How To Tell You’ve Got a Leak? Expert Leak Detection Tips

No one wants to deal with plumbing problems, least of all leaks! Yet so many of us end up living with that constant, nagging drip without even realising the damage it can cause. After all, how much damage can a small leak cause anyway?

A few small drops here and there might not seem like it’s cause for concern, but over time, it can quietly rack up your water bill and wreak havoc on your home. From damp walls and warped floors to mould growth and hidden water damage!

So, how can you tell if you’ve got a leak before it becomes a full-blown disaster? In this post, we’ll walk you through the key signs to watch for and what to do about it. By the end, you’ll be equipped to spot leaks early, save money, and protect your home from unnecessary damage.

Key Takeaways

• Even small water leaks can quietly cause structural damage, mould growth, and inflated utility bills if left unchecked.
• Common household leak sources include toilets, taps, showers, appliances, hot water systems, air conditioners, roofs, gutters, and plumbing pipes.
• Early warning signs of leaks include unexplained increases in water bills, water stains, damp or musty odours, mould growth, dripping sounds, and low water pressure.
• DIY leak detection methods, such as checking your water meter, inspecting visible pipes, monitoring appliances, and using food colouring for toilets, can help catch leaks early.
• Hidden leaks inside walls or underground often require advanced tools like moisture meters, acoustic sensors, thermal imaging, and tracer gases to locate.
• Hot water systems and evaporative air conditioners are often overlooked sources of leaks, with relief valves, blocked drainage, and corrosion being common culprits.
• Calling a professional leak detection specialist is recommended for hidden or complex leaks, as early intervention prevents costly repairs and protects your home’s value and safety.

Why Leaks Are a Serious Concern

A tap that drips here, a slight damp patch there, a leak isn’t that big of a deal…is it? Unfortunately, it can be far more serious than most homeowners realise.

1. Structural Damage

Water is surprisingly destructive over time. Constant moisture from leaks can weaken your home’s structure in several ways:

• Steel frames can rust and expand, compromising their integrity.
• Concrete can crack, crumble, or even fall away, leaving walls and foundations unstable.
• Masonry and arch bars may break or shift, while door frames can warp and misalign.
• Even small, hidden leaks can slowly cause major damage that isn’t immediately visible, leading to costly repairs down the line.

2. Mould Growth and Health Risks

Damp spots from leaks create the perfect environment for mold and mildew. Mould isn’t just unsightly, it’s a serious health concern, too:

• People with asthma or allergies may experience worsening symptoms.
• Those with weakened immune systems are at risk of lung infections.
• Prolonged exposure to certain molds can lead to rare but severe conditions like hypersensitivity pneumonitis.

3. Increased Utility Bills and Water Wastage

Leaks can silently drain both water and money:

• A single dripping tap can waste up to 30 liters per day, or roughly 2,700 liters every quarter.
• Faster drips or a leaky cistern can waste 316 liters daily. That’s about 28,000 liters every three months!
• Hot water leaks double the cost because you’re paying for both the water and the energy used to heat it.

💡Often, a spike in your water bill is the first warning sign that a leak is lurking somewhere in your home.

4. Long-Term Repair Costs vs. Early Detection Savings

Leaks may start small, but if left unchecked, the financial consequences can be substantial. Water that quietly seeps into walls, floors, ceilings, and other hidden areas can lead to serious structural damage over time.

Repairs might include fixing warped floors, replacing damaged plaster or drywall, restoring weakened foundations, or removing extensive mould infestations. Depending on the severity of the damage, these repairs can easily cost thousands of dollars.

Beyond immediate repair costs, ongoing moisture problems can also affect your property’s long-term value. Homes with a history of leaks or water damage may see a reduction in market value, sometimes as much as 10–25%!

The good news is that early detection is far more affordable and effective. Leak detection can pinpoint hidden leaks before they cause major damage, often at a fraction of the cost of repairs.

8 Common Sources of Leaks in Your Home

Leaks can happen anywhere, and over time, wear and tear from daily use makes them almost inevitable. Some leaks are obvious, but many hide in places you’d least expect. Knowing where to look is the first step to catching them early and avoiding costly damage.

