Responsibility for a blocked drain depends on whether the pipe is a private drain, lateral drain or public sewer — not simply whether it’s inside or outside your boundary. Croydon residents need to know which is which before paying a private contractor.

Engineers listed here cover Croydon CR postcodes for drain unblocking, CCTV surveys and repairs.

✅ Gas Safe registration checked against the Gas Safe Register where applicable ✅ Insurance and business identity and contact details verified
✅ Verified by our 16-point process (see how we verify plumbers →)
✅ Covering CR0, CR2, CR5, CR7, CR8, SE25 & SW16

Who should I call first?

• Croydon Council tenant → call 020 8726 6100
• Only your property affected, inside your boundary → call a private drain engineer
• Neighbours also affected, shared drain, external manhole, or water backing up → call Thames Water on 0800 316 9800 — they may clear it at no cost if it’s theirs²
• Not sure? → Thames Water can assess first

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Every listing is verified at time of listing — Gas Safe registration checked against the Gas Safe Register where applicable, evidence of public liability insurance checked, business identity and named contact validated. No paid placements go live without verification — listing comes after checks, not before.

Simple blockages often resolve within the ranges in the cost table below. Recurring blockages or structural faults may need a CCTV survey and repair. No call centres, no middlemen — you contact the engineer directly, describe the symptoms, location and access, and confirm whether a visit is needed and likely cost before booking. You choose whether to proceed.

Who is responsible for a blocked drain in Croydon

Drainage responsibility depends on the type of pipe — and getting this wrong can mean paying for a job Thames Water would have done.

Private drains (your responsibility): drains that serve only your property are usually your responsibility until they connect to another drain or a public sewer. Croydon Council confirms a drain is the property owner’s responsibility until it connects to either someone else’s drain or to a public sewer.¹

Lateral drains and shared/public sewers (Thames Water’s responsibility): pipes shared with neighbours or classed as public sewers or lateral drains are usually Thames Water’s responsibility. Thames Water confirms it owns, maintains and repairs public sewers under roads and footpaths, and is responsible for sewers shared with neighbours, even where they run under your garden or driveway.²

If you’re not sure: Croydon Council advises that if water is “backing up” into your toilet, sink or bath and causing flooding, contact Thames Water on 0800 316 9800.¹ Thames Water can assess whether the blockage is theirs and clear it if it falls within their responsibility.

Council tenants: report blocked drains to Croydon Council’s housing repairs service on 020 8726 6100 — not to Thames Water or a private contractor.³

When to call a private drainage engineer

A private engineer is the right call when:

• the blockage is on a private drain serving only your property
• Thames Water has confirmed the blockage isn’t theirs
• you need a CCTV survey, drain repair or recurring blockage investigation that goes beyond standard clearance
• If the blockage affects multiple properties, an external manhole or shared pipework, contact Thames Water before booking a private contractor — it may fall within their responsibility.²

Common signs of a blocked drain include slow-draining sinks or baths, gurgling toilets, bad smells from drains or gullies, water backing up into the property, or wastewater pooling in outside gullies.

For a recurring blockage in the same drain, a one-off clearance often won’t be enough — a CCTV survey will identify whether tree roots, broken pipework, scale or a structural issue is the underlying cause.

Common causes of blocked drains in Croydon homes

Croydon Council confirms drain blockages are preventable, and lists the most common causes as pouring cooking fat, oils and grease down drains, detergent scaling (particularly in hard water areas), flushing paper and cloth products such as nappies, sanitary towels, cotton wool buds and newspapers down toilets, and pouring cement or plaster down drains.⁴

Two further causes commonly reported by drainage engineers in older properties:

• Tree root intrusion — older clay and pitch fibre drainage runs are vulnerable to root ingress, particularly in Victorian and Edwardian terraces with mature street trees nearby. Roots enter through pipe joints and grow inside the drain until flow is restricted.
• Pipe collapse or displacement — clay drainage that has been disturbed by ground movement, building works or tree roots can crack, sag or fully collapse, causing repeated blockages even after clearance.

