Leak detection in London
A damp patch that will not stay gone no matter how many times it is painted over. A stain slowly spreading across a ceiling. A water bill that has crept up for no reason anyone can point to. In all three cases the source has to be found before anything gets repaired, otherwise you are paying to fix a symptom rather than the actual leak.
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- DBS-checked engineers
- Emergency callout available 24/7
- Price agreed before work starts
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Monday – Sunday, 7:00 AM – 10:00 PM · Out-of-hours emergency? Call 020 3576 5825
Get a price for leak detection
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Thanks — we’ve got it
We’ll come back to you on the number you gave us. If it’s urgent and you’d rather not wait, call 020 3576 5825.
What this includes
- Hidden pipe leaks under floors and behind walls
- Damp and water-damage investigation
- Unexplained increases in water usage
- Leaks under solid and tiled floors
- Heating system pressure loss
- Pre-purchase and pre-refurbishment checks
Worth knowing first
A little of this might mean you do not need to call us at all — we would still rather you knew it.
The meter test
Turn off every tap and appliance, then read your water meter. Leave it an hour with nothing running and read it again. If it has moved, you have a leak somewhere on your supply. That one test tells us a great deal before we arrive.
Losing boiler pressure
A boiler that needs topping up every few weeks is usually leaking somewhere in the heating circuit, often a pinhole in pipework under a floor. It is worth finding, because it corrodes the system from the inside as it refills.
A damp patch is rarely above the leak
Before it ever shows itself, water tends to run some distance along a joist or under a floor. That means the stain on your ceiling can be well away from the actual failed pipe — which is exactly why the Ninja Plumbers approach is to locate the leak first, rather than start cutting holes on a hunch and hoping one of them is right.
Talk to your insurer first
Many home insurance policies cover trace and access, meaning the cost of finding the leak and making good afterwards. Worth a call before booking the work, and we can provide a report if they want one.
What affects the price
You are paying for the search, and the repair is priced separately once the leak is found. How long the search takes depends on the building, the pipework involved and how much the leak is giving away.
Which system is leaking
The heating circuit, the mains cold supply, the hot water and the waste pipes are each tested in a different way. Isolating and pressure-testing them one at a time narrows things down when the culprit is not obvious, but every extra system adds time.
What the floor is made of
Pipes under a suspended timber floor are relatively easy to listen to and reach. Pipes buried in a concrete screed, tangled up with underfloor heating or beneath large stone tiles make the signal harder to read and the search slower.
A steady leak or an occasional one
A leak that runs all the time shows up clearly when the pipework is pressure-tested. One that only appears when the shower is on, or when the heating is hot, has to be recreated during the visit before it can be traced.
Inside the house or under the garden
If the meter test shows a loss but nothing inside is wet, the leak may be on the supply pipe under the front garden or path. Tracing along a buried external pipe is a different search, and usually a longer one.
The price is agreed before any work starts. We take card and cash.
Common questions
Will you have to lift my floor?
Detection itself is non-invasive. Once the leak is located, the repair may need access at that one point, but that is a targeted opening rather than exploratory work across a room.
How accurate is it?
Acoustic and thermal equipment will normally narrow a leak down to a small area. Nothing is perfect through solid concrete, and we will tell you honestly if a site is difficult rather than overpromising.
My water bill has doubled. Is that a leak?
Often it is, especially if nothing about how you use water has actually changed. Run the meter test described above first, then tell us what it showed when you call — it saves time on the visit.
Can you give me a report for my insurer?
Yes. Tell us at the point of booking that you need one, so the engineer documents the job properly on the visit.
Should I turn the water or heating off before you arrive?
Only if the leak is actively causing damage. Otherwise leave things running normally, because a leak that is still behaving as it usually does is far easier to trace. If you have already turned the stopcock off or let the boiler pressure drop, that is fine — just tell us when you book, so the engineer knows to repressurise the system before starting the tests.
Can you repair the leak on the same visit?
Sometimes. If the leak turns out to be in reach — under a floorboard, behind a bath panel, at a valve — and the engineer has what is needed, the repair can often follow straight on, once you have agreed the price for it. If it is buried in a screed floor or behind tiling, the repair usually needs planning, materials and sometimes other trades, so it becomes a separate booking.
Leak Detection near you
Local pages for the areas where this comes up most.
Related appliance work
These installations sit under this service, and each has its own page covering what is involved.
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Water Meter Installation
The pipework side of going metered — including the shared supplies that stop it happening.
More on water meter installation
More plumbing work we take on
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Emergency Plumbing
Burst pipes, major leaks and no water. We take calls around the clock and get an engineer moving.
More on Emergency Plumbing -
General Plumbing
Taps, toilets, radiators and pipework. The jobs that never quite get done.
More on General Plumbing -
Leaking Ceiling
Water dripping or pouring through a ceiling. What to do first, then the source found and stopped — in your home or the flat above.
More on Leaking Ceiling -
Leak Repair
Leaks you can see — dripping joints, weeping valves, perished hoses, overflows running outside — isolated, repaired and checked properly afterwards.
More on Leak Repair -
Toilet Repair
Toilets that will not flush, keep running, fill slowly or leak onto the floor. Usually one worn part, replaced without needing a new toilet.
More on Toilet Repair -
Tap Repair and Replacement
Dripping, stiff and leaking taps repaired, and tired ones swapped for new.
More on Tap Repair and Replacement -
Pipe Repair
Burst, split, frozen and corroded pipework repaired — or replaced where patching it would be pointless.
More on Pipe Repair -
Low Water Pressure
Weak taps and showers diagnosed by testing, not by swapping parts and hoping.
More on Low Water Pressure -
Lead Pipe Replacement
Old lead supply pipes replaced with new, from the boundary into the house.
More on Lead Pipe Replacement -
Commercial Plumbing
Offices, restaurants, retail and blocks of flats, worked around your opening hours.
More on Commercial Plumbing -
Gas Safety Certificates
Landlord gas safety certificates issued by a Gas Safe registered engineer, with the paperwork sent the same day.
More on Gas Safety Certificates
Not sure whether it is a leak or damp? A slow leak often looks like damp, and the reverse. See damp survey & diagnosis, damp proofing & penetrating damp and condensation & ventilation control, or our damp and condensation page.
Need leak detection in London?
Describe the problem and give us your area, and we’ll tell you the price before anyone starts work.