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A rising water bill, damp with no obvious source, or a leak you can hear but can’t find in your Tooting home? This page connects you with verified, insured leak-detection specialists covering SW17 who trace hidden leaks without tearing the place apart.
✅ Checked before listing — identity, insurance, trading presence, Gas Safe (where relevant).
✅ Workmanship guarantee badges on listings — 1, 3, 6 or 12 months.
Leak detection is quoted per job — a specialist will confirm the method and price before starting, and there’s no middleman fee on your enquiry. A hidden leak that reaches electrics should be treated as an emergency — see Emergency Plumber.
→ Contact a verified Tooting leak-detection specialist ↓ — scroll to the verified list below.
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Use the search above to find a local expert
Use the search above to find a local expert.
Coverage: SW17 — Tooting Broadway, Tooting Bec, Upper Tooting, Furzedown and the Tooting Common area — and the SW17 borders with Balham (SW12), Streatham (SW16), Earlsfield (SW18) and Colliers Wood (Merton).
What this covers: hidden leaks under floors, in walls, behind tiling and in ceilings; leaking underground supply pipes; unexplained damp, mould or rising water bills; and locating a leak precisely before any repair.
Not sure which page you need? If the water’s coming from a pipe you can see, start with Burst Pipes; if it’s a full-blown “stop everything” emergency, Emergency Plumber; if a drain or toilet is backing up, Blocked Drains.
Costs: detection is priced per job by method — see What it costs ↓ for an editorial estimate.
Availability: the verified specialists above set their own hours; most book a survey before quoting a repair.
Jump to: Signs of a hidden leak ↓ · How leaks are found ↓ · Whose leak is it? ↓ · Tooting’s older stock ↓ · By district ↓ · What it costs ↓ · FAQs ↓
Signs of a hidden leak
Hidden leaks rarely announce themselves. The usual clues are a water bill that’s crept up for no reason, a patch of damp or mould that keeps coming back, a musty smell, warm spots on a floor (a hot-water pipe), the sound of running water when everything’s off, or a boiler that keeps losing pressure. Any one of these on its own can be innocent; together, or persisting, they point to water escaping somewhere you can’t see.
The reason to find it precisely — rather than start opening up floors and walls — is cost and disruption. A specialist locates the leak first, so the repair is targeted. It also matters because a slow hidden leak can quietly damage structure, finishes and, in a Tooting flat or terrace conversion, the property below.
How leaks are found
A proper survey starts with simple tests before specialist equipment: check the meter with outlets closed, confirm which isolation valves change the loss, and test the incoming cold supply, hot-water side and sealed heating circuit separately. Acoustic listening and pressure testing work best on pressurised runs; tracer gas can help on difficult sections; moisture meters map spread. Thermal imaging relies on a temperature difference, so it is most useful for hot-water or heating leaks and may not identify a cold-water leak behind an insulated or thermally uniform surface.
The survey outcome should record the circuits and isolations tested, readings, photographs, the likely source and access point, and the confidence or limitations of the conclusion. Trace, access, pipe repair, drying and making-good should be identified as separate scopes. If the evidence is inconclusive, the report should say what further test or controlled opening is needed rather than present a guess as a confirmed location.
Whose leak is it?
Where the leak sits decides who pays — and there’s a specific rule worth knowing about your supply pipe.
Inside the boundary, the private supply pipe and internal pipework are normally the owner’s responsibility. Thames Water maintains the main and communication pipe up to the boundary and explains the owner’s duty to arrange repair of a confirmed private leak.1 In a rented property, the landlord is generally responsible for the water installations within section 11, subject to the tenancy, ownership of the fitting and tenant-caused damage; council tenants use Wandsworth’s repair route.23 In a leasehold flat, the lease and pipe location determine whether the leaseholder, freeholder or managing agent controls the repair.
Why Tooting’s older stock makes leaks harder to find
The construction and service route need checking at the individual property. A terrace or conversion may have buried or boxed-in pipework, a shared incoming supply or crossing branches; a managed flat may depend on access to a communal riser. None of those features should be assumed from the postcode alone, but each changes the isolation plan and the amount of access required.
Age can raise a lead-pipe question. Thames Water notes that homes built before 1970 are more likely to have lead supply pipework and explains the split between the private and company sections.4 Thames Water also confirms that its regional supply is hard, but hardness alone does not establish pinholing, stressed joints or the cause of a hidden leak; the failure must be diagnosed from pipe material, condition, pressure and the actual leak point.5
In a Broadway flat above a shop, water may appear in the commercial ceiling while the source is inside another flat or a communal riser. The specialist should document the evidence, make the affected area safe where possible and involve the freeholder or managing agent for communal access. An insurer or property manager may request a clear report with test results, photographs and a recommended access point; cover and evidence requirements must be checked against the individual policy or management process.
