Can Thermal Imaging Find a Water Leak?

Yes, thermal imaging can find many water leaks, but it does not see the water itself. A thermal camera measures the surface temperature of walls, floors and ceilings. Leaking water changes that temperature, either warming the surface around a hot water pipe or cooling it as cold water soaks into plaster, timber or concrete and evaporates. The camera turns those differences into a colour image that points to where the water is coming from.

It is fast and completely non-invasive, but it has real limits, and a thermal image on its own is not a diagnosis.

What a thermal camera actually sees

A thermal camera cannot see through walls. It reads infrared energy given off by the surface in front of it. What it shows is a temperature pattern, and the technician’s job is to work out what is causing that pattern. A leak usually produces a distinctive shape, such as a warm line along a pipe route, or a cool patch that spreads out and down from a single point, which is different from the patterns made by sunlight, insulation gaps or air conditioning.

Leaks thermal imaging finds well

Hot water leaks in slabs and walls

This is where thermal imaging is strongest. A leaking hot water pipe warms the surrounding concrete or wall, and the camera shows a warm bloom centred on the fault. In older Perth homes with copper hot water lines run through the slab, this is often the first sign of a leak, alongside a floor that feels warm underfoot.

Shower and wet area leaks

Water escaping behind tiles or under a shower base soaks into the surrounding material and cools it as it evaporates. On camera this shows as a cool patch, usually spreading from the source, and it can be visible well before the paint bubbles or the skirting swells.

Leaks from upper floors and roof spaces

Leaks from an upstairs bathroom or a hot water unit in the roof space often show on the ceiling below as a cool or warm stain long before it becomes visible damage.

Tracing pipe routes

Running hot water through a line makes the pipe visible on camera as a warm path across the floor or wall. This shows where the pipe actually runs, which speeds up acoustic leak detection and avoids searching in the wrong place.

Where thermal imaging has limits

Thermal imaging struggles with cold water leaks deep underground, because by the time the water reaches the surface its temperature has evened out with the soil. It is also unreliable outdoors in direct sun, and on reflective surfaces such as glossy tiles, glass and stainless steel, which can bounce heat from elsewhere back to the camera.

Perth’s summer adds its own challenge. Walls and slabs that have baked all afternoon hold heat well into the evening, which can hide a leak or create patterns that look like one. During the warmer months, inspections are often more reliable early in the morning, before the building heats up.

Why a thermal image alone is not proof

A temperature anomaly is a lead, not a confirmed leak. Before a location is reported, it should be checked with another method, such as a moisture meter, acoustic listening on the pipework, or a pressure test on the line. This matters because an incorrect reading leads to tiles, plaster or concrete being opened in the wrong place.

The same applies to the low cost thermal attachments now available for phones. They can show that something is different about an area, but they cannot tell you why, and they are easy to misread.

Common questions

Can a thermal camera see through walls?

No. It reads surface temperature only. Leaks are found by interpreting the temperature pattern the water creates on the surface.

Can thermal imaging find a leak under a concrete slab?

Hot water slab leaks often show clearly. Cold water leaks under a slab are less reliable and usually need acoustic detection or tracer gas.

Is thermal imaging safe?

Yes. The camera is passive. It only receives infrared energy and gives off nothing, so it is safe for people, pets and the building.

Spotted a warm floor or a damp patch?

If you have a floor that feels warm, a stain that keeps returning or a water bill that does not add up, contact Subtronic Leak Detection. We locate hidden water leaks across Perth, Mandurah, Rockingham and regional Western Australia, then report the exact position so your plumber can repair it in one visit.