What actually happens on a leak detection survey
No mystique and no jargon. Here is the whole process, the equipment we use at each stage, and what you are left holding at the end of it.
- 01
Before we arrive
We ask what you are seeing, when it started, what has already been tried, and whether the water meter moves with everything turned off. Half the diagnosis often happens on that call, and it is free.
- Where the stop tap is, so we can isolate quickly if we need to
- Whether the boiler is losing pressure, and how fast
- Whether the damp changes with the weather — that points at the building, not the plumbing
- 02
Trace
A full non-invasive survey of the affected area. We rule systems out as deliberately as we rule them in, because a documented elimination is evidence in its own right.
- Thermal imaging across floors, walls and ceilings
- Acoustic listening and correlation along pressurised runs
- Moisture mapping to establish the extent and the direction of travel
- Pressure testing circuit by circuit to isolate the failing one
- 03
Access
One opening, in the right place, as small as the job allows. In most cases that is a borescope hole the size of a pencil, and a larger opening only if the repair itself needs the room.
- The location marked and photographed before anything is cut
- Borescope confirmation first wherever it is possible
- Dust sheets down, and the debris taken away with us
- 04
Repair
The fault fixed on the same visit wherever it can be, and guaranteed for 12 months. Anything larger is priced as a fixed quote before a spanner is lifted.
- Pipework cut back to sound material and properly jointed
- Fixed-price quote for excavation, screed or roof work
- Access made good to a sound and safe standard
- 05
Prove
This is the stage most people never get. The repair is tested under pressure and watched, the moisture readings are taken again, and the whole job is documented.
- Pressure held and timed, with the result recorded
- Post-repair moisture readings across the affected area
- Dated photographs, methodology and a clear causation finding
- A cost schedule for access and reinstatement, for your insurer
The equipment
What each instrument is genuinely good at
Nobody finds every leak with one tool. Matching the method to the fault is most of the skill, and it is why we arrive with all of them rather than the cheapest one.
Thermal imaging camera survey
Water moving where it should not changes the temperature of everything it touches. A thermal camera renders those differences as an image, so a leak under a solid floor shows up as a shape long before it shows up as a stain. It is completely passive: nothing is drilled, lifted or cut to take the reading.
Best for
- Underfloor heating leaks
- Leaks under screed and tiled floors
- Tracing pipe runs before any floor is lifted
- Mapping the true extent of water damage behind a wall
Acoustic leak correlation
A pressurised leak makes a continuous noise that travels along the pipe wall. Sensors placed either side of a suspected run measure the tiny difference in arrival time between them, and the correlator converts that into a distance. On a mains supply pipe this routinely gets us to within a foot of the fault.
Best for
- Underground mains water supply leaks
- Leaks under driveways, patios and lawns
- Buried pipework in commercial premises
- Pinpointing a fault before any excavation
Tracer gas testing
Hydrogen is the smallest molecule there is, so it finds its way out of a crack far too small to see and rises straight up through concrete, screed and soil. We sweep the surface with a sensitive detector and the reading spikes directly over the breach. The gas mix is non-toxic, non-flammable at the concentration used, and leaves nothing behind.
Best for
- Very small or intermittent leaks
- Leaks with no pressure behind them
- Central heating and underfloor circuits
- Confirming a find made by another method
Moisture mapping and salts analysis
Damp on its own does not tell you where water came from. Rising ground moisture leaves nitrate and chloride salts behind; a burst pipe does not. Testing the salt content of a plaster sample separates a plumbing leak from rising damp or condensation, which is often the difference between a valid insurance claim and a rejected one.
Best for
- Distinguishing a leak from rising damp or condensation
- Mapping how far water has travelled
- Evidence for a trace and access claim
- Checking a repair has actually dried out
Pressure and flow testing
We cap a section of pipework, raise it to a controlled test pressure and watch the gauge. A circuit that holds is eliminated; a circuit that drops is quantified. Repeating this system by system narrows a whole-house problem down to a single run, and gives a hard number for the report rather than an opinion.
Best for
- Identifying which system is leaking
- Central heating pressure loss
- Proving a repair before reinstating
- Quantifying loss rate for insurers
CCTV drainage survey
Where waste water is escaping rather than supply water, the fault is usually a cracked, displaced or root-invaded drain. The camera carries a sonde so we can mark the position of the defect on the surface above, and the footage doubles as evidence for an insurer or a neighbour dispute.
Best for
- Foul smells and recurring blockages
- Subsidence investigations
- Waste water under floors
- Pre-purchase drainage checks
Borescope inspection
When every non-invasive method points at the same spot, a borescope gives visual confirmation before anything is properly opened up. The access hole is small enough to fill and touch in with a dab of filler, which is why we always try it before lifting a floor or cutting a ceiling.
Best for
- Confirming a find inside a wall or ceiling void
- Inspecting under suspended timber floors
- Checking behind bath panels and shower trays
- Keeping any access hole as small as possible
Tracer dye testing
Ideal where several possible sources share the same wet patch. A shower tray, a waste trap and a heating pipe can all end up on the same ceiling; dosing them one at a time and watching where the dye emerges answers the question definitively rather than by elimination.
Best for
- Shower tray and wet room leaks
- Leaks between flats and maisonettes
- Swimming pool and hot tub leaks
- Roof and gutter ingress paths
Pipe and cable tracing
Knowing where a pipe actually runs, as opposed to where the drawings say it runs, prevents the two most expensive mistakes on any leak job: digging in the wrong place, and putting a spade through a live service. We mark the route on the surface and record the depth.
Best for
- Locating a buried supply pipe
- Planning an excavation safely
- Finding capped or abandoned runs
- Underfloor heating loop mapping
Roof integrity and voltage testing
A single pinhole in a felt, EPDM or GRP roof can flood a ceiling while the roof looks perfect from above. Electronic testing energises the membrane and locates the exact point where current, and therefore water, is getting through, so the repair is a patch rather than a re-roof.
Best for
- Flat roof leaks
- Balcony and terrace waterproofing
- Warm roof and green roof build-ups
- Commercial single-ply membranes
Think you have a leak? Let us find it.
Non-invasive survey, same-day response and a written report your insurer will accept. No call-out fee, and no charge for advice over the phone.