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Plumbers find leaks with a toolkit built to avoid tearing your house apart: acoustic listening gear that hears water escaping under pressure, thermal imaging that sees the temperature signature of wet or warm areas behind surfaces, pressure testing that proves which pipe section is losing, tracer gas for the truly stubborn cases, and calibrated detectors with manometer testing for gas lines. In Melbourne, professional leak detection typically costs $250 to $600 depending on the property and how elusive the leak proves, and it routinely pays for itself by replacing exploratory demolition with one precise repair.
And yes, a plumber can do leak detection, gas included: gas leak investigation is licensed gasfitting work, which in Victoria is a class of plumbing.
First, prove you actually have a water leak
Before any equipment comes out, there’s a test you can run tonight for free. Turn off every tap and water-using appliance, read the water meter, wait an hour without using water, and read it again. If the numbers moved, water is leaving the system somewhere. Our guide to detecting a water leak walks through this and the other homeowner checks: a water bill that’s jumped without explanation, damp patches, mould, a hot water system that never seems to rest, the sound of water with everything off. A warm patch on a concrete floor is its own tell, usually a hot water line leaking under the slab.
What the DIY checks can’t do is locate the thing, and location is the whole game. The difference between “somewhere under the slab” and “1.2 metres from the laundry wall” is the difference between jackhammering a floor on spec and cutting one neat access hole.
How professional water leak detection works
Acoustic detection. Water escaping a pressurised pipe makes noise. Ground microphones and listening rods pick it up through slabs and walls, and an experienced ear triangulates the loudest point down to a small patch of floor. The equipment is impressive; the operator’s ear is the real instrument.
Thermal imaging. A thermal camera reads temperature differences through surfaces: the cold track of saturated plaster, or the warm plume of a leaking hot water line. It’s the quickest way to map how far moisture has travelled, and to separate a plumbing leak from a shower seal failure or a roof entry before anyone opens anything.
Pressure testing. Isolating sections of pipework and watching test pressures tells us definitively which line is losing and roughly how badly, which matters when a property offers several suspects.
Tracer gas. For the leak nothing else will surrender, a safe hydrogen-nitrogen mix goes into the pipe, escapes at the fault, and gets picked up at the surface by a sensitive detector.
Together, these methods find leaks under slabs, inside walls, in ceilings and along buried external lines. It’s the daily kit of our water leak detection team, and the industrial-strength version runs through our commercial leak detection work, where an undetected leak on a commercial meter turns into serious money remarkably fast.
How gas leaks are found
Gas announces itself by smell, thanks to the odourant added to natural gas and LPG, but smell doesn’t locate, and small leaks sit below the nose’s threshold entirely. A licensed gasfitter traces concentrations to their source with an electronic detector, makes small escapes visible with soapy solution on fittings, and proves the system tight with a manometer pressure test: gas isolated, line pressurised, and any pressure drop over the test period confirms a leak, section by section, until it’s found.
If you can smell gas right now: meter valve off, no switches or flames, windows open, and call. Our gas leak detection team treats every suspected leak as urgent, because that’s what it is.
What it costs and what happens next
As a Melbourne guide: water leak detection typically runs $250 to $600, gas investigation similar, with complex multi-line or commercial properties above that. What you get isn’t a hunch but a located fault and a fixed quote for the repair, whether that’s a pipe section, a re-route, or a slab leak fixed through one precise opening. The unglamorous truth of leak work is that finding the fault is the hard part; once it’s found, the fix is usually routine. One of our reviews captures the satisfying end of that process, describing our plumber Cam’s repair of the failed taps behind a persistent leak as “completed to a high standard,” and the customer “very happy with the repairs.” Finding it first is how repairs get to be that boring.
Frequently asked questions
How do plumbers detect leaks? Acoustic listening equipment, thermal imaging, section-by-section pressure testing and tracer gas for water; electronic detectors, soapy solution and manometer testing for gas.
Can a plumber detect a gas leak? Yes. Gas leak investigation is licensed gasfitting work, done with calibrated instruments rather than guesswork.
Can a plumber do leak detection? Yes, and the specialist equipment is precisely what separates locating a leak from demolishing your way toward one.
How much does it cost to have a water leak detected? Typically $250 to $600 in Melbourne. Against exploratory demolition, detection is usually the cheapest step in the entire repair.
Meter creeping while every tap is off? Call O’Shea Plumbing on 03 8566 8450 or book leak detection. We find it first, fix it second, and the price is fixed before either.
