How do you find a water leak inside a wall?

A hidden water leak inside your walls can lead to costly damage if left undetected. Stains, peeling paint, musty smells and rising water bills are all red flags that something isn’t right. Catching a leak early can save you from structural damage, mould growth and expensive repairs.

This guide walks you through the key warning signs, simple DIY tests and when to call in a professional to stop the leak before it gets worse.

Here are some common signs that you might have a hidden leak inside a wall:

• Discolouration and staining: Yellow, brown or dark patches on your walls are often a clear sign of water seeping through. Plus, they can spread if left unchecked.

• Peeling paint or wallpaper: Moisture behind the wall can cause paint or wallpaper to bubble, blister or peel. If you see this, it might be due to a hidden leak.

• Mould growth: Dark spots or a musty smell on the wall are common signs of mould or mildew, which thrive in damp conditions caused by leaks.

• Musty odours: A damp, musty smell indicates trapped moisture behind walls.

• Unexplained increase in water bills: A sudden spike in your water bill could point to a hidden leak, as even small leaks can waste significant amounts of water.

Catching these signs early can help you avoid costly repairs and further water damage. If you notice any of these issues, investigate further and consider professional help to find and fix the leak before it worsens.

In order to pinpoint where a leak is, you can quietly listen near suspected areas for faint dripping or running water sounds. Even small leaks inside a wall can create subtle noises.

Next, you could try performing a water meter test by following these steps:

1. Shut off water usage - turn off all water sources in your home, such as taps, toilets and appliances.

2. Check the meter - record the initial water meter reading, then wait a few hours without using water.

3. Confirm a leak - if the meter reading increases despite no water usage, there’s likely a leak somewhere in the system.

You can also conduct a water pressure test:

1. Turn off water sources - make sure all water fixtures are off, including taps and showers.

2. Measure pressure - attach a pressure gauge to an accessible outdoor tap to check the water pressure.

3. Monitor pressure changes - if pressure drops after a few hours, it could indicate a hidden leak in the plumbing system, including behind walls.

If you can’t locate the leak after visual inspections, listening for sounds or performing water meter and pressure tests, it’s time to call a professional. Plumbers have specialised tools and expertise to pinpoint hidden leaks in walls more effectively.

If water damage continues or worsens despite your efforts, professional help is also crucial. Unrepaired leaks can cause severe damage to walls, ceilings, flooring and your home’s structure. A plumber will not only find and fix the leak but also prevent further damage and avoid future issues.

In these situations, the quicker you act, the better the outcome will be. If you’ve identified a water leak but can’t seem to fix the issue on your own, find a plumber using our search tool to resolve the problem quickly and efficiently.