A blocked drain is annoying; a blocked drain that backs up into a basement flat in heavy rain is a different problem — and it might not even be yours to fix. Every drainage plumber listed here for Kensington & Chelsea is checked and verified before going live.

✅ Checked before listing — identity, insurance, trading presence, Gas Safe (where relevant). How we verify →
✅ Workmanship guarantee badges on listings — 1, 3, 6 or 12 months

⚠️ Sewage backing up? Treat it as a contamination hazard — keep children and pets away, don’t use the affected toilet or sink, and wash your hands thoroughly after any contact. If it’s backing up across the building or from a manhole in the road, the cause may be the public sewer rather than your own drain. Staying safe, and who’s responsible ↓

Contact verified drainage plumbers in Kensington & Chelsea ↓

Coverage: W8, W10, W11, W14, SW3, SW5, SW7, SW10, plus the SW1W/SW1X, W2 and NW10 edges that clip the borough.
What this covers: slow and blocked sinks, baths, toilets and outside drains — clearing the blockage, finding the cause with a drain camera, and sorting recurring or collapsed-drain problems.
Routing: clean water rather than waste → Leak Detection; a single slow-flushing loo → Toilet Repairs; a restaurant or food premises → Commercial Plumbing.
Costs: prices depend on the method needed and whose drain it is — see what affects the price.
Availability: each plumber sets their own hours and response times, shown on their listing.

Jump to: What’s blocking it · Whose drain is it · Safety first · By district · Costs · FAQs

What blocks a drain — and whether it’s yours to clear

Thames Water lists the usual signs of a blockage as a toilet that’s hard to flush, a sink or bath that empties slowly, a bad smell from the drains, and wastewater coming back up.¹ The culprits are usually predictable: Thames Water says sewers are designed only for the “three Ps” — pee, poo and paper — and that the big offenders are fat, oil and food scraps that solidify, wet wipes (even ones labelled “flushable”) and sanitary items.¹ Older drains add roots, scale, debris and the occasional collapse.

Washing-up liquid won’t fix it. Thames Water warns that hot water and washing-up liquid don’t dissolve fats and oils, so a grease blockage isn’t cleared that way — it can cool, harden and stick further along the pipe.² Chemical drain cleaners and boiling water tend to shift a grease problem along rather than remove it; a plunger, rods or professional jetting is the reliable fix.

Is it even yours to clear? Thames Water’s rule of thumb is that if the blockage is inside your property boundary it’s yours, and that the tell-tale signs it’s your blockage are that your neighbours aren’t having drain problems and your property doesn’t share a drain with others.¹ If several homes are affected, or it’s backing up beyond your boundary, it points to a shared or public sewer — see below before you pay anyone.

How it’s actually cleared. A drainage plumber should first check whether only one fitting is affected or whether several — toilets, sinks and outside gullies — are backing up, and look in the nearest inspection chamber, before deciding whether it needs rods, jetting or a call to Thames Water. A plunger or drain rods handle a simple blockage; grease and recurring blockages usually need high-pressure water jetting; and for repeat blockages a CCTV drain survey can confirm roots, displaced or collapsed joints, poor fall or fat build-up instead of repeatedly clearing the same symptom.

Whose drain is it in Kensington & Chelsea — and the basement problem

Combined sewers are the borough’s signature drainage issue. RBKC states that foul and surface sewers are generally combined in Kensington and Chelsea,³ so in heavy rain the same pipes carry rainwater and foul flows — and when they surcharge, the borough’s many basement and lower-ground flats are where drains back up first. That kind of back-up often isn’t a blockage in your drain at all.

Who’s responsible for what. Thames Water says you’re responsible for the waste pipes within your boundary that serve only your home, while it owns and maintains the public sewers under roads and footpaths, and any sewers or lateral drains you share with neighbours — even where those run under your garden or driveway.⁴ So before paying for a clearance, check with Thames Water whether the blockage is on your own drain, a shared one, or the public sewer — because a shared or public-sewer problem is theirs to fix, not yours.

