24/7 Emergency Detection

Leak Detection London

A hidden leak can cause serious structural damage and mould within hours. You need it found and contained immediately.

How a detection visit is priced

Job	How it is charged	Time
Detection visit, whichever methods it ends up needing	One fixed fee, agreed at booking	Most homes, a single visit
Switching method when the first one goes quiet	Included, not a reason to charge again	Adds time to the same visit
Attendance at night, at a weekend or on a holiday	Out-of-hours band, stated before the engineer sets off	Any hour
Written record of what was found and where	Part of the visit	Issued after the survey
Putting the fault right	Quoted separately once the point is marked	Same visit where reachable

How each stage is charged, not a quote. The detection fee is fixed and agreed on the call, before an engineer travels.

Our engineers are on call 24/7, ready for immediate dispatch across London boroughs from Kensington to Canary Wharf. We specialise in fast, accurate location using advanced technology.

At the first sign of a damp patch on a ceiling, a persistent hissing sound, or a suddenly high water bill, call us. We'll locate the source so repairs can begin.

Unlike a general plumbing call-out that opens walls on a hunch, leak detection in London is a diagnostic survey: we pressure-test circuits, listen with acoustic kit, map temperature with thermal imaging, and use tracer gas when plastic pipe or screed mutes the sound. The goal is a single marked point you can repair without wrecking the room.

We work in Victorian terraces, mansion blocks, post-war semis and new-build towers across all 33 boroughs. Flat-to-flat disputes, spinning water meters and boilers that keep losing pressure are everyday jobs for us, not edge cases.

Our pricing is based on a fixed fee for the leak detection service. This covers the engineer's time and the use of specialist equipment to locate the leak. There are no hidden charges. See our pricing page for time bands and job types.

What you get

24/7 emergency response, including nights and weekends.
Advanced acoustic and thermal imaging equipment to find leaks without unnecessary damage.
Experienced in all London property types, from Victorian terraces to modern high-rises.
Immediate reporting of the leak's precise location to you and your plumber.
Focus on minimising water damage and disruption to your home.
Coverage across all London postcodes, from Hampstead to Greenwich.
No find, no fee on multi-method detection visits.
Optional insurer-ready trace and access reports with moisture mapping and photos.

How it works

A method, not a guess

Your Emergency Call

Call us any time. Describe the signs: rising damp, sounds, or meter activity. We dispatch the nearest available engineer.

Rapid On-Site Assessment

Our engineer arrives promptly. They listen to your concerns and examine the property for visible clues to narrow the search area.

Precise Technical Location

Using non-invasive tools like acoustic probes and thermal cameras, we pinpoint the exact source of the hidden leak behind walls or under floors.

Clear, Actionable Report

We show you the evidence, mark the leak location, and provide a detailed report so you or your plumber can make the repair immediately.

Before you book anyone

6 things to check before you book leak detection in London

A cheap hourly rate is not a cheap survey

An hourly rate is the most expensive way to buy a search, because nobody can tell you in advance how long a search is going to take. A hard-to-trace leak under screed can absorb a full day, and the meter keeps running whether or not anything is found. For a published reference point, Checkatrade records UK leak detection jobs across a spread of £80 to £1,600, with an average of £162, most jobs between £115 and £234, and hourly diagnostic rates of £95 to £145. Settle the shape of the deal before anyone arrives: a fixed fee agreed at booking cannot creep, whereas an open-ended hourly arrangement puts the whole risk of a difficult search on you.

Read the no-find-no-fee small print before you rely on it

Published terms from UK detection firms show how narrow some guarantees are: central heating leaks and incoming mains are often excluded entirely, pipes in ducting or beneath a membrane may be carved out, and one firm defines a leak as "found" once narrowed to a 5m x 5m area - roughly a whole room. Another only honours no-find-no-fee if you also pay them to do the intrusive access work. Ask three questions: does it cover heating circuits, how precisely must the leak be located, and are there strings attached to claiming it.

Ask what equipment is actually on the van

No single technology finds every leak. Thermal imaging shows surface temperature, not water; acoustic microphones struggle with slow drips; tracer gas needs the circuit drained down. A one-method operator who turns up with only a thermal camera will miss leaks the other methods would catch, then charge for a second visit. Before booking, ask the firm to list what they bring as standard. We carry acoustic gear, thermal imaging, tracer gas (5% hydrogen in nitrogen), moisture mapping and per-circuit pressure testing on every visit, because most stubborn leaks need two or three methods to cross-confirm.

