How acoustic leak detection finds leaks in underground supply pipes

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 UK's leading leak detection specialists, who's here to answer your questions and provide expert leak detection advice. Today's question is one we hear a lot from homeowners: how does acoustic leak detection actually find a leak when the pipe is buried underground and you can't see a thing?

Dave

It's a great question because it sounds almost like magic when you first hear about it. The principle is straightforward though. When water escapes through a crack or a failed joint under pressure, it produces sound. That sound travels along the pipe wall and up through the ground, and acoustic listening equipment picks that up.

George

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

Dave

Exactly. ADI's engineers use ground microphones and listening rods to detect the vibration the escaping water creates. You place the sensor on the surface above the pipe route and work methodically along the line. The signal gets stronger as you move closer to the breach and weaker as you move away. That change in intensity is what tells you where to focus.

George

And how do you know where the pipe actually runs? Most homeowners haven't got a clue where their supply pipe goes once it leaves the street.

Dave

That's half the job, honestly. Before any acoustic work starts, ADI's engineers will trace the pipe route. We use the stop tap location, the meter position and sometimes a pipe locator to map the line under your garden or driveway. Once you know the route, you've got a corridor to work along, and then the acoustic survey can begin.

George

What does the equipment actually look like? I'm picturing something out of a science fiction film.

Dave

It's a lot less glamorous than that. A listening rod is essentially a metal probe you press against the ground or against a fitting. Ground microphones sit flat on the surface and pick up vibration through the soil. Both feed into a display unit that shows the signal level, and the engineer interprets what the readings mean. There's real skill in reading the output because you're filtering out background noise from traffic, other pipes, all sorts.

George

Does that background noise cause problems? Say the pipe runs under a busy road.

Dave

It can make things trickier. Harder surfaces like concrete and tarmac actually conduct sound better than soft ground, which helps. Loose or waterlogged soil can dampen the signal. Plastic pipes transmit less vibration than copper or steel, so the leak needs to be producing a reasonably strong signal for the acoustic method to give a confident result. Where the signal is weak, pressure testing alongside acoustic listening helps to confirm what we're seeing.

George

Can you explain how pressure testing fits in? Is that a separate process?

Dave

It's complementary. Pressure testing confirms there's a leak present and gives an idea of how significant it is. You isolate the pipe, pressurise it and watch whether pressure holds or drops. ADI's engineers use that alongside acoustic detection rather than as a replacement for it. The acoustic work is what actually locates the point of the breach.

George

Once you've identified the spot, how precise are we talking? Do you still end up digging up half the garden?

Dave

The whole point of the acoustic survey is to minimise that. When the process works well, our engineers can pinpoint a leak to within a very small area, so excavation is targeted and contained. You're looking at one dig rather than a trench the length of the garden. That's a significant difference for the homeowner in terms of disruption and reinstatement.

George

And is this something homeowners usually leave until the problem is obvious, like a patch of wet ground outside?

Dave

Too often, yes. A lot of people only call when they notice the lawn is soggy or their water bill has crept up with no explanation. A spinning meter when all the taps are off is one of the clearest signs, and it's worth acting on that early. An underground supply leak that's left running costs money month on month and can cause ground movement around foundations depending on the soil type.

George

That's a really useful way to think about it. Dave, thanks so much for walking us through this. For anyone with an unexplained wet patch or a water bill that won't behave, ADI Leak Detection brings the expertise and equipment to get to the bottom of it without guesswork. ADI are one of the most trusted and experienced teams in UK residential leak detection, so they're well worth your first call.

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.