Leak detection in London
Finding the leak without taking the house apart. Trace and access work for insurers, and pressure loss you cannot explain.
Service overview
A hidden leak is a different job to a burst pipe. Nothing is spraying, but a ceiling is staining, a floor is damp, or the boiler pressure keeps dropping and nobody can say why.
The mistake is opening up the most likely spot and hoping. Water travels along joists and under screed, so where it appears is often nowhere near where it is escaping. We locate the leak first and open up once.
Most of this work falls into two groups: heating systems losing pressure, and mains or waste leaks showing up as damp. They are traced differently.
We work across Greater London and north Surrey, including Croydon, Bromley, Sutton, Orpington and Wimbledon. Gas Safe engineers do every gas job. See the gallery, about us or get in touch.
Get a quoteSigns you need leak detection
- Boiler pressure drops every few days with no visible leak
- A damp patch or stain that keeps returning
- Water meter moving with every tap in the property closed
- Warm patch on a floor over heating pipework
- Musty smell in a room with no obvious source
- An insurer has asked for trace and access before authorising repair
Trace and access, and why insurers ask for it
Trace and access is the industry term for finding a leak and getting to it, and most home insurance policies cover it as a distinct item. The policy typically pays to locate the leak and to make good the damage caused by getting to it, even where the failed pipe itself is excluded.
That is why insurers want a proper trace rather than exploratory holes. A documented, located leak supports a claim; a floor lifted in three places on a hunch does not. If you are claiming, tell us at the point of booking and we will make sure the report matches what your insurer needs to see.
Pressure loss on a heating system
A sealed system that keeps dropping below about 1.0 bar is either leaking or has an expansion vessel that has lost its charge. Those are completely different jobs, so the vessel gets tested first — there is no sense hunting for a leak that does not exist.
If it is a genuine leak, the usual suspects are buried pipework under floors, a weeping radiator valve, the pressure relief valve discharging outside, or a pinhole in a run within a screed. The pressure relief pipe is worth checking yourself: if there is water at the outside end, the system is losing pressure through the valve rather than through a hidden pipe.
Mains, waste and where the water actually goes
Water follows the path of least resistance, which means it runs along joists, down the outside of a pipe, or sideways under a floor before it appears. A stain on a kitchen ceiling can easily come from a bathroom two rooms away.
One check anyone can do: turn every tap and appliance off and look at the water meter. If it is still creeping round, water is leaving the system somewhere between the meter and the property. That single test separates a supply-side leak from a waste or heating leak and saves a great deal of time.
How the visit goes
Rule out the simple things
Expansion vessel, pressure relief discharge and meter test before anything more involved.
Trace it
Non-invasive tracing to narrow the leak to a location rather than a room.
Access once
One opening in the right place instead of three in the wrong ones.
Repair and document
Pipe repaired, and the report written so it stands up to an insurance claim.
Standards this work is held to
Trace and access cover
Most home insurance policies cover the cost of locating a leak and accessing it as a separate item, often even where the pipe repair itself is excluded. Check your policy wording before paying out of pocket.
Sealed system pressure
A domestic sealed heating system should sit at roughly 1.0 to 1.5 bar cold. Persistent loss below that means a leak or a failed expansion vessel.
Water Supply (Water Fittings) Regulations 1999
Governs how supply pipework and fittings must be installed and protected, including backflow prevention.
What a small leak actually costs
A weep losing 1 litre an hour is over 8,000 litres a year. On a metered supply that is money, and under a floor it is damage long before anyone sees water.
Expansion vessel charge
A domestic expansion vessel is normally pre-charged to about 1 bar. When that charge is lost the system pressure swings high when hot and low when cold, which looks exactly like a leak on the gauge.
Where buried pipe runs
Supply and heating pipe buried in screed is usually 15mm, and in newer flats it is often laid in continuous runs with no joints under the floor. That makes a pinhole in the pipe wall the likely failure rather than a fitting, and it is why locating it to within a few centimetres matters before any screed is broken.
Leak detection: common questions
Related to Leak detection
Areas we cover
We work across Greater London and north Surrey, including Croydon, Bromley, Sutton, Orpington and Wimbledon. Pick your town.
Need an emergency plumber?
Burst pipes, boiler breakdowns and blocked drains across Greater London. We aim to be with you within 60 minutes.