Both typically need a CCTV survey to confirm and a no-dig repair (patch lining) or excavation to fix.

CCTV drain surveys

A CCTV survey uses a small camera on a flexible rod to inspect the inside of a drain. It’s used to:

• find the exact location and cause of a recurring blockage
• identify cracks, displacement or collapse before excavating
• confirm whether tree roots have entered the run
• may be used as supporting evidence for an insurance claim
• survey drains before purchase of a property (pre-purchase survey)

A clear CCTV report should include the location of any defects (in metres from the access chamber), a written summary of findings, and a recommendation for repair or further investigation.

Drain repair — no-dig vs excavation

If a CCTV survey identifies broken or collapsed pipework, repair is the next step.

No-dig repairs — patch lining or full pipe lining — install a resin-coated liner inside the existing drain. The liner cures in place, sealing cracks or short collapses without excavation. Faster, less disruptive and usually cheaper than digging.

Excavation — sometimes the only option for severe collapse, badly displaced sections, or where the drain run isn’t accessible to lining equipment. More disruptive and usually more expensive, but necessary when no-dig isn’t viable.

A drainage engineer should explain which approach is appropriate for the specific defect and quote both where relevant.

Hard water and drainage in Croydon postcodes

Croydon is within Thames Water’s supply area, where water is generally hard. Thames Water confirms hard water can lead to limescale build-up on household appliances and fittings⁵ — and detergent scaling in hard water areas is one of the causes of drain blockages flagged by Croydon Council.⁴

Scale combines with grease and soap residue inside drains over time, narrowing the bore of the pipe and reducing flow. High-pressure water jetting is often used for clearing scale-and-grease build-up of this type.

Council tenants in Croydon — blocked drain repair route

If you live in a Croydon Council home, blocked drain repairs go through the council, not a private engineer.

Croydon Council confirms that, if a drain at a council property is blocked, tenants should contact the housing repairs service on 020 8726 6100.⁴

For emergency repairs — a serious blockage causing internal flooding, for example — the council’s 24/7 contact centre is 020 8726 6101.⁶

Private tenants in Croydon — blocked drain responsibility

Croydon Council confirms that for blocked drains in privately rented homes, the landlord is generally responsible and should arrange for remedial works to be carried out.⁴

Report the blockage to your landlord or letting agent first, in writing where possible.

Croydon Council advises private tenants that for an urgent repair they should contact their landlord or agent immediately and follow the call up with a letter or email.⁷ If your landlord does not respond, Croydon Council’s Private Sector Housing Team can intervene on 020 8760 5476.⁷

Keep photographs, texts and emails — the council will ask to see evidence of what you reported and how your landlord responded.⁷

What blocked drain work costs in Croydon

Indicative estimates based on recent London jobs and market observations (2025–2026), not regulated rates — no official pricing data exists for private drainage work. Always confirm pricing before work begins. Actual costs vary by access, blockage location, equipment required and severity. VAT may apply.

Confirm whether the callout includes guaranteed clearance or diagnostic only, and whether VAT and any access work are included.

See the full London Plumbing Costs Guide →

Why verified engineers — not a general directory

Engineers listed here are verified at time of listing — the checks below are completed before the profile goes live.

What we check before an engineer is listed in Croydon:

• Identity and trading details — we confirm the business is legitimately trading, verify the registered business name, and verify the business identity and named contact behind the listing. No anonymous profiles go live.
• Gas Safe registration — where a plumber offers gas work, we confirm their Gas Safe registration number directly with the Gas Safe Register, checked against the engineer’s name and the specific gas work categories they are qualified to carry out.
• Public liability insurance — every listed engineer is required to hold public liability insurance, and evidence of cover is checked at the point of listing.
• Service coverage — we confirm the engineer actually covers Croydon CR postcodes before approving the profile.

Profiles are removed if credentials lapse or credible concerns are raised.

See the full verification process — Gas Safe, insurance, identity and service area checks →.

No middleman fees — every lead goes directly to the engineer.

We limit listings per borough so every engineer gets fair, equal visibility.

Frequently asked questions — Blocked Drains Croydon