Who to call. RBKC advises reporting flooding from toilets, sinks, drains or a sewer manhole to Thames Water on 0800 316 9800 (24-hour), and a blocked road gully to the Council’s Streetline on 020 7361 3001.⁵ If you’re a Council tenant, report it to RBKC Housing Management on 0800 137 111.⁶

Shared stacks in flats. In mansion blocks and converted houses, a blockage in a shared soil stack can affect several flats at once. If more than one flat on the same stack is backing up — with gurgling wastes or smells across more than one floor — it’s a shared-stack problem rather than one flat’s fault, which makes it a block-managed matter, with the managing agent or freeholder arranging access and the clearance.

Food premises and grease. Food premises around King’s Road, Earl’s Court Road and Portobello Road can add fats, oils and grease pressure to nearby drains and shared systems — that’s commercial territory (Commercial Plumbing), but it’s worth knowing if you’re on a shared run near a parade of restaurants.

Hard water. Thames Water confirms its region-wide water is hard, and scale can contribute to narrowing or roughness in older pipework.⁷

Getting to you. The whole borough is inside the London ULEZ,⁸ and RBKC says there’s no uncontrolled parking anywhere in the borough.⁹

Safety first

Treat backed-up sewage as a health hazard. Government public-health guidance is to wash your hands thoroughly with warm water and soap after any contact with flood or waste water, cover cuts and sores with waterproof plasters, and be careful with electrics and gas if they may have got wet — not turning them back on until a qualified person has checked them.¹⁰ Keep children and pets away from the affected area, and don’t use the toilet or sink that’s backing up until it’s cleared.

Water and electrics. Don’t touch backed-up water that’s near sockets, the consumer unit or appliances; switch the power off at the consumer unit only if it’s safe to reach.

If you ever smell gas, that’s a separate emergency: leave the property and call the National Gas Emergency Service on 0800 111 999 from outside — full steps are on our emergency plumber page.¹¹ The same number covers suspected carbon monoxide, which the HSE notes is colourless and odourless and can come from any poorly-burning combustion appliance.¹²

Find a verified drainage plumber by district

What blocked drains tend to look like across the borough’s main areas:

• Chelsea & World’s End (SW3, SW10): riverside and lower-ground flats near Chelsea Embankment where combined-sewer surcharge backs drains up into basements in heavy rain; on the World’s End and Cremorne estates, repairs route through RBKC.
• Kensington & Holland Park (W8, W14 edge): period houses and mansion flats with old, often shared, drainage runs, where a blockage can be a shared-stack or lateral-drain issue rather than one home’s.
• Notting Hill & Ladbroke Grove (W11, W10): basement flats around Portobello Road and Ladbroke Grove where heavy rain and combined sewers interact, making back-ups a recurring lower-ground problem.
• North Kensington & Notting Dale (W10): estate blocks with shared soil stacks where one blockage affects several flats, and the clearance is coordinated through the landlord or managing agent.
• South Kensington & Earl’s Court (SW7, SW5): dense conversions, hotels and restaurants around Cromwell Road and Earl’s Court Road, where food premises and grease put extra load on shared and public sewers.
• Brompton (SW3, SW7): mansion-flat blocks along the Brompton Road / Old Brompton Road corridor with shared waste stacks, where a blockage is often communal rather than confined to one flat.

What it costs

There’s no official price list for drain clearance, and we don’t publish invented “average” rates — though Thames Water does note that a blocked pipe at home is the owner’s to fix and can cost more than £200.² What’s honest is to set out what drives the cost.

These are general cost factors, not regulated rates, not market data and not a published cost survey. Ask whether the price is for a clearance only or includes a camera survey and any repair — and watch for cheap “from £X” call-outs that don’t cover finding the cause of a recurring blockage. Our How to Read a Plumbing Quote guide and London Plumbing Costs guide explain what to check.

Frequently asked questions

Why verified plumbers — not a general directory

A “drains cleared from £X” advert is easy to find — and easy to regret when the blockage comes straight back because no one looked for the cause, or when a quick rod was billed as a survey. That’s why every drainage plumber listed here is checked before going live and re-verified, rather than simply accepted, with their methods shown on the listing.

