How to detect an underground water leak
A hidden leak on your side of the water meter runs day and night and shows up on every bill until it is fixed. Here are the signs to look for, a meter test you can do yourself in an hour, and how a licensed plumber pinpoints the leak without digging up the whole yard.
Book leak detection — call 0403 156 503Six signs of a hidden underground leak
Your water bill jumped with no change in usage
An unexplained increase of even 20 to 30 percent usually means water is escaping somewhere between the meter and your taps. Underground leaks run 24 hours a day, so the bill is often the very first clue.
The water meter moves when everything is off
Turn off every tap and appliance, then watch the meter's smallest dial. If it keeps creeping, water is still flowing somewhere on your property.
Damp or unusually green patches in the yard
A soggy spot, spongy lawn or a strip of grass that is greener than the rest during a dry Brisbane spell often sits directly over a leaking service line.
Hissing, whistling or trickling in the walls
Pressurised pipes make a faint hiss when they leak. It is loudest at night when the house is quiet, and often near the meter or a wall cavity.
Dropping water pressure
Showers and taps that have gradually lost pressure can mean water is being lost before it reaches the fixture, especially in older galvanised or poly service lines.
Cracks, movement or musty smells
Water tracking under a slab softens the soil beneath it. New cracks in paths, tiles or brickwork, and a persistent musty smell inside, can point to a slab leak.
The water meter test, step by step
This is the single most reliable check a homeowner can run before calling anyone. It takes about an hour and costs nothing.
- 1Turn off every tap inside and outside, and stop the washing machine, dishwasher, irrigation system and ice maker.
- 2Find your water meter (usually near the front boundary) and write down the full reading, including the smallest dial.
- 3Leave the property's water completely untouched for 30 to 60 minutes.
- 4Read the meter again. If the numbers have moved at all, water is escaping somewhere on your side of the meter.
- 5If the meter has moved, shut the main off at the meter to limit damage and book a licensed plumber for leak detection.
How we pinpoint the leak
Knowing you have a leak is easy. Knowing exactly where it is, under a slab, driveway or garden bed, is what saves you money. We use non-destructive detection first, so any excavation is targeted.
- Acoustic leak detection. Ground microphones and electronic amplifiers pick up the specific sound frequency water makes as it escapes a pressurised pipe, letting us pinpoint a leak through soil, concrete and paving.
- Thermal imaging. An infrared camera shows the temperature difference created by escaping water behind walls, under floors and beneath slabs, without opening anything up.
- Pressure and isolation testing. We isolate sections of your plumbing and pressure test each one to narrow the leak down to a single run of pipe before any excavation.
- Tracer gas and pipe locating. For difficult buried lines we introduce a safe tracer gas and use electronic pipe locators to map depth and route, so digging is precise and minimal.
- CCTV drain cameras. For sewer and stormwater lines, a camera shows cracks, root intrusion and collapses, and marks the exact depth and position from the surface.
When it is an emergency
Water bubbling to the surface, a sudden loss of pressure, or water pooling against the house needs immediate attention. Turn the main off at the meter and call us on 0403 156 503. We run 24/7 emergency leak repairs across Brisbane and the Gold Coast.
Frequently asked questions
How do I detect a water leak underground?
Start with the meter test: turn off every tap and water-using appliance, then check whether the smallest dial on your water meter is still moving. If it is, look for damp or unusually green patches in the yard, listen for hissing near the meter and walls, and note any drop in water pressure. If the meter moves with everything off, call a licensed plumber for acoustic or thermal leak detection before digging.
How do I test my water meter for a leak?
Turn off all taps, the washing machine, dishwasher and any irrigation. Write down the meter reading, including the fine dial, and wait 30 to 60 minutes without using water. If the reading has changed, water is escaping somewhere on your property.
How much does leak detection cost in Brisbane?
Professional leak detection in Brisbane typically runs from about $250 to $600 depending on the size of the property and the equipment required, with the repair quoted separately once the leak is located. Tago Plumbing provides an upfront written price before any work starts.
Can an underground water leak damage my home?
Yes. Water escaping under a slab or path erodes the soil supporting it, which can cause cracking, movement and mould. It also wastes thousands of litres and shows up on every quarterly bill until it is repaired, so it is worth acting quickly.
Who is responsible for an underground leak, me or the water authority?
In Queensland, the water authority is responsible for the pipework up to and including the meter. Everything on the house side of the meter, including the service line running across your yard, is the property owner's responsibility.
Do you offer emergency leak detection?
Yes. Tago Plumbing runs 24/7 emergency plumbing across Brisbane and the Gold Coast. If you have a burst or fast-running leak, shut off the main at the meter and call 0403 156 503.
Think you have a hidden leak?
We locate underground leaks across Brisbane and the Gold Coast with upfront pricing before any work starts. Licensed QBCC 15575089.
Call 0403 156 503Want costs first? See our Brisbane plumbing price guide.