The report decides whether your insurer pays

Most buildings policies include trace and access cover, which can reimburse the detection fee and the cost of opening up floors or walls. The limit varies enormously between policies and some basic tiers carry none at all, so read the figure off your own schedule rather than relying on a general one. But loss adjusters reject vague reports. A claim-ready document must state the cause and origin of the leak, the detection methods used, moisture readings across affected areas, and photographic evidence. Two important caveats from real claims: trace and access generally only pays where the escape of water has caused damage, and gradual wear or poor maintenance can void cover. Ask any firm to show you a sample report before booking.

Rule out the boiler before paying anyone to hunt pipes

A sealed heating system that keeps losing pressure does not always mean a hidden pipe leak. A failed expansion vessel produces identical symptoms with no water escaping anywhere, and public discussion regularly describe homeowners paying two or three separate detection firms before anyone thought to check the boiler itself. A competent surveyor should pressure test each circuit separately and eliminate the boiler's internal components first. If a firm quotes for full-property detection without asking about your boiler's behaviour, treat that as a red flag.

Check who is responsible before you spend a penny

Not every leak is yours to fix. The water company owns the communication pipe up to your property boundary; you own the supply pipe from the boundary inwards, though Thames Water and other suppliers often repair or subsidise a first external supply-pipe leak free of charge - ring them before commissioning a survey if your meter spins with everything off. In flats, leaks in communal risers or above your ceiling are usually the freeholder's or the neighbour's problem, so notify the managing agent in writing first. Booking detection for a pipe you do not own wastes the fee.

Compare like for like

Detection that ends in one marked spot, not a stripped room

The point of a detection visit is narrow: turn a wet ceiling into a single place you can open up. Judged that way, a lot of what is sold as leak detection fails, because it identifies a damp area rather than a source. The distinction sounds academic until you are looking at a room with the floor up and the leak still running somewhere underneath it.

What to check	A twenty minute damp-meter visit	A single-method survey	How we run the call
What you are left with	A reading confirming the area is wet, which you already knew, and a bill.	A general region, often described as a few square metres, which can mean a whole room.	A marked point. If we cannot get to a point, we say so rather than dressing up an area as a result.
Methods carried	A moisture meter and confidence.	One technology, excellent on the pipes that suit it and blind on the ones that do not.	Sound, heat, gas and pressure testing on the same visit, because most stubborn leaks need two of them to agree.
Switching approach mid-visit	Not possible. There is nothing to switch to.	Means a new appointment, a new fee and more days of water.	Part of the same visit at no extra charge. Changing method is normal work, not a new job.
Availability	Working hours, when the meter reading is easiest to take.	Booked days ahead, which is fine for a slow drip and not for a live leak.	Engineers on call through the night, with anything actively running put in front of the booked diary.
What you can rule out first	Nothing suggested. A survey is the product being sold.	Occasionally, depending on the surveyor.	The meter test, the stop tap test and the boiler gauge are all free and all yours to do. We will tell you how before you pay us anything.
Cost certainty	Cheap on the phone, then a recommendation for something dearer once they are in the room.	A fixed figure for one method, with the risk sitting on you if that method fails.	One fee for the detection visit, agreed before we travel, whichever methods it turns out to need.
After the source is found	Nothing follows. Locating was never really the plan.	Handover to another trade and another visit.	The repair is quoted on its own so you can see it plainly, and carried out on the same visit where the pipe allows.

From the forums

The questions that come up when a leak starts

London homeowners compare leak detection experiences in public discussion, and the same frustrations come up again and again: surprise bills, guarantees that evaporate in the small print, and insurance claims that stall on weak paperwork.

On public discussion's insurance board, homeowners confused by trace and access cover

A recurring thread pattern: a boiler loses pressure, the homeowner pays for detection expecting insurance to reimburse it, then discovers trace and access only responds where the escape of water has actually caused damage - and that faults inside the boiler, like a failed expansion vessel, are treated as maintenance and excluded. Posters routinely describe several paid visits before learning this. Our take: check your policy wording and the cause of the pressure loss before commissioning a survey, and use a firm whose report clearly separates insured damage from maintenance issues.

