Acoustic detection vs thermal imaging for hidden water leaks

Full transcript

George and Dave in conversation. Every word of the episode, exactly as recorded.

George

Welcome to the ADI Leak Detection podcast. I'm here with Dave from ADI Leak Detection, the country's leading name in leak detection, who's here to answer your questions and provide expert leak detection advice. Dave, today's question comes up a lot from homeowners who've had a surveyor mention both acoustic detection and thermal imaging, and they genuinely don't know which one does what. So let's clear that up. What is acoustic leak detection actually doing?

Dave

Right, so acoustic leak detection works by listening. When water escapes a pressurised pipe, even a tiny pinhole, it produces a sound frequency as it forces through the gap. Our engineers place acoustic sensors on the floor surface or directly on the pipe, and the equipment picks up that sound and maps where it's loudest. That's where the leak is.

George

So it's literally listening for the water escaping?

Dave

Exactly. And the clever part is acoustic correlators, that's the more advanced version of the kit. You place two sensors at different points along a pipe run, and the correlator calculates the time delay between the sound reaching each sensor. From that delay and the known pipe length, it pinpoints the leak location to within a few centimetres, even under a solid concrete floor.

George

That's precise. So where does thermal imaging fit in? Is it doing something completely different?

Dave

It's a different principle entirely. Thermal imaging cameras detect heat differences, infrared radiation, basically. When water leaks into a wall or floor void, it changes the temperature of that material compared to the dry material around it. The camera shows that contrast as a colour variation on screen. So ADI engineers use thermal imaging to trace the moisture path escaping water leaves behind, rather than the sound it makes.

George

So thermal imaging is showing you where the water has travelled, not necessarily where it came from?

Dave

That's a really important distinction, yes. Water follows gravity and finds the path of least resistance, so it can travel quite a distance from the actual breach point before it shows up on a thermal image. Acoustic detection pinpoints the source directly because sound radiates outward from the leak itself. Thermal imaging maps the spread. You often need both pieces of information to get the full picture.

George

Does the type of pipe affect which method you'd go to first?

Dave

It does, quite significantly. Acoustic equipment performs best on metal pipework, copper and steel carry sound really well, so the leak signal travels clearly along the pipe to the sensors. Plastic pipes, which are everywhere in newer builds, dampen that sound. The signal degrades faster, so acoustic correlation is less precise on plastic. Thermal imaging doesn't care what the pipe is made of, it's reading the material around the leak, not the pipe itself.

George

And what about floor type? Does that matter for acoustic work?

Dave

Solid concrete floors actually transmit the acoustic signal well, which is why correlation works so effectively under screed or slab construction. Suspended timber floors are trickier, the air void under the boards breaks up the sound path. In those situations, ADI's engineers will often combine acoustic listening with thermal imaging of the floor surface to cross-reference findings before any floor's lifted.

George

Are there cases where neither acoustic nor thermal imaging gives you a clear enough answer?

Dave

It does happen, especially with very slow leaks where the pressure loss is minimal and the temperature difference is too small to show clearly on camera. That's where tracer gas comes in. ADI's engineers introduce a safe, inert gas into the pipe, and a detector traces it as it escapes through the leak point. Tracer gas locates leaks under solid floors and behind finished walls where both acoustic and thermal methods have limitations.

George

So the skill is knowing which tool fits the situation, not just owning the equipment?

Dave

That's it exactly. Acoustic correlation, thermal imaging, and tracer gas each give you a different type of evidence about a hidden leak. An ADI engineer reads the property first, the construction type, the pipe material, the leak behaviour, and selects the approach that'll give a definitive result without unnecessary disruption to the home. The goal is always to find the leak with the least possible damage to the fabric of the building.

George

Dave, that's genuinely made both methods much clearer. Thanks for breaking it down so plainly. If you've got a hidden water leak you can't locate, ADI Leak Detection is one of the UK's most established specialist teams in residential leak detection, well worth a visit to their website to find out how they work.

How this episode was made. This episode was produced using AI-generated voices and script, based on real leak detection questions and the working knowledge of ADI Leak Detection engineers. More about how the podcast is made.