Leak Detection in London — Pinpoint Hidden Leaks Without Tearing Up Your Home
Acoustic, thermal and tracer gas methods to locate leaks with pinpoint accuracy
A hidden water leak is one of the most destructive problems a London property can face. Whether it’s a concealed pipe leaking behind a solid wall, a slab leak under a concrete floor, or an underfloor heating circuit losing pressure, the damage builds silently for weeks or months before becoming visible. 247 Plumber London uses professional non-invasive leak detection equipment — acoustic listening devices, thermal imaging cameras, and tracer gas systems — to locate the source of a leak precisely, minimising the need for exploratory damage to your property. We operate across all London boroughs, 24 hours a day, 7 days a week.
Types of Leaks We Detect in London
Concealed Pipe Leaks
Pipes running within walls, under floors, or in ceiling voids can develop small leaks at joints, fittings, or due to pipe corrosion. These leaks may go undetected for months, causing progressive water damage to surrounding plasterwork, timber, and insulation. Damp patches, peeling paint, or wallpaper lifting away from walls are common signs. We locate the exact point of the leak before recommending any repair, avoiding unnecessary damage to your decorations.
Underfloor Heating Leaks
Underfloor heating systems — both water-based (wet UFH) and pipe-in-screed — can develop micro-leaks that cause pressure loss without producing visible water at the surface. The leak may be at a fitting, a pipe joint, or due to damage to the pipe itself. Thermal imaging reveals cold spots in the floor where water is escaping, allowing us to pinpoint the fault without breaking up the entire screed.
Slab Leaks
A slab leak occurs when pipework beneath a concrete slab or ground floor develops a fault. Hot or warm spots on the floor surface, unexplained increases in water bills, or low pressure can all indicate a slab leak. Acoustic listening equipment detects the sound of water escaping under pressure through concrete, guiding us precisely to the fault location.
Pool Leaks
Swimming pool and hot tub leaks can be difficult to distinguish from evaporation. We use pressure testing and dye testing to identify whether a pool is losing water through a structural fault, and tracer gas or acoustic methods to locate the precise failure point in pipework.
Roof and External Leaks
Water entering through roofs, guttering, or external walls often travels some distance before appearing as a damp patch internally, making the entry point difficult to identify visually. Thermal imaging reveals temperature differentials caused by moisture ingress, helping identify the source before significant damage occurs.
Leak Detection Methods We Use
Acoustic listening equipment: Highly sensitive microphones and ground probes amplify the sound of water escaping from pressurised pipework, allowing us to pinpoint leaks beneath solid floors and within walls without drilling or exploratory cutting.
Thermal imaging camera: Moisture causes temperature differentials invisible to the naked eye. Thermal cameras reveal these patterns in real time, identifying damp areas within walls and floors non-invasively.
Tracer gas detection: A harmless mix of hydrogen and nitrogen is introduced into the pipework. The gas escapes at the point of the leak and is detected at the surface by a sensitive probe, providing extremely accurate location — precise to within centimetres.
Pressure testing: The affected circuit is isolated and pressure tested to confirm a leak exists and to quantify pressure loss, helping us understand the severity before selecting the most appropriate detection method.
How We Handle Leak Detection in London
- Initial consultation: We discuss the symptoms — damp patches, pressure loss, rising water bills — and form a hypothesis about the likely cause and location.
- Access and preparation: We isolate the relevant circuit and prepare for testing, protecting your property throughout.
- Detection: Using acoustic, thermal, or tracer gas equipment as appropriate, we systematically locate the leak.
- Confirmation: The finding is confirmed and the precise location marked before any repair work begins.
- Repair recommendation: We advise on the most appropriate repair method — which may range from a simple pipe joint repair to a section replacement.
- Repair and test: On your instruction, we carry out the repair and re-test the circuit to confirm the leak is resolved.
Leak Detection Across London
We carry out leak detection throughout London, covering Westminster, Camden, Islington, Hackney, Tower Hamlets, Southwark, Lambeth, Wandsworth, Greenwich, Lewisham, Bromley, Croydon, Sutton, Merton, Kingston upon Thames, Richmond, Hounslow, Ealing, Brent, Harrow, Barnet, Enfield, Haringey, Waltham Forest, Newham, Redbridge, Barking, Havering, Kensington, Fulham, Clapham, Brixton, and Peckham.
Why London Customers Choose Us
- Gas Safe registered engineers (ask to see the card on arrival)
- Upfront pricing — agreed before we start, no hidden extras
- Competitive Rates
- Fully insured and DBS checked
- 24/7 service including bank holidays
Frequently Asked Questions
Can you find a leak without breaking my floor or walls?
In the majority of cases, yes. Our acoustic, thermal, and tracer gas methods are non-invasive — they allow us to locate a leak precisely without exploratory damage. Once we’ve identified the exact location, any opening-up required for the repair is kept to a minimum.
How accurate is leak detection?
Tracer gas detection is accurate to within a few centimetres. Acoustic detection is slightly less precise but still narrows the location to a small area. Thermal imaging identifies areas of moisture ingress very effectively. In practice, we typically open up the minimum possible area to access and repair the leak.
How much does leak detection cost?
Cost depends on the method required and the complexity of the system. We provide an upfront price before starting. Leak detection is an investment — the cost of water damage left unaddressed is typically far greater than the detection fee.
Can you detect a leak in an underfloor heating system?
Yes. Thermal imaging is particularly effective for underfloor heating leaks, identifying cold spots in the floor where heat is being disrupted by water loss. Tracer gas can also be used where thermal imaging is inconclusive.
What are the signs of a hidden water leak?
Common signs include unexplained damp patches or staining on walls, ceilings or floors; peeling wallpaper or paint; musty or mouldy smells; a water meter that continues to move when all taps are off; low water pressure; and unexplained increases in your water bill.
Will my insurance cover the cost of leak detection?
Many home insurance policies include trace and access cover, which pays for the cost of finding a concealed leak and making good any surfaces opened up during the process. Check your policy documents or call your insurer before we start — we can provide documentation to support your claim.
How long does leak detection take?
A straightforward leak detection visit typically takes 1-3 hours. More complex situations — large properties, extensive systems, or multiple possible leak sources — may take longer. We’ll give you an honest estimate before we start.
Can you repair the leak once you’ve found it?
Yes. In most cases we can carry out the repair on the same visit. We’ll confirm the approach and cost before starting any repair work.
Can you detect leaks in concrete slabs?
Yes. Acoustic listening equipment is specifically designed to detect water escaping through pressurised pipes beneath concrete. The sound travels through the slab and is amplified by our equipment, allowing us to identify the leak location without breaking up the floor speculatively.
My water bill has gone up — is it definitely a leak?
A rising water bill with no obvious explanation is a strong indicator of a hidden leak. Turn off all taps and water-using appliances and check whether your water meter is still moving — if it is, water is escaping somewhere. Call us and we’ll investigate.
Suspect a Hidden Leak in Your London Property?
Available 24/7 across all of London
Email: info@247plumberlondon.co.uk