In Trustpilot reviews of national leak detection firms, customers on no-find-no-fee disputes

The sharpest complaints come from people who booked on the strength of a no-find-no-fee promise and were still billed - either because the firm identified the wrong leak and charged the full fee anyway, or because heating systems and mains pipes were quietly excluded from the guarantee. Reviewers consistently advise reading the terms page, not the homepage banner. Our take: a genuine guarantee should name its exclusions upfront and define what counts as finding the leak to a repairable point, not just a general area.

On public discussion's plumbing public discussion, homeowners whose leaks nobody could find

Multiple long-running discussions describe sealed-system pressure loss where two or three detection companies each charged a visit fee and found nothing, before a gas engineer eventually traced the problem to the boiler's expansion vessel - a fault that mimics a hidden leak without a drop of water escaping. Forum regulars now routinely tell posters to isolate circuits and check the vessel before paying for detection. Our take: per-circuit pressure testing at the start of a survey exists precisely to catch this, and any surveyor who skips it is guessing.

Across trade public discussion and cost-guide comment sections, homeowners comparing quotes

People report quotes for the same suspected leak varying by close to an order of magnitude, which is consistent with Checkatrade's published UK spread of £80 to £1,600. The consensus advice is that suspiciously cheap callouts are usually a foot in the door - either the hours multiply once the engineer is on site, or the cheap visit finds nothing and a pricier second survey is recommended. Our take: compare total fixed prices for a complete multi-method survey, not headline hourly rates, because the fixed number is the only one you can hold a firm to.

On housing and insurance public discussion, leaseholders dealing with leaks between flats

A steady stream of posts involves water coming through a ceiling from the flat above, with confusion over who commissions and pays for detection - the leaseholder, the neighbour or the freeholder's block policy. The practical consensus: notify the managing agent in writing immediately, because block buildings insurance with trace and access often covers the survey, and an independent report establishing the leak's origin settles arguments about liability. Our take: an insurer-ready report that pins down cause and origin is worth far more in a flat dispute than a plumber's verbal opinion.

Symptoms

Signs you need leak detection in London

Most hidden leaks announce themselves weeks before a ceiling collapses. Book detection when any of these show up. Waiting rarely makes the repair cheaper.

Unexplained damp patch on a wall, ceiling or floor that grows or darkens
Boiler pressure dropping every few days even after topping up
Water meter spinning when every tap and appliance is off
Hissing, running or dripping sounds with nothing on
Musty smell, peeling paint or mould in a room that should be dry
Suddenly high water bill with no change in household use
Warm or cold spots on a solid floor (underfloor heating circuit)
Water through a ceiling from the flat above, origin still unknown

What to do before the engineer arrives

1If safe, shut the internal stopcock to slow active damage.
2Photograph damp patches, meter readings and any staining for insurance.
3Clear access to the boiler, airing cupboard, stopcock and affected rooms.
4Note when the problem started and whether pressure drops overnight.
5Have your postcode, property type and insurer details ready if claiming.

When a leak is an emergency

Treat active flooding, water near electrics, a collapsing ceiling or a meter racing with everything off as urgent. Isolate the supply if you can, move people and valuables out of the wet zone, then book 24/7 detection. Slow damp that is spreading still needs prompt attention. Structural damage and mould do not wait for a convenient weekday.

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London housing stock

Built for how London actually leaks

Housing stock across the capital fails in different ways. We match the method to the building, not a one-size survey script.

Victorian & Edwardian terraces

Original floorboards, cast-iron stacks and decades of patch repairs. We pressure-test circuits and listen through timber before any board is lifted.

Mansion blocks & conversions

Shared risers, stacked bathrooms and flat-to-flat disputes. Origin reports settle liability between leaseholders, freeholders and block insurers.

Post-war & 1970s stock

Copper branches, cold-water tanks and ageing joints. Acoustic and thermal methods locate slow drips that never show as a flood.

New-build flats & towers

Plastic pipe, underfloor heating and boosted mains. Tracer gas and thermal imaging matter more than a listening stick alone.

Questions

Leak Detection FAQs for London homeowners

How quickly can you get to me?

We aim to dispatch an engineer as soon as you call, 24 hours a day. Response times depend on London traffic, but we prioritise all calls as emergencies from the moment you contact us.

Do you cause a lot of damage finding the leak?

