The equipment we use to find leaks.
Every engineer carries the full kit, because no single method finds every leak. Here is what each one does, what it is good at, and where it falls short.
Why we bring every method to every job.
A thermal camera cannot see a cold-water leak under a thick slab. A ground microphone struggles in a busy store with the chillers running. Tracer gas needs a pipe that can be isolated and drained. Each method has a blind spot, and the blind spots are different.
Used together, one confirms what another suggests. The position we mark is the one the evidence agrees on, which is why the shop floor stays whole until the repair goes in at the right spot.
- Thermal imaging cameras
- Acoustic listening & ground mics
- Tracer gas detection
- Leak correlators
- Borescope cameras
- Moisture meters
- CCTV drain cameras
- Pressure testing
- Drone roof inspection
What each method does.
Plain descriptions, including the limits. The method that finds your leak depends on the pipe, the floor and the building.
Thermal imaging cameras
Show the temperature difference a hot-water or heating leak leaves in tiles, plaster and screed.
A thermal camera shows surface temperature as colour. Hot water and heating pipes warm the floor or wall above them, and a leak spreads that warmth into a shape that does not match the pipe run. A cold-water leak can show too, as an area cooler than its surroundings because evaporation is taking heat out of the material.
It is fast and covers a large area, which makes it the first sweep on most jobs. Its limit is depth: a thick concrete slab or a layer of insulation can hide the pattern, and it shows where the heat is, which is not always exactly where the water is leaving the pipe. That is why it is paired with acoustic listening or tracer gas before anything is marked.
Typical retail useHeating and hot-water pipes under a tiled shop floor, and ceiling leaks from the unit above.
Acoustic listening & ground mics
Hear pressurised water escaping beneath concrete, tarmac and block paving.
Water escaping from a pressurised pipe makes a noise, and that noise travels along the pipe and through the ground around it. Ground microphones and listening sticks pick it up at the surface, and the engineer follows the sound to where it is loudest.
It works on cold mains as well as hot, and through tarmac, block paving and concrete. Background noise is its enemy: chillers, air handling and traffic all get in the way, which is one reason a quiet store early in the morning gives a cleaner result.
Typical retail useWater mains under a car park or service yard, and supply pipes under a slab floor.
Tracer gas detection
A safe hydrogen and nitrogen mix put through the pipe escapes at the break and is picked up at the surface.
The pipe is drained and filled with a safe, non-flammable mix of hydrogen and nitrogen. Hydrogen is a very small molecule, so it escapes at the break and travels up through concrete, screed and tile to the surface, where a hand-held detector picks it up.
It is the most direct method for a leak that thermal and acoustic cannot resolve, and it works on heating circuits, hot and cold plumbing and buried mains. The pipe has to be isolated and drained first, so we plan it for a period when that system can be off.
Typical retail useA heating circuit losing pressure under a solid floor, with no visible wet patch anywhere.
Leak correlators
Two sensors on a water main calculate the position of the leak between them.
Two sensors are placed on the pipe either side of the suspected leak, on valves, hydrants or fittings. The leak noise reaches each sensor at a slightly different time, and the correlator uses that difference, with the pipe length and material, to calculate where between the two points the leak is.
It is built for long buried mains where walking the whole run with a microphone would take too long. It needs access to the pipe at two points and a pipe that carries sound well, so it is less use on short plastic runs inside a building.
Typical retail useThe mains feed across a retail park, or along a service road to a supermarket.
Borescope cameras
See inside voids, ducts and behind fitted units through a hole the size of a coin.
A borescope is a camera on a flexible cable, small enough to go through a hole the size of a coin. It lets the engineer look inside a boxed-in pipe run, behind a fitted unit, under a raised floor or into a ceiling void without opening it up.
It confirms what the other methods suggest by showing the wet pipe or the dripping joint. It only sees what the cable can reach, so it is used to check a suspect spot rather than to search a whole unit.
Typical retail useChecking the pipework behind a till run or inside a boxed-in duct before any joinery is removed.
Moisture meters
Map how far the water has travelled and separate a leak from condensation.
Moisture meters measure how wet a material is, either through pins pushed into the surface or through a sensor that reads a short way into it. Taking readings in a grid across a wall or floor maps the extent of the water and shows the direction it is travelling.
