Hidden water leaks are one of the most damaging and costly plumbing problems a homeowner can face. Unlike a visible dripping tap or a burst pipe that floods your floor, hidden leaks occur inside walls, under floors, beneath concrete slabs, and in underground supply lines where they can go undetected for weeks, months, or even years. During that time, they cause progressive damage to your home’s structure, encourage mould growth, attract termites, and steadily drive up your water bills.
The average Australian household loses thousands of litres of water each year to undetected leaks. In Rockingham, where water costs continue to rise and the sandy soil conditions can mask underground leaks, detecting hidden leaks early is essential for protecting both your home and your wallet.
Here are the five most common signs that you have a hidden water leak in your home and what to do about each one.
1. An Unexplained Increase in Your Water Bill
The most reliable early indicator of a hidden water leak is a sudden or gradual increase in your water bill that does not correspond to a change in your water usage habits. Water Corporation bills for Rockingham homes are issued periodically, and comparing your current usage to the same period in previous years is the most effective way to spot an anomaly.
A small leak, such as a hairline crack in a pipe inside a wall cavity, may only waste a few litres per hour. Over a billing period, however, this adds up to thousands of litres and a noticeable increase in your bill. A larger leak in an underground supply line can waste tens of thousands of litres and result in a dramatic bill increase.
If your water bill has increased and you have not installed a new irrigation system, filled a swimming pool, had house guests, or changed your usage patterns, a hidden leak is a likely explanation. The first step is to check your water meter for leaks using the simple meter test method. If the meter confirms water is flowing when all taps and appliances are off, you have a leak somewhere in your system.
Keep in mind that seasonal variations in water use are normal. Compare usage to the same season in previous years rather than to the immediately preceding period.
2. Damp Patches, Stains, or Discolouration on Walls and Ceilings
Water stains on walls, ceilings, or floors that appear without an obvious external cause are a strong indicator of a hidden leak within the structure of your home. These stains typically present as yellowish or brownish discolouration on painted surfaces, expanding damp patches that may feel cool or soft to the touch, bubbling or peeling paint or wallpaper, and warping or swelling of skirting boards, door frames, or other timber elements.
The location of the stain can help narrow down the source of the leak. A stain on the ceiling directly below a bathroom may indicate a leaking shower recess, bath waste, or toilet seal. A damp patch on a wall that shares plumbing with a kitchen or laundry may indicate a leaking pipe within the wall cavity. Stains that appear at floor level along an external wall may indicate a leaking underground supply pipe or rising damp caused by a broken drain.
It is important to note that damp patches do not always appear directly below the leak source. Water can travel along pipes, beams, and other structural elements before it finds a point where it soaks into a visible surface. This means the leak may be some distance from where the stain appears, which is why professional leak detection using specialised equipment is often necessary to pinpoint the exact location.
Do not ignore damp patches or assume they will dry out on their own. Even a small persistent leak creates conditions that promote mould growth within wall cavities, which can cause respiratory health problems and require expensive remediation.
3. The Sound of Running Water When No Taps Are Open
If you can hear the sound of water running, dripping, or hissing when all taps, appliances, and irrigation systems in your home are turned off, water is escaping somewhere in your plumbing system. This is one of the more definitive signs of a hidden leak because it provides direct audible evidence of water movement.
The sound may be faint and only noticeable in quiet conditions, such as late at night when ambient noise levels are low. It may come from inside walls, under floors, or from beneath your home’s slab foundation. Try placing your ear against walls in the kitchen, bathroom, and laundry areas to listen for the sound of running water within the wall cavity.
A hissing sound may indicate water escaping under pressure from a pinhole leak in a copper pipe or a failed joint. A more pronounced running or flowing sound may indicate a larger leak or a broken pipe. A dripping sound may indicate water leaking from a concealed fitting and dripping into a wall cavity or under a floor.
If you can hear running water but cannot locate the source, contact a licensed plumber who can use acoustic leak detection equipment to trace the sound to its origin. Modern leak detection technology can pinpoint leaks within walls and under slabs without the need for destructive investigation in most cases.
4. Mould or Mildew Growth in Unexpected Places
Mould and mildew require moisture to grow, and their presence in areas that are not normally damp is a strong indicator of a hidden water leak providing a continuous source of moisture. While it is normal to see some mould in bathrooms and wet areas where humidity levels are high, mould growth on bedroom walls, in wardrobes, on living room ceilings, or in other dry areas of the home is not normal and warrants investigation.
Hidden leaks inside wall cavities create a damp, dark environment that is ideal for mould growth. The mould may be visible on the surface of the wall or ceiling, or it may be hidden behind the wall lining where it cannot be seen but can often be smelled. A persistent musty or earthy smell in a room, particularly one that is stronger when doors and windows have been closed, often indicates hidden mould growth.
In Rockingham’s warm climate, mould can establish and spread quickly once a moisture source is available. Even a small leak that keeps a wall cavity damp can lead to extensive mould colonisation within a few weeks. The health implications of mould exposure include allergic reactions, respiratory irritation, and exacerbation of asthma symptoms, particularly in children, the elderly, and people with compromised immune systems.
If you notice mould in unexpected locations, do not simply clean it off and assume the problem is solved. The mould will return as long as the moisture source remains. Have the area investigated by a plumber to identify and repair the underlying leak before arranging mould remediation.
5. Unusually Wet or Green Patches in Your Garden
If a section of your garden or lawn is consistently wetter, greener, or more lush than the surrounding area without any irrigation to explain it, an underground water leak may be providing a constant water supply to that spot. This is particularly noticeable in Rockingham’s sandy soils during the dry summer months when most lawns are stressed and dry.
Underground supply lines that connect the water meter to your home run beneath your front garden or driveway. Sewer and stormwater drains run beneath and around your property. A crack or break in any of these pipes can release water into the surrounding soil, creating a localised wet area.
Other signs of underground leaks include soil that is soft, boggy, or subsiding in a specific area, a persistent puddle or damp patch that does not dry out after rain has stopped, paths or driveways that are sinking or cracking due to soil washout beneath them, and increased insect activity including mosquitoes breeding in the standing water and termites attracted to the moisture.
Underground leaks in the supply line between your meter and your home are your responsibility as the homeowner. Water Corporation is responsible for the supply line from the main to your meter, but the section on your property is yours to maintain and repair.
What to Do If You Suspect a Hidden Leak
If you have observed one or more of these warning signs, take the following steps. First, perform the water meter test to confirm whether water is flowing when all taps and appliances are off. Second, check for any visible leaks under sinks, behind toilets, at hot water system connections, and at washing machine and dishwasher hoses. Third, if the meter test confirms a leak but you cannot find a visible source, contact a professional leak detection service.
Professional leak detection uses a combination of acoustic listening devices, thermal imaging cameras, and moisture meters to locate leaks within walls, under floors, and underground without the need for destructive investigation. Once the leak is located, targeted repairs can be made with minimal disruption to your home.
Do Not Delay Leak Repairs
The longer a hidden leak goes undetected and unrepaired, the more damage it causes and the more expensive the repair becomes. Water damage to timber framing, plasterboard, flooring, and electrical wiring can turn a simple pipe repair into a major renovation project. Early detection and prompt repair saves money, prevents structural damage, and protects the health of your household.
Plumber Rockingham provides professional leak detection and repair services across Rockingham, Baldivis, Port Kennedy, Secret Harbour, Warnbro, and all surrounding suburbs. If you suspect a hidden water leak in your home, contact us to arrange an inspection. We use the latest detection equipment to find leaks quickly and accurately, minimising disruption and getting the problem fixed before it escalates.