Find a verified specialist by district
Tooting Bec, Upper Tooting & Furzedown (SW17) — houses and conversions where the survey checks whether the supply is private or shared, which circuits can be isolated separately and what surfaces actually conceal the route.
Tooting Broadway — flats above shops and other homes, where evidence may need to distinguish an internal branch from a communal riser and support access through the managing agent.
The Common & Graveney side — lower-lying ground where damp can have more than one cause; a specialist rules the plumbing in or out before you assume the worst.
Converted flats & maisonettes — where pipework is concealed beneath tiled or solid-floor areas, the survey narrows the access point before finishes are opened.
If your property sits near the SW17 boundary at Balham, Streatham, Earlsfield or Colliers Wood, confirm your postcode is SW17 and within Tooting before booking.
What it costs
Leak detection is priced by method and access, and is separate from the repair itself. The figures below are an editorial estimate only to help you sense-check a quote — they are not regulated rates, not market data, and not a published cost survey. Confirm the price before work starts, and see How to Read a Plumbing Quote and the London Plumbing Costs & Compliance Guide 2026.
| Leak-detection job (indicative) | Typical range |
|---|---|
| Non-invasive leak-detection survey | £150–£350 |
| Underground supply-pipe leak location | £200–£450 |
| Trace and access (locate + expose) | quoted per job |
| Repair once located | quoted per job |
Home-insurance cover for trace and access varies by policy, so check the wording and any evidence requirements before authorising access. Tooting is inside the London-wide Ultra Low Emission Zone, which Transport for London operates across all London boroughs; a non-compliant vehicle incurs the daily ULEZ charge.6 Tooting (SW17) sits outside the central London Congestion Charge zone.
VerifiedPlumbers is a directory that connects you with verified plumbers; it doesn’t carry out the work itself, and enquiries go directly to the specialist with no middleman fee.
Frequently asked questions
Common signs are a rising water bill, damp or mould that keeps returning, a musty smell, warm patches on the floor, the sound of running water when everything’s off, or a boiler losing pressure. A detection survey confirms whether it’s a leak and where.
The sequence normally combines meter and isolation checks, separate circuit tests, pressure or acoustic testing, moisture mapping and—where useful—tracer gas. Thermal imaging depends on a temperature contrast and may miss a cold-water leak; the report should state the method, findings and confidence before any surface is opened.
If it is on the private supply pipe or internal pipework, the owner normally arranges the repair. In rented or leasehold property, responsibility also depends on the tenancy or lease, ownership of the fitting, whether damage was tenant-caused and whether the pipe is communal.
If the property was built before 1970, a lead supply pipe is possible, but construction date and pipe material should be checked rather than inferred from the neighbourhood. Thames Water explains responsibility for the private and company sections.
Sometimes, but cover, limits and evidence requirements vary. Check the policy and ask whether the insurer needs approval, photographs or a written detection report before access work begins.
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Related services in Tooting
- Burst Pipes in Tooting — a pipe you can see has split
- Emergency Plumber in Tooting — a leak you can’t stop
- Blocked Drains in Tooting — a drain or toilet backing up
- Bathroom Plumbing in Tooting — hidden leaks behind tiling
- All plumbing services in Tooting — the full directory
Related guides
- London Hard Water Guide — where hardness may affect fittings and hot-water components
- How to Find Your Stop Tap — isolate before a repair
- London Plumbing Costs & Compliance Guide 2026
Finding a hidden leak precisely keeps access proportionate. The useful deliverable is a defensible record of what was tested, where the source is most likely to be, what remains uncertain and which access or repair should follow. The verified leak-detection specialists above cover SW17 across Tooting, with identity and insurance checked before listing.
→ Contact a verified Tooting leak-detection specialist ↑ — see the verified list above.
Last reviewed: July 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 and regulations cited on it — Thames Water, the Landlord and Tenant Act 1985, the London Borough of Wandsworth and Transport for London. Source links are provided within this page where relevant.
Sources & further reading
1. Thames Water — Pipe responsibility (owner responsible for the supply pipe and internal pipework; four weeks to repair a confirmed leak). https://www.thameswater.co.uk/help/water-and-waste-help/leaks/pipe-responsibility
2. Landlord and Tenant Act 1985, section 11 (landlord repairing covenant — water installations). https://www.legislation.gov.uk/ukpga/1985/70/section/11
3. Wandsworth Council — Council tenants: request a repair (out-of-hours 020 8871 8999). https://www.wandsworth.gov.uk/council-tenants-request-a-repair/
4. Thames Water — Lead pipe replacement (homes before 1970 more likely to have lead; owner responsible for the private section). https://www.thameswater.co.uk/help/water-and-waste-help/water-quality/lead-pipe-replacement
5. Thames Water — Hard water (all water in the region is hard). https://www.thameswater.co.uk/help/water-and-waste-help/water-quality/hard-water
6. Transport for London — Ultra Low Emission Zone (operates across all London boroughs). https://tfl.gov.uk/modes/driving/ultra-low-emission-zone