Water Leak Detection in Older Melbourne Homes: Why Acoustic Technology Finds What Plumbers Miss

Updated May 2026 — Around The Clock Plumbing Pty Ltd, Oakleigh South.

Water leak detection in older Melbourne homes is the process of locating a hidden leak — behind a wall, under a concrete slab, or beneath the ground — without digging up the house to find it. In older homes especially, acoustic technology is what makes this possible: a sensitive listening device picks up the distinctive sound a pressurised pipe makes as water escapes, letting a plumber pinpoint the leak to within about half a metre before lifting a single tile. Here is why older homes leak in ways newer ones don't, how acoustic detection works, and when it's worth calling for.

Why acoustic water leak detection finds what plumbers miss in older homes

A plumber without the right equipment has to guess where a hidden leak is, and chasing it often means cutting exploratory holes or lifting flooring until the source turns up. Acoustic water leak detection removes that guesswork. It listens for the specific sound of water escaping a pressurised pipe and traces it back to the exact spot before anything is opened up. In older homes, where pipes are more likely to be corroded, jointed and buried under decades of renovation, that precision is the difference between one neat repair and a wall full of holes.

Why do older Melbourne homes develop hidden leaks?

Older homes often run on ageing galvanised steel or early copper pipework that corrodes from the inside out, along with original joints that loosen over time. Melbourne's reactive clay soils make it worse: they swell and shrink with the seasons, shifting the ground and putting stress on buried pipes and slab plumbing. Add tree roots seeking moisture and decades of additions and renovations, and a slow leak can run for months behind a wall or under a slab before anyone notices.

How does acoustic leak detection actually work?

When water escapes a pressurised pipe through a crack, pinhole or failed joint, it makes a distinctive sound that carries through the pipe, the surrounding soil and even a concrete slab. A sensitive ground microphone and acoustic detector pick up that sound, and by comparing how strong it is at different points, the plumber traces it back to the precise location.

Around The Clock Plumbing uses a Sewerin A200 acoustic leak detector, which can pinpoint a leak to within roughly 0.3 to 0.5 metres and works at depths of up to 5 to 6 metres. That accuracy means a hidden leak gets the same treatment as any other job: fast arrival, accurate diagnosis with the right equipment, and a permanent fix to the one section of pipe that's failed, rather than to the whole floor.

What are the signs you might have a hidden water leak?

A hidden leak rarely announces itself. The common signs include:

• A water bill that jumps with no change in how much water you're using.

• A damp, warm or discoloured patch on a floor, wall or ceiling.

• A musty smell, or mould appearing somewhere that shouldn't be wet.

• The sound of running water when every tap is turned off.

• A drop in water pressure you can't otherwise explain.

• An area of floor that feels warm underfoot, which can signal a hot water line leaking under the slab.

• The water meter still ticking over when everything in the house is switched off.

There's a fuller rundown in our guide to the five signs you need leak detection.

What can acoustic detection find that other methods can't?

Acoustic detection is built for pressurised water leaks — the supply lines running under slabs, behind walls and underground. That's a different job from a CCTV drain camera, which inspects the inside of drains and sewers on the waste side. For a concealed water leak, acoustic pinpointing, sometimes combined with thermal imaging and correlation, finds what a camera can't see and what guesswork misses. ATC carries the full range, which you can read about in advanced leak detection technologies, and there's more on concealed hot water leaks in our guide to slab leaks and concealed hot water leaks.

A real example: pinpointing a leak at a commercial site in Oakleigh

In September 2025, Around The Clock Plumbing was called to a commercial site in Oakleigh with a hidden water leak. Using the Sewerin A200, ATC located the leak acoustically and pinpointed it precisely, so the repair could target the exact section of pipe instead of excavating across the site on guesswork. That's the practical payoff of acoustic detection: less digging, less disruption, and a fix aimed squarely at the actual problem.

Common questions about water leak detection in older homes

How accurate is acoustic leak detection?

With the right equipment, a leak can be pinpointed to within about half a metre. ATC's Sewerin A200 locates leaks to roughly 0.3 to 0.5 metres and works at depths of up to 5 to 6 metres, which usually means one targeted repair rather than exploratory digging.

Can you find a leak under a concrete slab without digging?

Yes. Acoustic ground microphones can hear the sound of water escaping a pressurised pipe through a concrete slab, which lets a plumber pinpoint the leak before lifting any flooring.

What causes hidden leaks in older Melbourne homes?

The usual causes are corroded galvanised or older copper pipes, joints that have loosened over decades, and ground movement in Melbourne's reactive clay soils, which stresses buried and slab pipework.

Is acoustic leak detection the same as a CCTV drain camera?

No. Acoustic detection finds leaks in pressurised water pipes, while a CCTV camera inspects the inside of drains and sewers. They solve different problems and are often used alongside each other.

How do I know if I have a hidden leak?

Watch for an unexplained jump in your water bill, damp or warm patches, a musty smell, the sound of running water with the taps off, or the water meter moving when everything is switched off.

If you suspect a hidden leak, Around The Clock Plumbing's water leak detection service uses acoustic equipment to find it with minimal disruption, and you can review the team's licences and accreditations before you book.

Written and reviewed by Christopher Unwin, founder of Around The Clock Plumbing Pty Ltd, Oakleigh South. BPC Licence #50694, Type A gas, 22 years' experience. National Council member, Master Plumbers Association.