You notice a damp patch on the wall near your shower. Maybe there is a faint musty smell that will not go away, no matter how often you clean. Or perhaps the grout lines have turned an odd shade of dark that scrubbing just does not fix. Sound familiar?
If you are a homeowner in Sydney, you are not alone. In fact, many Sydney residents look into shower waterproofing in Sydney after spotting these exact warning signs, and the smart ones act on it quickly.
Here is the thing: what looks like a minor bathroom issue can quietly turn into a major structural problem. Water has a way of travelling far from its source, weakening subfloors, rotting timber, and encouraging mould growth before you even realise what is happening. The good news is that you can start with a simple DIY leak test at home!
Table of Contents
What You’ll Need Before You Start
This test does not require any special skills or equipment. Before you get started, make sure you have these on hand:
- Waterproof tape or a drain plug
- A marker or masking tape to mark the water level
- A timer
- A notepad to jot down what you find
Nothing fancy — just a few things you likely already have at home. Once you have these on hand, you are ready to go.
Step-by-Step: How to Do a Shower Leak Test at Home
The shower leak test is one of the most straightforward ways to check whether your shower is losing water where it should not be. Here is how to do it properly.
Step 1: Plug the drain using a drain stopper or waterproof tape.
You want the drain completely blocked. If water quietly slips out through it, the test tells you nothing — any water loss needs to come from the walls or base, not the drain itself.
Step 2: Fill the shower base with water to about 20mm depth and mark the water level.
Fill it up, then stick a piece of masking tape on the wall right at the waterline, or use a marker if you prefer. That mark is everything, so get it right.
Step 3: Wait 24 hours without using the shower.
Now just leave it. A full day, untouched. Keep the bathroom door shut if you can. An open, ventilated room will cause some of that water to evaporate, which could throw off your reading.
Step 4: Check the water level.
After 24 hours, return and compare the current water level against your mark. Has it dropped? A tiny drop is probably just evaporation. But if the level has fallen noticeably, water is getting out somewhere it should not be.
Step 5: Inspect the surrounding areas.
Get out of the shower and check the floor around it. Any dampness is a red flag. Press your hand against the nearby walls and feel for anything soft or see if the paint looks off. Got a room underneath your bathroom? Go check that ceiling for wet patches or watermarks.
If the water level barely moved and nothing around the shower looks dodgy, your shower is likely holding up fine.
What to Look For Beyond the Water Level
The leak test is handy, but it does not show you everything. While you are in the bathroom, keep an eye out for these additional warning signs:
- A soft or spongy feeling underfoot near the shower base
- Grout lines that look darker than usual or are visibly cracked and crumbling
- Mould or mildew growing at the base of walls, not just surface grime, but growth that keeps coming back
- Peeling paint or bubbling on walls adjacent to the shower
- A persistent musty odour that lingers even after the bathroom has been aired out
That last point about mould is worth taking seriously. Beyond the damage to your home, the possible health impacts of mould include respiratory issues, allergic reactions, and other concerns, particularly for children, the elderly, or anyone with asthma.
When the Test Says “You’re Fine” But You Probably Aren’t
A passed test does not always mean your shower is problem-free. Waterproof membranes can fail gradually, and a slow deterioration will not always show up in a static leak test. Leaks are often intermittent, meaning they only occur under the water pressure of an active shower, not when water is sitting still.
If your test came back clean but you are still noticing musty smells, recurring mould, or any of the visual signs listed above, do not dismiss them.
Don’t Let a Small Leak Drain Your Wallet: Act Now!
Water damage does not pause while you wait and see. It works quietly and consistently, spreading further with every shower you take.
When you catch a problem early, the repair options are far less disruptive and far less expensive. In some cases, a professional can apply waterproofing solutions over existing surfaces without a full tile removal. In more serious situations, waterproofing boards and a complete membrane replacement may be required to properly protect your home.
Either way, the sooner you act, the better the outcome. If your flood test raises concerns, get an expert to assess the situation before a small leak becomes a very costly repair!