1. Toilets and Cisterns: Toilets are one of the most common sources of household leaks. A worn-out flapper, cracked cistern, or faulty seal can allow water to leak constantly, sometimes silently. Even a slow trickle can waste hundreds of liters over a month.
2. Taps and Showerheads: Dripping taps and leaking showerheads are another common culprit that wastes water and energy, especially if they’re connected to a hot water system. Over time, worn washers, corroded fittings, or high water pressure can cause persistent drips.
3. Irrigation Systems and Garden Hoses: Outdoor water systems are often overlooked. Sprinklers, hoses, and garden taps can leak due to damaged fittings, cracks, or blockages.
4. Appliance Leaks: Dishwashers and Washing Machines: Modern appliances rely on multiple hoses and seals, all of which can fail over time. Dishwashers and washing machines can develop leaks around connections, door seals, or internal components, often causing water to pool underneath or behind the appliance.
5. Hot Water Systems and Relief Valves: Hot water systems are another common culprit. Corrosion, faulty valves, or pressure issues can cause leaks that are easy to miss, particularly if the water drips behind walls or under floors. Leaks from hot water systems are costly, as they waste both water and energy.
6. Evaporative Air Conditioners: Evaporative air conditioners can develop leaks from blocked drainage or corrosion. Water may drip into walls, ceilings, or onto floors, creating damp spots that can damage property over time.
7. Roofs and Gutters: Roofs and gutters are constantly exposed to the elements, which makes leaks inevitable. Damaged shingles, cracked flashing, or blocked gutters can let water seep into ceilings and walls, often causing structural damage if left unchecked.
8. Plumbing Pipes, Fittings, and Valves: Finally, your home’s plumbing network is full of potential leak points. Pipes can corrode, joints can loosen, and valves can fail. Hidden leaks behind walls or under floors are common and often go unnoticed until they cause significant water damage.

6 Signs That You’ve Got a Leak

Leaks often start small and hidden, but there are several warning signs that can alert you before the damage becomes too serious:

1. Unexplained Increase in Water Bills: A sudden spike in your water bill is one of the earliest indicators of a hidden leak. Even a small drip, running constantly over days or weeks, can add up to hundreds or thousands of liters of wasted water. If your usage doesn’t match your lifestyle or household habits, it’s time to investigate.
2. Visible Water Stains or Discolouration: Stains on walls, ceilings, or floors are often the first visible signs of a leak. Water marks may appear as yellow or brown patches, peeling paint, or bubbled wallpaper. These signs indicate moisture has penetrated building materials and should be checked immediately.
3. Damp or Musty Odours in the Home: Even if you can’t see water, a persistent damp or musty smell is a strong clue that moisture is accumulating somewhere in your home. These odours often indicate hidden leaks behind walls, under floors, or in ceilings.
4. Mould or Mildew Growth: Mould and mildew thrive in damp environments, so their presence is a clear warning that water is collecting somewhere. Mould not only damages surfaces and materials, but it also poses serious health risks. Mould can be black, green, brown, or even white, depending on the type and surface it’s growing on. Mildew is usually white or gray and powdery.
5. Dripping Sounds or Running Water When Everything is Off: If you hear water running, dripping, or trickling when all taps, appliances, and water systems are off, something is leaking. This may be a leak in pipes, toilets, or hot water systems that needs attention ASAP.
6. Unexpected Low Water Pressure: A sudden drop in water pressure can signal a leak somewhere in your plumbing. Water escaping from pipes reduces the flow that reaches your taps and showers, making everyday tasks more difficult and pointing to potential hidden damage.

How to Perform Basic Leak Detection Yourself

You don’t always need expensive equipment to catch a leak. Many leaks can be spotted with careful observation and a few simple tools. Here’s how to check your home step by step:

1. Checking Your Water Meter for Irregular Usage

Start with the simplest method: your water meter. Your water meter, usually located near the front of your property or in a meter box, measures the total water usage for your home. By tracking changes when no water is being used, you can identify potential leaks.

