A burst pipe is hard to miss. A slow leak inside a wall or under a slab is not. Hidden leaks can run for weeks or months, wasting water and damaging the property before anyone sees a drop. The good news is that they usually leave clues. This guide covers the warning signs to watch for, a simple meter test you can do at home, where hidden leaks tend to occur and how professional leak detection works.
Warning signs of a hidden leak
Water pipes run under slabs, inside walls and beneath paving, which is why finding hidden leaks in Perth often takes more than a quick look under the sink. The pipe may be out of sight, but the effects of a leak rarely stay hidden forever.
Watch for these signs:
- An unexplained rise in your water bill. If your habits have not changed and the bill has, a leak is a likely explanation.
- A water meter that keeps moving. If the meter moves when everything is off, water is going somewhere.
- Damp patches or stains on walls, ceilings or floors that do not dry out.
- A musty smell or visible mould, especially in a cupboard, a wall or a room that is otherwise dry.
- Peeling paint, bubbling plaster or swollen skirting boards. Moisture behind a surface often shows here first.
- Cracked or lifting tiles, floorboards or paving.
- The sound of running water when no taps are on.
- Soft, sunken or unusually green patches in the garden or along a path.
- Reduced water pressure that has no other obvious cause.
Any one of these can have another explanation. When two or three appear together, take them seriously.
The water meter test
The water meter is the easiest way to confirm whether you have a leak somewhere on the property. Water Corporation, the water provider for Perth, publishes steps for detecting a leak and a guide to reading your meter.
- Turn off all taps and every appliance that uses water. That includes the washing machine, dishwasher, irrigation and any automatic top ups.
- Find your water meter, which is usually near the front boundary, and note the reading. Many meters also have a small flow indicator, such as a dial or triangle, that spins when even a small amount of water passes through.
- Wait around 15 minutes without using any water.
- Check the meter again. If the reading has changed, or the indicator is still moving, water is flowing somewhere.
Before you assume the worst, rule out the common simple causes. A running toilet is one of the most frequent culprits, and it is easy to miss because water trickles quietly down the bowl. Check garden taps, hoses and irrigation as well. If the meter keeps moving after you have ruled those out, there may be a hidden leak in the pipework.
Where hidden leaks tend to hide
Leaks occur wherever pipes, fittings or appliances connect, and many of those spots are hard to see:
- Under the slab. Water pipes in many homes run beneath concrete. A leak there may only show up as a damp patch on the floor, a warm spot or an unexplained bill.
- Inside walls. Shower connections, taps and joints behind tiles or plasterboard can leak for a long time before the damage shows.
- Underground between the meter and the house. This section of pipe is exposed to soil movement, tree roots and age.
- Irrigation lines. A broken sprinkler pipe or a faulty valve can waste a surprising amount of water without any obvious sign on the surface.
- Pool and spa plumbing. Dropping pool levels that cannot be explained by evaporation can point to a leak.
- Hot water pipes. A leak on the hot side can show up as warm patches on the floor or a hot water system that never seems to keep up.
- Silent leaks from a worn cistern valve or seal are among the most common wasted water sources in a home.
How professional leak detection works
Finding a leak without tearing up the house is a skill. Different providers use different approaches, but the methods are broadly similar:
- Acoustic listening equipment. Sensitive microphones and ground sensors pick up the sound of water escaping from a pressurised pipe, which helps narrow down where to look.
- Thermal imaging. A thermal camera shows differences in temperature, which can help trace a hot water leak or find moisture within a surface.
- Moisture meters. These help confirm whether a wall or floor is wet and how far the moisture has spread.
- Pressure testing. Sections of pipe are isolated and tested to see whether they hold pressure, which shows which part of the system is leaking.
- Tracer gas. In some cases, a harmless gas is introduced into the pipework and detected where it escapes.
The goal is the same in every case: pinpoint the leak accurately so that any repair is targeted and any opening of walls or floors is kept to a minimum. If you are comparing providers, ask what methods they use and how they confirm the location before anything is cut or dug.
Why acting early matters
A leak that is found early is usually a smaller, cheaper job. Left alone, it can cause problems well beyond the cost of the water itself:
- Wasted water and higher bills. Even a small leak adds up over weeks and months.
- Damage to the building. Moisture can damage plaster, timber, flooring and cabinetry, and long term leaks near a slab can affect the soil around it.
- Mould and air quality problems. Damp conditions encourage mould, which can affect the health of people in the home.
- Insurance complications. Some policies may not cover damage from long running or gradual leaks, so it is worth reading yours and acting quickly if you suspect a problem.
It also helps to keep records. Note the dates of any unusual bills, meter readings and any visible damage. This gives a plumber a better starting point and can help if you need to discuss the matter with your water provider or insurer.
Follow the clues early
Hidden leaks are easy to ignore because they are out of sight, but the clues are usually there: a rising bill, a meter that will not stand still, a stain or a smell that does not go away. Do the meter test, rule out the obvious causes and call a licensed plumber when the signs point to something concealed. Finding a leak early is usually cheaper, and less disruptive, than finding it after it has done its damage.