The map matters because water rarely surfaces where it leaks. It also separates a leak from condensation or rising damp, which look similar on the surface and need a very different fix.
Typical retail useA stock room wall shared with another unit, where the question is whose leak it is.
CCTV drain cameras
Survey drains, gullies and interceptors from the inside.
A camera on a rod or a small crawler is fed along the drain, sending video back to a screen. The engineer sees cracks, displaced joints, root ingress and blockages, and can measure how far along the run they are.
Drains are not pressurised, so acoustic methods do not apply, and a leaking drain often shows as a smell or a soft patch rather than a wet one. The camera is the direct way to see the fault, and the recording goes into your report.
Typical retail useA service yard drain under a delivery bay, or a foul drain beneath a food unit.
Pressure testing
Confirm which circuit is losing water before anyone starts looking for it.
Before searching, the engineer isolates the suspect system and puts a gauge on it. A heating circuit or a section of pipe that holds its pressure is not leaking. One that drops is, and the rate of the drop gives a sense of how big the leak is.
It is the step that stops time being spent in the wrong place. In a unit with mains, hot water, heating and possibly a sprinkler feed, testing each in turn narrows the search to one system before any camera comes out.
Typical retail useSeparating a mains leak from a heating leak in a shop where the boiler needs topping up and the water bill has also risen.
Drone roof inspection
Survey large flat roofs and rooflights without scaffolding or a cherry picker.
A drone with a camera surveys a roof from above, covering a large flat roof, its outlets, rooflights and upstands in minutes. With a thermal camera fitted it can show where water is being held in the roof build-up after rain.
It replaces scaffolding or a cherry picker for the first look, which keeps the car park open and the cost down. Flying depends on weather and airspace rules, and any defect it finds is then checked by hand.
Typical retail useA leaking flat roof over a large-format store or a retail park unit.
Method by leak type.
A tick means the method is regularly part of the search for that kind of leak. Most jobs use three or four.
| Method | Water mains | Heating | Roof & ceiling | Under-floor | Drains | Damp & structural |
|---|---|---|---|---|---|---|
| Thermal imaging cameras | Used | Used | Used | Used | Not used | Used |
| Acoustic listening & ground mics | Used | Used | Not used | Used | Not used | Not used |
| Tracer gas detection | Used | Used | Not used | Used | Not used | Not used |
| Leak correlators | Used | Not used | Not used | Not used | Not used | Not used |
| Borescope cameras | Not used | Used | Used | Used | Not used | Used |
| Moisture meters | Not used | Not used | Used | Used | Not used | Used |
| CCTV drain cameras | Not used | Not used | Not used | Not used | Used | Not used |
| Pressure testing | Used | Used | Not used | Used | Used | Not used |
| Drone roof inspection | Not used | Not used | Used | Not used | Not used | Not used |
How the evidence adds up.
Three stages on every job. Nothing is marked on the floor until the third one is done.
Isolate
Pressure and meter tests decide which system is leaking, so the search starts in the right place.
Locate
Thermal, acoustic, tracer gas and correlators each point to an area. Where they overlap is where we look closer.
Confirm
A borescope, moisture readings or a small check at the marked spot proves it before anyone opens up the floor.
Equipment questions.
The things managers ask when they see the kit come out of the van.
Is tracer gas safe in a food store?
Yes. The gas is a non-flammable mix that is mostly nitrogen with a small proportion of hydrogen. It is vented after the test, and the system is refilled and put back into service.
Can a thermal camera see through a concrete floor?
Not through it, but it sees the effect. A warm pipe heats the slab above it and the camera shows that pattern on the surface. A cold-water leak under a thick slab may not show, which is when acoustic listening or tracer gas takes over.
Will the equipment disturb customers?
Very little. Most of it is hand-held and quiet, and nothing is dug up, so customers can usually shop around us.
Do you use the same equipment on every job?
Every engineer carries the full kit, and which methods are used depends on the system and the building. The report says which methods were used and what each one showed.
How accurate is the final position?
Accurate enough for the repair to be made through a small opening at the marked spot rather than a trench or a lifted floor. We do not quote a figure in centimetres, because it depends on pipe depth, material and surface. We mark the position and explain how confident the evidence is.
Speak to the team about your leak.
Call with what you have noticed and we will send an engineer with everything needed to find it, without lifting the floor to look.
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