1. Turn off all water-using devices: Make sure taps, appliances, irrigation systems, and any other water sources are completely off. This ensures that any movement on the meter is due to a leak and not normal usage.
2. Record your meter reading: Take note of the numbers on your water meter. Some meters have a digital display, while others have a mechanical dial.
3. Wait and observe: Leave all water off for 15–60 minutes. The exact time can vary depending on how quickly you want to detect a leak (longer waits can catch slower leaks).
4. Check the meter again: Compare the new reading with your initial recording. If the numbers have changed, even slightly, it’s a strong indication that water is escaping somewhere in your system.

2. Inspecting Visible Pipes and Joints

Many leaks start at the pipes and joints you can see.

Where to check:

• Under sinks: Cabinets often hide leaking pipes. Look for moisture, wet spots, or puddles around supply lines and drain pipes.
• Around toilets: Connections behind the toilet tank and the base of the toilet can develop leaks. Check for damp flooring or discolouration that might indicate water escape.
• Hot water lines: Pipes connected to hot water systems are prone to corrosion and pinhole leaks. Examine the joints and fittings for rust or mineral deposits.

What to look for:

• Corrosion or rust: Indicates aging pipes or fittings that could fail soon. Even minor rust should be addressed to prevent leaks.
• Moisture or wet patches: Small damp areas on floors, walls, or pipe surfaces often indicate a slow leak. Run a dry cloth along pipes and fittings to detect dampness.
• Mould or mildew around connections: Mould growth is a sign of prolonged moisture exposure and often points to a hidden or slow leak.

Don’t forget outdoor taps and hoses! These are easy to overlook but can be a source of leaks or false positives during testing. Check garden taps, irrigation hoses, and hose connections for cracks, drips, or worn washers. Be aware that water escaping from outdoor pipes may soak the surrounding soil, making leaks less obvious

3. Monitoring Appliances and Water-Using Fixtures

Appliances are common culprits for leaks. Regularly check:

• Washing machines: Check hoses for bulges, cracks, or loose connections. These hoses can deteriorate over time, and a burst hose can cause sudden flooding. Ensure the hoses are firmly attached and replace any that show signs of wear.
• Dishwashers: Look for drips at the bottom or around the back of the unit. Leaks can occur from door seals, hose connections, or internal valves, often pooling underneath without being immediately noticed.
• Irrigation systems and garden taps: Outdoor water systems are prone to leaks due to wear, UV exposure, or damage from tools and landscaping. Inspect hoses, sprinkler heads, and pipe connections regularly.
• Cooling systems and evaporative air conditioners: Check for water pooling around units and ensure that drainage channels are clear. Even minor blockages can cause water to overflow or seep into surrounding areas.
• Water storage tanks and hot water systems: Examine tanks, pipes, and valves for any signs of corrosion, drips, or damp patches. Leaks from these systems can be costly due to both water and energy loss.

Even small leaks from these devices can waste hundreds of litres of water over time.

4. Detecting Roof and Ceiling Leaks

Check your ceilings and roof for early warning signs:

• Water stains or discolouration: Yellow, brown, or rust-colored spots on your ceiling or walls often indicate that water has penetrated the roof. Even small stains can signal a developing problem.
• Damp or sagging patches: Moisture can cause ceilings to feel soft or spongy. Sagging sections may appear as bulges or uneven surfaces, a clear indication that water is pooling above.
• Musty odours: Even if you don’t see water, a persistent damp or earthy smell can indicate a hidden leak. These odors often come from mold or mildew growing in areas with trapped moisture.

Rainy days provide the best opportunity to spot leaks, as active water entry often reveals itself through drips or wet spots. Look for water seeping through ceilings, around roof vents, skylights, or chimneys.

5. Food Colouring Test for Toilet Leaks

Toilets are one of the most common sources of hidden water waste in the home. Fortunately, there’s a simple way to check if your toilet is leaking, and you don’t need any special tools.

