Drain Unblocking Service London: Costs and What to Check First
A blocked sink, slow-draining bath or gurgling toilet usually isn't an emergency, but it rarely gets better on its own. A reliable drain unblocking service in London should attend within hours for internal blockages, clear the obstruction with rods or a hand pump, and tell you plainly if the problem is actually on the shared sewer, where the water company takes over. Typical cost for a standard internal unblock runs from around £80 to £180. External or main drain work costs more, from £120 to £350 depending on access and whether jetting equipment is needed. Get a fixed price before anyone starts.
Contents
- What a drain unblocking job actually covers
- Drain unblocking service London cost
- Signs your drain is blocked, not just slow
- Who's responsible: you, your landlord, or Thames Water
- What happens on a callout
- The one mistake that makes it worse
- Rodding, jetting or a CCTV survey: which do you need
- Areas we cover
- FAQ
What a drain unblocking job actually covers
Most calls we get in London fall into one of two groups. The first is an internal blockage: a kitchen sink that won't drain, a bath that empties slowly, a toilet that won't flush properly. These are nearly always caused by fat, hair, soap build-up or something that shouldn't have gone down in the first place, and a handyman or drainage technician can usually clear them in under an hour with rods, a plunger pump or an auger.
The second group is external: a gully outside the kitchen window, a manhole in the garden, or the main run between the house and the street. These jobs need different kit, often a van-mounted jetter, and they take longer to diagnose because you can't see the blockage. If you're not sure which you've got, the honest answer is that any competent tradesperson should be able to tell within a few minutes of looking, usually for free or for a modest call-out fee that gets deducted from the job if you go ahead.
Drain unblocking service London cost
Prices below are typical ranges across London for 2026. Actual cost depends on access, how severe the blockage is, and whether it's a daytime or out-of-hours call. Always ask for a fixed quote once the engineer has looked at the job, not just a phone estimate.
| Job type | Typical cost | Usual time on site |
|---|---|---|
| Internal blockage (sink, bath, toilet) | £80 to £150 | 30 to 60 minutes |
| External gully or yard drain | £100 to £180 | 45 to 90 minutes |
| Manhole or main drain rodding | £120 to £220 | 1 to 2 hours |
| High pressure jetting (grease, roots) | £180 to £350 | 1 to 3 hours |
| CCTV drain survey with report | £150 to £300 | 1 to 2 hours |
| Out of hours or weekend callout | Add roughly £40 to £80 | Depends on access |
Properties in Chelsea, Kensington and Belgravia with period plumbing and older cast iron or clay pipework sometimes cost a little more, simply because the runs are longer or harder to access under original floors. In newer conversions around Battersea, Clapham or Canary Wharf the pipework is usually more straightforward and jobs tend to sit at the lower end of these ranges.
Signs your drain is blocked, not just slow
A slow drain and a blocked one aren't the same problem and the fix is different. Watch for these:
- Gurgling noises from a sink or toilet when another fixture drains, which usually means air is trapped behind a partial blockage further down the stack.
- Water rising in a second fixture when you flush or drain another one, for example the bath filling slightly when the washing machine empties.
- A bad smell near a gully or manhole outside, often the first sign of a blockage on the external run rather than inside the house.
- Standing water in the manhole if you lift the cover. Clear water running freely means the problem is upstream of that point, not downstream.
If it's just slow and nothing else is affected, a kettle of hot water (not boiling, which can crack some pipe joints) and a bit of patience sometimes clears it. If more than one fixture is involved, that's a genuine blockage and worth booking someone properly rather than waiting.
Who's responsible: you, your landlord, or Thames Water
This is the question that trips up most homeowners and tenants, and it genuinely does change who pays. In general terms, the pipework inside your property boundary, including the branch that runs from the house to the point where it joins a shared or public sewer, is your responsibility (or your landlord's, if you rent). Once the blockage is on the shared section of sewer, which for most London terraces and conversions sits somewhere under the front garden or pavement, that's typically the water company's responsibility to clear, usually at no cost to you.
Since private sewers were transferred to water company ownership in England back in 2011, this split confuses a lot of people, because the pipe physically still runs under your own garden. The practical rule we use on site: if the blockage is between your property and the first manhole or inspection chamber nearest the house, it's generally your job. Beyond that, it's worth a call to your water supplier before paying for private work that might not have been needed. A good engineer will tell you honestly if they think it's a Thames Water matter rather than just taking the job anyway.
What happens on a callout
A standard visit for a blocked drain in London looks roughly like this:
- The engineer asks what's blocked, when it started, and whether more than one fixture is affected, which narrows down internal versus external before they even arrive.
- On site, they check the nearest inspection chamber or manhole first. If it's running clear, the problem is inside the house.
- Internal blockages get cleared with a hand auger, plunger pump or rods fed through the access point nearest the obstruction.
- External blockages usually need rods fed from the manhole, or a jetter if it's grease, roots or a long run.
- Once clear, they run water through for several minutes to confirm it's flowing properly, not just partially cleared.
- You should get a plain explanation of what caused it and whether it's likely to recur, not just an invoice.
For anything beyond a simple clear, especially recurring blockages or suspected pipe damage, it's worth asking for a CCTV survey before paying for repeated callouts on the same drain.
The most expensive mistake: pouring chemical drain cleaner down first. Caustic drain cleaners can make a blockage worse by turning fat and hair into a solid plug, and they create a genuine safety hazard for whoever has to clear it afterwards, since the chemical can splash back during rodding. We've attended jobs in Fulham and Putney where a £15 bottle of drain cleaner turned a 30 minute job into a two hour one with extra labour charged for safe disposal of the chemical residue. If a drain is properly blocked, book an engineer rather than reaching for the cleaning cupboard.
