How to tell if your shower is leaking

The quick checks you can do yourself

You don’t need equipment to spot the early signs of a leaking shower. Start with what you can see and smell:

• Look next door. Check the wall or floor of the room backing onto the shower for damp patches, discolouration or bubbling paint.
• Tap the tiles. Tiles that sound hollow or ‘drummy’ often have moisture sitting behind them.
• Check the grout and silicone. Grout that keeps going mouldy or crumbling, and silicone that’s split or peeling, are common entry points.
• Trust your nose. A bathroom that smells musty when it’s been dry for hours usually has moisture trapped somewhere.

For a simple test, dry the floor outside the shower recess, run the shower for ten minutes, and check whether any moisture appears beyond the recess. Water showing up where it shouldn’t is a strong sign the recess isn’t holding water the way it should.

Signs the leak has been going a while

Some signs only appear once a leak has been quietly running for months:

• Efflorescence — chalky white salt deposits on tiles, grout or the wall below, left behind as water evaporates.
• Swollen or lifting skirting and flooring in the next room.
• A stain on the ceiling below an upstairs shower — often the first thing people notice.
• Lifting or loose tiles in the recess itself.

The longer a shower leaks, the further the water travels and the more it costs to put right — which is why catching it early matters.

Where shower leaks usually come from

Almost every shower leak traces back to one of a few places: a failed or aged waterproofing membrane under the tiles, cracked grout or perished silicone, a leaking hob or screed with poor fall, or a loose fitting like the mixer or floor waste. Telling which one is the actual source is the whole job — and it’s why guessing (and re-tiling the wrong thing) so often fails.

If you’ve got any of the signs above, a professional shower leak detection inspection can pinpoint the exact failure point without lifting a tile, using moisture mapping and thermal imaging.