignored for two months, becomes a full jetting job by the time anyone calls. Customers in Colliers Wood and Crystal Palace tend to see this most in older Victorian terraces, where narrow original pipework has zero tolerance for grease.
Same story in Buckhurst Hill, Blackheath and Tunbridge Wells — hard water areas where limescale narrows bathroom waste pipes years before anyone notices the sink’s running slow.
The real cost-saving move isn’t finding the cheapest tradesperson. It’s not letting a slow sink sit for three months while you get used to it. A £45 job now beats a £250 job in the spring, every single time.
If your sink’s already past the kettle test and the plunger, don’t keep pouring chemicals down it and hoping. Ring our team through the contact page and get a fixed price sorted before it turns into the £300 version of this problem.
Understanding cost to unblock a sink early helps you budget and avoid bigger repair bills later.
