Can acoustic ground microphones find a buried pipe 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, leading leak detection specialists across the UK, who's here to answer your questions and provide expert leak detection advice. Today's question comes straight from a resident on a council estate who's watching their water meter spin and suspects a burst pipe under the concrete path outside. Dave, can acoustic ground microphones actually find that kind of leak?

Dave

Yes, they can, and it's one of the scenarios acoustic equipment handles well. An acoustic ground microphone picks up the sound that escaping water makes as it forces its way out of a breach in the pipe and moves through the surrounding soil. That sound travels up through the ground, and the microphone captures it at surface level.

George

So you're essentially listening for the leak rather than seeing it?

Dave

Exactly right. ADI's engineers move the microphone along the path above where the pipe runs, and the signal strengthens as they close in on the source. The point where it peaks is where the leak is. On a concrete path over a shallow supply pipe, you'd typically get a strong enough return to pinpoint the breach within a pretty tight area.

George

That sounds straightforward. Is there anything that makes it harder on a council estate specifically?

Dave

Background noise is the big one. Estates can be busy, and if you've got traffic, plant machinery nearby or even other residents' heating systems running, that creates competing noise the equipment has to cut through. Our engineers work early if they can, or use more sensitive listening rods pressed directly against the surface to filter out ambient sound.

George

What about the pipe itself? Does the material make a difference?

Dave

It really does. Older metal pipes, particularly iron, carry leak sound along the pipe wall very efficiently, so the signal travels well. Plastic pipes, which are common on estate supply lines from the last few decades, absorb a lot of that sound energy. The leak noise still escapes into the ground, but it doesn't travel as far along the pipe, so you need to be more methodical about where you position the microphone.

George

And if the acoustic signal isn't strong enough to be certain?

Dave

That's when ADI's engineers bring in tracer gas. Tracer gas leak detection works by introducing a safe, inert hydrogen and nitrogen mixture into the pipe under low pressure. The gas is far lighter than air, so it escapes from the breach, rises through the soil and concrete, and a surface sensor detects it at ground level. Tracer gas locates leaks under solid floors and paths where acoustic signal alone is weak or ambiguous.

George

So the two methods work together rather than one replacing the other?

Dave

Precisely. On a job like this, acoustic listening gives you a strong initial indication of the zone, and tracer gas confirms the exact point. Using both means our engineers aren't guessing where to dig, which keeps disruption to the path and the surrounding area as small as possible.

George

That's got to matter a lot on a housing estate where you're working around people's front gardens and shared paths.

Dave

Hugely. Unnecessary excavation on a shared estate surface is a real problem, both for the residents and for whoever has to make the repair good afterwards. Accurate detection means you're cutting one small hole, not digging a trench hoping to stumble across the leak. That's the whole point of the survey before any spade goes in the ground.

George

One last thing, what tells the homeowner or the estate manager that there definitely is a leak under there, before you even start?

Dave

A spinning water meter with every tap and appliance turned off is the clearest sign. If the dial on the meter keeps moving, water is escaping somewhere on the supply between the meter and the property. Damp patches appearing through concrete or on nearby soil with no obvious surface source also point toward a buried pipe leak rather than anything above ground.

George

Dave, that's really useful. Thank you. If you're on a council estate or anywhere else and your meter is telling you something isn't right, ADI Leak Detection's engineers are among the most trusted in the country for tracing exactly this kind of hidden pipe leak non-invasively. We'll see you on the next episode.

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.