No. Our primary methods are non-invasive. We use sensitive listening devices and thermal imaging to locate leaks through walls and floors, avoiding unnecessary damage to your property.

What should I do while I wait for your engineer?

If safe to do so, turn off your internal stop tap to stop the water flow. Move valuables and furniture away from damp areas. Do not attempt to open up walls or ceilings, as this can complicate the detection process.

Can you find leaks in underfloor heating or complex systems?

Yes. Our equipment is designed for complex systems common in London properties, including underfloor heating, pressurised systems in modern apartments, and the old pipework found in period homes.

What happens after you find the leak?

We provide you with a clear location and a technical report. You can then use this report with your chosen plumber or builder to make the repair, knowing exactly where the problem is.

Is leak detection covered by home insurance in London?

Often yes, through trace and access cover on buildings policies when escape of water has caused damage. Limits and exclusions vary. Notify your insurer before instructing works if required, and use a firm that produces cause, origin, method and moisture evidence. We write reports for that purpose.

How much does leak detection cost in London?

Checkatrade publishes UK leak detection at £80 to £1,600 per job, with an average of £162, most jobs between £115 and £234, and the upper end reserved for hard-to-trace work. Published hourly diagnostic rates run £95 to £145, which is where open-ended bills come from. Those are third-party market figures rather than a quote for your property. What matters more is the structure: our detection fee is fixed and agreed before the visit, so it cannot drift while the search runs, and any repair is quoted separately once the leak has been located.

Is leak detection covered by home insurance?

Usually, through trace and access cover in your buildings policy, though the limit varies widely and some basic policies carry none at all, so check your own schedule for the figure. It can reimburse the detection survey plus the cost of opening up and reinstating floors or walls. Two conditions matter: the escape of water must have caused damage (trace and access is not a standalone claim), and the leak cannot stem from gradual wear or poor maintenance. A detailed report stating cause, origin, method and moisture readings is what loss adjusters expect.

How long does a leak detection survey take?

A typical London domestic survey takes two to four hours. Straightforward cases - a single circuit failing a pressure test with a clear acoustic signal - can be pinpointed faster. Complex jobs, such as leaks under screeded floors, underfloor heating loops or long external supply pipes, can take a full day because circuits must be drained and tracer gas given time to surface. You should have the leak located to a repairable point in one visit.

Can a water leak be found without ripping up floors?

Yes. Non-invasive methods locate the vast majority of hidden leaks before anything is opened up: acoustic microphones and correlators listen for escaping water, thermal imaging maps temperature anomalies from hot pipes, tracer gas (hydrogen in nitrogen) rises through concrete and tiles to a detector, and moisture mapping tracks the spread. Floors are only lifted once the leak is pinpointed, which keeps access damage - and reinstatement costs - to a single small area.

Who is responsible for a water leak - me or Thames Water?

It depends where the pipe sits. The water company owns the communication pipe up to your property boundary. From the boundary to your home, the supply pipe is your responsibility - although Thames Water often repairs or subsidises a first leak on an external supply pipe free of charge, so contact them before paying for work. Everything inside the property is yours; in flats, communal pipework is normally the freeholder's responsibility under the block policy.

Why does my boiler keep losing pressure if no leak can be found?

The most common culprit is a failed expansion vessel or internal boiler fault, which drops system pressure without any water escaping into the building - so detection equipment finds nothing because there is nothing to find. Forum discussions document homeowners paying multiple detection firms before this was checked. Before booking a survey, have the boiler's expansion vessel tested and, during any survey, insist each heating circuit is pressure tested separately to isolate the true source.

Explore the cluster

Related leak detection services & guides

Acoustic detection

Listen for pressurised pipe noise

Thermal imaging

Map wet and warm anomalies

Tracer gas

Find plastic-pipe and screed leaks

Underground leaks

Supply pipe and mains traces

Trace & access

Insurer-ready reports

Pricing

Fixed fees and no find no fee

Areas we cover

All 33 London boroughs

Leak detection guide

How methods compare

Insurance claims

Escape of water explained

London-wide

Leak Detection across all 33 boroughs

Same multi-method kit and fixed-fee approach from Barking to Richmond. Pick your borough for local housing detail.

Water going somewhere it shouldn't?

Tell us the symptoms and your postcode. We'll confirm the visit, the fixed detection fee and the arrival window before you commit to anything.

Book a detection visit