How acoustic detection finds where a mains water leak actually is

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 is one that causes a lot of anxiety for homeowners: if you've got a mains water leak, how do you actually know whether it's your problem to fix or the water company's?

Dave

It's a really common worry, that one. The short answer is that acoustic leak detection lets us pinpoint exactly where along the pipe the leak is sitting, and once you know the precise location, working out which side of the boundary it falls on is straightforward.

George

So walk me through it. What does acoustic detection actually involve when you're looking at a suspected mains leak?

Dave

Escaping water under pressure creates a sound as it forces its way out of the pipe. Acoustic equipment picks that sound up through the ground or through fittings on the surface. We place sensors at multiple points along the pipe route and the equipment compares the time it takes for the leak sound to reach each sensor.

George

And from those time differences you can work out where the leak is?

Dave

Exactly. The correlator software calculates the leak position by working out which sensor the sound reaches first and by how much. Done well, acoustic correlation places the leak to within a few centimetres on a buried pipe. That precision is what makes the liability question answerable.

George

Right, because if you don't know where it is, you can't say whose side of the boundary it's on. How does that boundary work? Where does the homeowner's responsibility start and the water company's end?

Dave

The legal boundary is the external stop tap, sometimes called the communication pipe stop tap, which is usually just inside the property boundary near the pavement. Pipework from the water main in the street up to that stop tap is the water company's responsibility. From the stop tap onwards into the house is the homeowner's private supply pipe.

George

So acoustic detection tells you which side of that stop tap the leak noise is coming from?

Dave

Precisely. ADI's engineers place acoustic sensors on the stop tap itself, on any accessible fittings between the stop tap and the house, and on fittings inside the property. The correlator then triangulates the leak source. If acoustic correlation places the leak between the water main and the external stop tap, that's the water company's pipe. If it falls between the stop tap and the internal stopcock, that's the homeowner's private supply.

George

Does the type of ground or the pipe material affect how reliable the readings are?

Dave

It does, yes. Plastic pipe absorbs sound more than copper or iron, so the acoustic signal travels a shorter distance and the sensor spacing needs adjusting. Clay or compacted soil transmits sound differently to loose fill or gravel. ADI engineers account for pipe material and ground conditions when they set the correlator's sound velocity parameters, because an incorrect velocity figure shifts the calculated leak position.

George

That's a detail I wouldn't have thought of. So once ADI has located the leak acoustically, what does a homeowner actually do with that information?

Dave

ADI provides a written report with the confirmed leak location, including a mark on the ground directly above the leak point. If acoustic survey results place the leak on the public supply network, the homeowner takes that report to their water company and the water company carries out the repair. If the leak is on the private supply pipe, the homeowner arranges repair and ADI's survey report means whoever does the excavation knows exactly where to dig rather than opening up a wide trench on a guess.

George

Which presumably saves a lot of unnecessary digging and disruption.

Dave

Considerably. Without acoustic location you're either excavating a long run of pipe hoping to find the fault, or relying on a wet patch at the surface, which often doesn't sit directly above the leak because water travels along the pipe bedding before it breaks through. Acoustic correlation removes that guesswork entirely.

George

Dave, that's genuinely clarified something that I think confuses a lot of people when they first notice a problem. Thanks for breaking it down so clearly. If you're dealing with a suspected mains leak and need to know whether it's yours to sort or the water company's, ADI Leak Detection has the acoustic survey expertise to give you a definitive, documented answer before a single spade goes in the ground.

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.