Leak detection methods: which instrument does what

There is no single instrument that finds every leak. There are methods, each of which sees something different, and the skill lies in choosing the right combination for the case in hand. Below is what each one does — no marketing, only physics.

Thermography (FLIR)

A thermal camera does not see through a wall. It reads the infrared radiation at the surface and the temperature differences across it. A wet zone behind plaster conducts heat differently from a dry one and appears on screen as a clear anomaly.

Strong at: underfloor heating, hot water, damp behind plasterboard, ceilings, terraces.
Weak at: cases with no temperature difference — which is why, where heating is suspected, we ask for the system to be switched on 2–3 hours before the inspection.

Moisture meters (Tramex)

A moisture meter measures the moisture content in the material itself, at depth rather than on the surface. This is the instrument that separates condensation from an active leak, and it produces the numbers that go into the report.

Strong at: concrete, screed, masonry, capillary damp from footings.
Weak at: establishing the exact run — it says “it is wet here, and by this much”, not “the pipe is fractured at this centimetre”.

The acoustic method (SebaKMT)

Water escaping under pressure through an opening in a pipe makes a noise. A geophone amplifies that noise and the operator traces it along the route. It is used mainly for underground runs and external mains.

Correlation

On long runs, walking the route step by step is impractical. A correlator places sensors at two points and calculates the position mathematically, from the difference in the time the noise takes to reach each sensor. This is the method for trunk water mains and long supply lines between buildings.

Technology for plastic pipes (Echologics)

Polyethylene muffles sound quickly and standard acoustics fail. Specialist systems work with the low frequencies characteristic of plastic pipelines, which is why they are used separately.

CCTV survey (Wöhler)

The camera physically enters the pipe and shows its internal condition: a crack, a fracture, displacement, roots, a foreign object, a reverse fall. Nothing here is assumed — you see the defect on screen.

Tracing pipes and cables

Before excavation it matters to know what runs below. Locators find metallic and non-metallic pipes, as well as cables live and de-energised, and establish their depth.

Why the combination matters

The thermal camera tells you something is wet. The moisture meter, how wet and at what depth. Acoustics, where along the route. The camera, what the defect is. Together they give a diagnosis; separately they give an opinion.

See the leak detection service or acoustic detection of external leaks.