We confirm the business is legitimately trading and verify the named contact, we check evidence of public liability insurance, we review feedback and reputation from around the web, and we confirm they cover Kensington & Chelsea’s W8, W10, W11, W14, SW3, SW5, SW7 and SW10 postcodes before a profile is approved. Where drainage work touches the boiler or gas pipework, we confirm Gas Safe registration directly with the Gas Safe Register. For work on your water supply and fittings, you can also look a plumber up yourself on WaterSafe, the free, water-industry-backed national register.

Profiles may be suspended or removed if credentials lapse or credible concerns are raised — see the full verification process →. And there’s no customer middleman fee: enquiries go directly to the plumber.

Related areas

Verified plumbers across Kensington & Chelsea’s neighbourhoods, including:

• Brompton
• Chelsea
• Earl’s Court
• Holland Park
• Kensington
• Ladbroke Grove
• North Kensington
• Notting Hill
• South Kensington
• World’s End

Related services

Other verified plumbing services in Kensington & Chelsea:

• Emergency Plumber in Kensington & Chelsea
• Burst Pipes in Kensington & Chelsea
• Leak Detection in Kensington & Chelsea
• Toilet Repairs in Kensington & Chelsea
• Tap Repair & Installation in Kensington & Chelsea
• General Plumbing in Kensington & Chelsea
• Bathroom Plumbing in Kensington & Chelsea
• Kitchen Plumbing in Kensington & Chelsea
• Washing Machine & Dishwasher Installation in Kensington & Chelsea
• Boiler Repair in Kensington & Chelsea
• Boiler Installation in Kensington & Chelsea
• Boiler Servicing in Kensington & Chelsea
• Central Heating Repair in Kensington & Chelsea
• Commercial Plumbing in Kensington & Chelsea

Related guides

• London Plumbing Costs & Compliance Guide 2026
• How to Read a Plumbing Quote
• Victorian Terrace Plumbing Guide — London 2026
• London Hard Water — Homeowner & Landlord Guide

A blocked drain is two questions at once: what’s causing it, and whose drain it actually is — because the answer decides who pays. Sort that first, then use the verified listings above to find a checked drainage plumber for Kensington & Chelsea.

Contact verified drainage plumbers in Kensington & Chelsea ↑

← Back to all plumbing services in Kensington & Chelsea

Last reviewed: June 2026 by Adiel Khan — SFEDI-accredited business advisor, 20+ years’ experience (South East Enterprise Ltd) and operator of VerifiedPlumbers. LinkedIn ↗

This page is checked for compliance and regulatory accuracy against the bodies cited on it (Thames Water, RBKC, GOV.UK, National Gas, HSE, Gas Safe Register and TfL). Source links are provided within this page where relevant.

Sources & further reading

1. Thames Water — Blockages and blocked drains (signs of a blockage; three Ps; FOG, wipes and sanitary items; in-home responsibility test)
2. Thames Water — Fats, oils and grease (hot water and washing-up liquid don’t dissolve fats/oils; a blocked pipe at home can cost more than £200)
3. RBKC — Drainage and flooding (foul and surface sewers generally combined)
4. Thames Water — Sewer pipe responsibility (you’re responsible for pipes within your boundary serving only your home; Thames Water owns public sewers and shared sewers/lateral drains, even under your garden or driveway)
5. RBKC — Dealing with flooding (Thames Water 0800 316 9800; Streetline 020 7361 3001)
6. RBKC — Housing repairs (Housing Management 0800 137 111)
7. Thames Water — Hard water (region-wide hard water)
8. Transport for London — Ultra Low Emission Zone (all London boroughs; £12.50 daily charge)
9. RBKC — Guide to parking (no uncontrolled parking areas in the borough)
10. GOV.UK — Flooding and health: advice for the public (wash hands after contact with waste water; cover cuts; care with electrics and gas)
11. National Gas — Emergency contacts (0800 111 999; gas-emergency steps)
12. HSE — Carbon monoxide awareness FAQs (CO colourless and odourless; from any poorly-burning combustion appliance)
13. Gas Safe Register (official list of engineers qualified to work legally on gas)
14. WaterSafe (free water-industry-backed register of approved plumbers)