Most hidden leaks aren't dramatic. They're a toilet that seeps quietly into the pan, an irrigation solenoid that never quite shuts, or a pinhole in a buried copper line under the front lawn. The first sign is almost always the bill.
The meter test: do this before you call anyone
- Turn off every tap, appliance, irrigation controller and ice maker in the house
- Go to the water meter at the front boundary and note the reading, including the small red dial
- Don't use any water for two hours — overnight is even better
- Read the meter again. Any movement means water is escaping somewhere on your side of the meter
If the small leak indicator dial is spinning while nothing is running, you have an active leak right now. Photograph both readings — it's useful evidence for us and for any water authority concession application.
Narrowing it down yourself
Close the main isolation valve at the house (not the meter). Watch the meter again. If it stops, the leak is inside the house or under the slab. If it keeps moving, the leak is between the meter and the house — the buried service line, an outside tap, or the irrigation system.
The usual suspects, ranked by how often we find them
- Toilet cisterns — a failed outlet washer can waste more water than a family of four uses
- Flexible hoses under vanities and sinks weeping at the crimp
- Irrigation solenoid valves stuck partly open, especially after a dry spell
- Hot water tempering valves and pressure relief valves discharging continuously
- Underground copper or poly service lines with corrosion pinholes
- Slab leaks in hot water lines — warm patches on the floor, hot water pressure that fades
Signs your leak is under the slab
Unexplained warm spots on tiles, a hot water system that cycles when nobody's using hot water, damp skirting boards, a musty smell in a room with no visible source, or new cracking in a slab-on-ground floor. These need acoustic and thermal detection rather than guesswork — cutting concrete on a hunch is expensive.
How we locate leaks without demolition
We start with pressure testing to confirm which line is losing water, then use acoustic listening gear to hear the escape point through slab or soil, thermal imaging to trace hot water lines, and tracer gas where a line is very deep or noisy. On drains and sewer lines we run a CCTV camera and locate the fault to a marked point on the surface. The goal is one small, precise opening — not an exploratory trench.
What it costs you to ignore it
Beyond the bill, a persistent leak under a slab softens the ground supporting your footings, feeds mould behind wall linings, and can be excluded from an insurance claim if it can be shown the damage happened gradually. Insurers pay for sudden escapes of water far more readily than long-term seepage.
Preventing the next one
- Replace flexible hoses every 5–8 years — they are the number one cause of indoor floods
- Check the toilet by dropping food colouring in the cistern; colour in the pan means a leaking outlet valve
- Have the pressure limiting valve checked — high mains pressure shortens the life of every fitting in the house
- Run the meter test each quarter when your bill arrives
Frequently asked questions
- How do I know if I have a hidden water leak?
- Turn off all water use, read your meter, wait two hours without using water, then read it again. Any change means water is escaping on your side of the meter.
- Can a leaking toilet really raise my water bill that much?
- Yes. A continuously seeping cistern outlet valve can lose thousands of litres a quarter while making almost no noise and leaving no visible drip.
- Who is responsible for a leak between the meter and my house?
- In NSW, the property owner is responsible for all pipework on the house side of the water meter. The water authority maintains the main and the meter itself.
- Do you have to dig up the yard or break the slab to find a leak?
- Usually not. Acoustic leak detection, thermal imaging and tracer gas let us pinpoint the leak first, so any excavation is a single small opening at the fault.
- Can I get a water bill concession for a hidden leak?
- Many NSW water authorities offer a leak allowance if you repair a concealed leak promptly and supply a plumber's report. Keep your meter photos and repair documentation.
- Which suburbs do you cover for leak detection?
- All of Shellharbour, Shell Cove, Flinders, Warilla, Albion Park, Oak Flats, Dapto, Kiama and the wider Wollongong area.