A damp patch, a rising water bill, or a letter from Thames Water — leak detection locates the source first, and repair is quoted separately once confirmed. If Thames Water confirms a leak on your property, they may require repair within four weeks under the Water Industry Act 1991.¹

Engineers listed here cover Croydon CR postcodes. Wet heating pipework, radiators and valves don’t require Gas Safe registration; gas appliances, gas pipework or flues do.

✅ 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

What kind of leak are you dealing with?

• Damp patch, stain or wet floor indoors → internal leak — your responsibility
• Wet patch in garden or driveway → supply pipe leak — your responsibility²
• Leak in the road or pavement → report to Thames Water on 0800 316 9800²
• Thames Water letter about a leak at your property → typically four weeks to arrange repair¹
• Heating pressure dropping or boiler topping up repeatedly → heating engineer to diagnose; gas components need Gas Safe

If the leak source is clearly visible and accessible, a standard plumbing repair may be enough — leak detection is for hidden or unclear sources.

Get a Verified Leak Detection Engineer in Croydon Now →

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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.

Non-destructive tracing is used to locate leaks before opening floors or walls where possible:

• acoustic listening
• thermal imaging
• tracer gas
• moisture testing

Detection is a paid diagnostic step. Once located, simple repairs may be done on the same visit; bigger jobs are quoted separately — ask whether the detection fee is deductible if the same engineer does the repair. No call centres, no middlemen — you contact the engineer directly and agree scope and price before booking.

Before any engineer begins gas work, ask to see their Gas Safe ID card and check the back for the specific work categories they are qualified for.

Who’s responsible for what — supply pipes and internal plumbing

Water leak responsibility depends on where the leak is. Getting this wrong can mean paying for a job Thames Water would have handled.

Your responsibility as a homeowner:

Thames Water confirms that as a homeowner, you’re responsible for the water supply pipe running from the property boundary into your home — usually under your garden or driveway — and all your internal pipes, appliances and fittings (toilets, taps, showers, water tanks, washing machines).²

Thames Water’s responsibility:

Thames Water confirms it is responsible for the water mains that carry water around the region, and also for the communication pipe linking your supply pipe to the water mains.² If you see a leak in the road or pavement, report it to them.

Shared supply pipes: Thames Water confirms that where a single supply pipe serves two or more properties (common on terraced streets), the properties share joint responsibility for maintaining the shared part of the pipe.³

Tenants: Thames Water confirms that if you’re a tenant, your landlord is responsible for fixing leaks² — report the leak to your landlord or letting agent in writing as soon as possible.

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The four-week repair period — what happens if you don’t fix a confirmed leak

If Thames Water confirms a leak on your property, they may require you to arrange repair — typically within four weeks.¹

If the leak isn’t repaired in that period, Thames Water has powers to act under Section 75 of the Water Industry Act 1991, including carrying out the repair and recovering the cost from the property owner.¹ In an emergency, Thames Water may also turn off the supply until the leak is repaired.¹

In practical terms, the four-week period is a prompt to act — not a reason to panic. Book a leak detection engineer, get the location confirmed, and schedule repair. If you’re waiting on parts or access, tell Thames Water.

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Leak detection methods — what the engineer actually does

Leak detection often starts with non-destructive tracing methods — used to locate the leak before lifting flooring, taking down walls or excavating ground where possible.

• Acoustic listening equipment — amplifies the sound of water escaping from a pipe under pressure. Effective for supply pipe leaks and larger internal leaks.
• Thermal imaging — detects temperature differences where water has cooled or warmed an area. Good for hot-water leaks under floors and central heating leaks.
• Tracer gas — a non-toxic gas pumped into the pipe escapes at the leak point and is detected above ground. Often used for supply pipe leaks under driveways or lawns.
• Moisture meters and damp surveys — identify the wettest point in a wall or floor when the visible symptom (a damp patch) is not at the source.
• Pressure testing — isolates sections of pipework to confirm which branch is losing water.

Many leak detection visits include a written report identifying the location and likely cause, which can be used to plan repair or support discussions with insurers, landlords, managing agents or water companies. Repair is often quoted separately — ask whether the detection fee is deductible from repair costs if you book the same engineer. If the detection is being arranged for a third party, confirm in advance what documentation the engineer will provide.

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Hard water and leak risk 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 fittings.⁴

Over time, scale and internal corrosion can contribute to wear in fittings, tap washers, and connection points on appliances and cylinders. If your property has had repeated issues on hot-water fittings or appliances, ask the engineer whether scale may be a contributing factor.

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Council tenants in Croydon — leak repair route

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

Call 020 8726 6100 — or for emergencies, 020 8726 6101 (24/7).⁵

Croydon Council’s repair priorities confirm that water leaks affecting the structure or electrics of the property are classified as urgent.⁵

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Private tenants in Croydon — landlord obligations

Leaks in a rented property are the landlord’s responsibility to repair. Thames Water confirms that if you’re a tenant, your landlord is responsible for fixing leaks.²

Report the leak to your landlord or letting agent first, in writing.

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.⁶

If your landlord does not respond, Croydon Council’s Private Sector Housing Team can intervene on 020 8760 5476.⁶

Keep photographs, texts and emails — the council will ask to see evidence of what you reported and how your landlord responded.⁶

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What leak detection 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 leak detection. Always confirm pricing before work begins. Actual costs vary by access, method required, property layout and whether repair is included. VAT may apply.

Service	Typical range (London)
Internal leak detection (acoustic/thermal)	from £250
Supply pipe leak detection (external)	from £300
Full-property survey (multiple methods)	from £450
Repair of internal leak (simple, accessible)	from £150
Repair of supply pipe leak (excavation)	from £800
Supply pipe replacement (damaged pipework)	from £1,500

Confirm whether the detection fee is deductible from repair cost if the same engineer carries out both. Ask whether the quote includes making good (reinstating driveway, flooring, plaster).

See the full London Plumbing Costs Guide →

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Frequently asked questions — Leak Detection Croydon

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