Quick answer
There are five reliable signs of a hidden leak: a rising water bill with unchanged usage, a meter that keeps ticking with every tap closed, damp patches on walls or floors, unexplained warm spots on tiles, and mould or peeling paint in one specific area. The meter test is the definitive one — if the dial moves with everything in the house closed, water is escaping somewhere between the meter and your taps.
Common causes
- Pinhole corrosion in copper pipe, common in homes over twenty years old
- Failed joint under the slab, where the leak stays hidden until it reaches a wall
- Cracked geyser inlet or outlet connection weeping into the ceiling
- Toilet inlet valve leaking silently into the bowl — the most common and most missed
- Perished washing-machine or dishwasher inlet hose behind the appliance
- Cracked irrigation line running continuously under the garden
What you can do now
- 1Close every tap and appliance, note the meter reading, wait two hours and read it again — any movement means a leak
- 2Dye-test each toilet: a few drops of food colouring in the cistern, and colour appearing in the bowl without flushing confirms a leaking inlet valve
- 3Feel walls and floors for warm patches, which indicate a hot-water line rather than a cold one
- 4Isolate the irrigation system at the manifold and repeat the meter test to rule the garden in or out
- 5Check behind the washing machine and dishwasher, where perished hoses weep unnoticed for months
When to call a professional
If the meter advances with everything closed, book leak detection rather than guessing where to open a wall. Acoustic and thermal equipment locates the leak without breaking tiles or lifting a slab, and the detection cost is usually credited against the repair. Call sooner if you can see damp spreading, since the damage compounds far faster than the leak itself.
Typical cost in Johannesburg
Leak detection R950–R1,800
Indicative ranges only. We provide written, itemised quotes before any work.
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