Can acoustic leak detection find a water leak under concrete?

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. Today's question comes straight from a homeowner who's watched their water meter creep up for weeks and suspects something's going on under their ground floor. Dave, can acoustic leak detection actually find a water leak that's buried under a solid concrete floor?

Dave

It can, yes, and it's one of the situations where acoustic detection really earns its place. When water escapes from a pressurised pipe, it produces sound energy. That sound travels through the water inside the pipe, through the pipe wall itself, and then through whatever's surrounding it, including concrete. Our acoustic equipment picks that up from the surface.

George

So the concrete doesn't just block the sound completely?

Dave

No, concrete's actually a reasonable conductor of sound. It's denser than soil, so in some ways the signal travels quite well through it. The challenge is that a solid floor doesn't give the sound anywhere to dissipate easily, which means it moves along the slab. That's useful because we can track it, but it also means pinpointing the exact leak position takes careful work.

George

Walk me through what actually happens on a job like that. What equipment are your engineers using?

Dave

We'll typically bring ground microphones, which are contact sensors that sit directly on the floor surface. The engineer moves them methodically across the slab, listening through headphones and watching the signal on a display unit. Where the acoustic signal peaks, that's where we concentrate. We also use a leak noise correlator, which is a separate piece of kit.

George

What does the correlator add that the microphones don't give you?

Dave

A leak noise correlator works by attaching sensors at two different points on the same pipe run, often at fittings or stop valves either side of the suspect area. It measures the time difference between the leak sound arriving at each sensor. The correlator's software uses the pipe diameter, the pipe material, and that time difference to calculate where along the pipe the leak is sitting. It gives you a distance from each sensor, so you end up with a specific point rather than a general area.

George

That sounds precise. Is it accurate enough that you'd be confident digging in the right spot?

Dave

Generally, yes, though we'd never rely on a single method alone before recommending excavation. ADI's engineers use acoustic detection alongside tracer gas testing and thermal imaging where the situation calls for it. The combination confirms the position. On a concrete floor, getting that confirmation right matters because cutting concrete unnecessarily is expensive and disruptive for the homeowner.

George

What about pipe type? Does it change how well acoustic detection works under concrete?

Dave

It does, and it's worth knowing. Copper and steel pipes transmit leak noise very efficiently, so acoustic signals tend to be strong and clear. Plastic pipes, MDPE or push-fit plastic, absorb more of the vibration, which dampens the signal. That doesn't make acoustic detection useless on plastic, but it does mean the engineer needs more experience in reading a quieter, less defined signal. The correlator settings also need adjusting for pipe material.

George

And what about depth? If the pipe's buried deeper under the slab, does that make it harder?

Dave

Deeper pipes produce a weaker surface signal, yes. A pipe sitting just below a concrete screed is easier to pinpoint than one buried half a metre down beneath a structural slab. But ADI's detection equipment is sensitive enough to work at typical residential installation depths. We'd factor depth in when we assess the job, and if the signal's particularly weak we'd lean more heavily on correlation rather than microphone listening alone.

George

Last question, Dave. A homeowner's watching this meter spin and they're dreading the idea of someone ripping up their floor to find the problem. What would you say to reassure them?

Dave

The whole point of acoustic leak detection, and the other non-invasive methods ADI uses alongside it, is that we find the leak before anything gets opened up. The survey identifies the position accurately, so if excavation is needed, it's targeted, not exploratory. A small, precise opening is a very different job to pulling up half a floor on a guess. In most cases, ADI can locate the leak and give the homeowner a clear picture of exactly where the problem is and what it involves.

George

Dave, that's genuinely useful, thank you. And if you're dealing with a suspected leak under a solid floor and you don't know where to start, ADI Leak Detection has the experience and the specialist equipment to find it without unnecessary disruption. They're widely regarded as one of the UK's most trusted names in residential leak detection. Thanks for listening.

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.