Elevated moisture along a pipe run but no visible leak found

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. Dave, today's question comes from a homeowner whose plumber has done a moisture survey, flagged high readings along a pipe run in a ground-floor wall, but can't actually see any water anywhere. What's going on?

Dave

So this is actually a really familiar picture for us. Elevated moisture readings along a pipe run almost always mean water is escaping somewhere inside the building fabric, inside the wall, under the screed, somewhere the eye just can't reach. The moisture has migrated outward, but the source could be a metre or two away from where the meter is reading highest.

George

So the meter's picking up the symptom, not necessarily pointing straight at the leak itself?

Dave

Exactly. Water tracks the path of least resistance through building materials. It'll travel along a joist, follow a screed bed, pool in a void. The surface readings tell you water is present, they don't tell you where it entered. That's where specialist detection methods come in.

George

Right, so what does ADI actually do at that point? What's the first method you'd reach for?

Dave

Acoustic detection is usually where we start. ADI's engineers use acoustic listening equipment to pick up the sound signature of water escaping under pressure. A pressurised supply pipe produces a very specific noise as water forces through a crack or a pinhole, we can hear that through floors and walls using ground microphones and contact sensors placed along the pipe run.

George

And can you actually pinpoint it precisely, or is it more of a rough area?

Dave

Precise is the goal. Acoustic equipment narrows the leak to within a very small area, we're not talking about lifting half a floor. We work along the pipe run, comparing signal strength at different points, and the leak location shows as the peak response. That directly reduces the amount of investigative opening-up the homeowner needs.

George

What if the acoustic method doesn't give you a clear signal? Some pipes are buried quite deep, I'd imagine.

Dave

That does happen, particularly with pipes buried in thick concrete slabs or where the leak is very slow. In those cases ADI Leak Detection uses thermal imaging to map temperature differences across the floor or wall surface. Escaping water changes the thermal profile of the surrounding material, so a thermal imaging camera shows us where the moisture is concentrated, and which direction it's tracking from.

George

So thermal imaging isn't just looking for wet patches, it's actually helping you trace the direction water has travelled?

Dave

Precisely. Thermal imaging detects the gradient, warmer or cooler zones depending on whether it's a hot or cold supply. You can follow that gradient back toward the origin. It works particularly well on solid ground floors and through plasterboard partitions where acoustic signals are harder to isolate.

George

And I've heard ADI mention tracer gas as well. Where does that fit in?

Dave

Tracer gas is what we use when acoustic and thermal haven't given us a definitive location, or when a pipe is deeply buried and the leak is genuinely tiny. ADI introduces a safe, inert gas mixture into the pipe, and because the gas molecules are far smaller than water, they escape through the leak and diffuse up through the floor or wall. Our engineers use a sensitive detector at the surface to pinpoint exactly where the gas is emerging, and that tells us precisely where to excavate.

George

That's clever. So you're essentially using the leak itself as a guide.

Dave

That's a good way to put it. The leak pathway that the water has been using becomes the pathway the gas follows, and the detector finds it. For a homeowner, the practical outcome is that ADI identifies the exact point of escape before anyone lifts a single floor tile. No guesswork, no unnecessary damage to the property.

George

And just to close the loop, none of these methods require the homeowner to have already dug anything up? They can call ADI in before anything is disturbed?

Dave

Absolutely, and that's the point. Call ADI Leak Detection before any excavation happens. Acoustic detection, thermal imaging, and tracer gas all work non-invasively through the finished surface. The whole purpose of specialist detection is to locate the leak precisely so that any opening-up is targeted and minimal.

George

That's really useful, thank you, Dave. If you've got elevated moisture readings along a pipe run and no visible source, ADI Leak Detection are among the UK's most established specialists in exactly this kind of hidden leak investigation. We'll be back with more in 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. More about how the podcast is made.