1. Add food colouring to the tank: Pour a few drops of food colouring into the toilet tank, not the bowl. The coloured water will act as a visual tracer to reveal leaks.
2. Wait without flushing: Leave the toilet alone for 15–30 minutes. During this time, do not use the toilet or flush it. This allows any water that’s escaping past the flapper valve to show up in the bowl.
3. Check the bowl for colour: If you see the food colouring in the toilet bowl, it’s a clear sign that the flapper valve is leaking. This means water is constantly seeping from the tank into the bowl, wasting a significant amount of water.

6. Finding Hidden or Underground Leaks

Leaks that occur inside walls or underground are often the most difficult to detect. Because they are hidden from plain sight, they can go unnoticed for weeks or even months, causing extensive damage before anyone realises there’s a problem.

Underground leaks

• Unusually green patches or soggy soil: Constant water escaping underground can create areas of lush grass or mud in otherwise dry parts of your yard.
• Pooling water: Puddles or standing water that appear even when it hasn’t rained may indicate a broken or leaking pipe.

Professional detection tools can pinpoint underground leaks without unnecessary digging:

• Acoustic leak detectors: These devices use sensitive microphones to pick up the sound of water escaping from pipes beneath the surface.
• Thermal imaging cameras: By detecting temperature changes in the soil or ground surface, these cameras can highlight “hot spots” where water is leaking.
• Tracer wires and probes: These tools identify breaks or conductivity changes in buried pipes.
• Underground cameras: Small cameras with transmitters can inspect the interior of pipes to locate cracks or leaks without digging.

Leaks inside walls

• Moisture meters: These allow you to measure dampness inside plaster or drywall without opening up walls.
• Thermal imaging: Temperature variations caused by leaking water can show up on thermal cameras, revealing concealed pipe issues.
• Acoustic sensors: These detect water movement or hissing sounds inside pressurized pipes behind walls.
• Visual clues: Watch for peeling paint, bubbling wallpaper, discolouration, or changes in wall texture. Small spots may be the first signs of a developing leak.

7. Hot Water System and Evaporative Air Conditioner Checks

These systems are common but often overlooked sources of leaks. Because they are typically hidden or integrated into your home’s structure, leaks from these systems can go unnoticed for weeks, even months!

Hot water systems, including storage tanks and instant water heaters, have multiple components that can fail over time. One of the most important parts to monitor is the relief valve pipe, which is designed to control pressure within the system:

• Relief valve leaks: A faulty or worn relief valve can allow water to escape continuously, often unnoticed, which can cause damp patches or corrosion around the unit.
• Signs to watch for: Damp flooring or staining around the base of the system, unusual pooling of water, or unexplained increases in water bills may indicate a leak.
• Maintenance tip: Periodically test the relief valve by lifting the lever to ensure it operates correctly, and inspect the discharge pipe for signs of corrosion or dripping.

When To Call A Leak Detection Specialist

DIY leak detection is a useful first step, but knowing when to call in a professional can save you time, money, and prevent extensive damage. Some leaks are subtle, hidden, or require advanced tools to locate, and attempting to fix them yourself can sometimes make the problem worse.

Leak detection specialists use advanced tools like acoustic sensors, infrared cameras, and tracer gases to pinpoint leaks with precision. These technologies can locate water escaping behind walls, under floors, or underground—without causing unnecessary damage to your property.

While DIY methods may seem cost-effective at first, they often miss hidden problems or can even make damage worse. Most plumbing experts recommend:

• Yearly inspections for peace of mind and early detection
• Immediate checks whenever you suspect a leak

Beyond leak detection, professional services provide a comprehensive overview of your plumbing system’s health. Identifying weak points and potential future issues helps prevent major problems and extends the lifespan of your plumbing.

Stay Ahead Of Plumbing Problems

Water leaks may seem minor at first, but even a small drip can quickly escalate into serious damage and unnecessary expenses. The key to protecting your home is early detection. Simple DIY methods, like checking your water meter and regular inspection, can help you spot common leaks before they become major issues.

For trickier or hidden leaks, professional leak detection specialists bring the right expertise and advanced equipment to locate problems without damaging your property, saving you money and stress in the long run.Need help finding or fixing a leak? At Hardie & Co, we provide fast, reliable, and personalised plumbing services that make solving leaks easy. Get in touch today and keep your home safe, your water bills down, and your peace of mind intact.