Rodding, jetting or a CCTV survey: which do you need
These three get used interchangeably by customers and they're not the same thing.
| Method | Best for | Not suitable for |
|---|---|---|
| Manual rodding | Straightforward blockages, hair, soft debris, single-point obstructions | Long runs, grease build-up, tree root ingress |
| High pressure jetting | Grease, scale, tree roots, recurring blockages on the same run | Fragile or already-cracked old pipework, which jetting can damage further |
| CCTV survey | Diagnosing recurring blockages, pre-purchase checks, suspected collapsed pipe | A one-off simple blockage that's never happened before |
If a drain has blocked three or four times in a year, rodding alone is a sticking plaster. Ask for a CCTV survey so you actually know whether it's roots, a sagging section of pipe, or a genuine collapse that needs digging up and replacing. That's a different job and a different price entirely, and it's better to know before you commit.
Drain problems often show up alongside other maintenance issues that get missed until something backs up, particularly in older houses across Hampstead, Highgate and Richmond where original pipework is still in place. If you're dealing with a wider list of niggling jobs rather than one isolated blockage, our property maintenance service in London covers exactly that kind of ongoing check-up. And if a blockage happens outside normal hours and water is actively coming up through a floor or overflowing a gully, our emergency handyman service in London is the faster route than waiting for a daytime slot.
Worth noting too: a surprising number of "blocked drain" calls in autumn and winter actually trace back to blocked gutters overflowing into a gully rather than the drain itself being obstructed. If leaves and debris are the real culprit, our guttering services in London page covers clearing and maintaining gutters before they cause a drainage problem that isn't really a drainage problem at all.
Areas we cover
We handle drain unblocking jobs across central and south west London and into the wider boroughs, including Chelsea, Kensington, Knightsbridge, Belgravia, Mayfair, South Kensington, Marylebone and St John's Wood. Further out, we cover Wimbledon, Putney, Barnes, Richmond and Kew, plus Fulham, Battersea, Clapham, Notting Hill, Holland Park, Islington, Primrose Hill, Highgate, Hampstead and Dulwich. If you're outside these areas, give us a call anyway, as we often cover adjacent postcodes depending on the day.
FAQ
How much does a drain unblocking service cost in London?
A standard internal blockage, such as a sink or toilet, typically costs between £80 and £150. External gullies and manhole or main drain rodding run from £100 to £220. High pressure jetting for grease or tree roots costs £180 to £350. Out-of-hours callouts usually add £40 to £80 on top. Get a fixed quote once the engineer has assessed the job on site, since phone estimates can shift once the blockage is actually visible.
Who is responsible for a blocked drain, me or Thames Water?
Pipework inside your property boundary is generally your responsibility, or your landlord's if you rent. Once the blockage sits on the shared sewer, usually beyond the first manhole nearest the house, it typically becomes the water company's responsibility to clear free of charge. Since private sewers transferred to water company ownership in England in 2011, this can surprise homeowners who assume anything under their own garden is their problem. Check the nearest manhole before paying for private work.
How do I know if my drain is blocked or just slow?
A slow drain affects one fixture and usually clears with hot water and patience. A genuine blockage affects multiple fixtures at once, causes gurgling noises, or makes water rise in a second sink or bath when another one drains. A bad smell near an external gully or standing water in a lifted manhole cover are also signs of a real blockage rather than a simple slow run.
Can a handyman unblock a drain or do I need a specialist drainage company?
A competent handyman can clear most internal blockages, sinks, baths, toilets and gullies, using rods, a pump or an auger. For jobs needing high pressure jetting equipment, CCTV surveys, or main sewer work beyond the property boundary, you need a specialist drainage contractor with that kit. A good handyman will tell you honestly which category your job falls into rather than attempting something outside their equipment range.
What is drain jetting and do I need it?
Drain jetting uses a high pressure water hose fed through the pipe to blast away grease, scale and tree root ingress that rodding can't fully clear. You typically need it if a drain has blocked repeatedly on the same run, or if rodding has only given a temporary fix. It's not usually necessary for a one-off simple blockage, and it can damage already cracked or fragile old pipework, so ask first if that's a concern.
Is drain unblocking covered by home insurance?
It depends on the policy and the cause. Many home insurance policies cover drain unblocking if the blockage results from an insured event, such as storm damage or accidental damage to pipework, but routine blockages from fat, hair or debris are usually treated as maintenance and excluded. Some insurers offer separate drainage cover as an add-on. Check your specific policy wording or call your insurer before assuming a claim will be accepted.
How quickly can someone come out for a blocked drain in London?
For non-emergency internal blockages, same-day or next-day appointments are standard across most of London, including Wimbledon, Chelsea and Kensington. If water is actively backing up, overflowing, or coming through a ceiling or floor, that counts as an emergency and a tradesperson should be able to attend within one to three hours depending on your exact location and time of day.
What should I avoid doing before the drain engineer arrives?
Don't pour chemical drain cleaner down the blockage. It can solidify fat and hair into a harder plug and creates a safety hazard for whoever clears it. Avoid running more water down the affected fixture, which can cause an overflow if the blockage is severe. If it's an external gully, don't lift the manhole cover unless you're checking whether the problem is upstream or downstream, and replace it carefully afterwards.