How to Spot a Water Leak: Signs, Detection Methods and What to Do
A hidden water leak can push up your bill for months and damage walls and floors before anyone notices. Spotting it early saves both water and repair costs. Here is how to recognise a leak and get it located properly.
Signs of a water leak
- A rising water bill although your usage has not changed
- Damp patches, bubbling paint or a musty smell on walls, ceilings or floors
- The sound of running water with every tap closed
- The rooftop tank empties faster than expected or the pressure pump (hydrophore) keeps switching on by itself
- A spot in the garden that never dries
Even one of these is worth having checked.
A simple meter test
Close every tap, cistern and water-using appliance in the house. Note the meter reading and use no water for an hour or two. If the reading has changed, there is a leak somewhere in the system.
In homes with a tank and pressure pump, a pump that runs while no tap is open means the same thing.
How is a leak located?
Today the leak can usually be found without breaking tiles. Depending on the job the plumber uses a thermal camera, an acoustic listening device, a pressure test or a moisture meter. Once the spot is pinpointed, only that point is opened — which keeps repair and re-tiling costs down.
What to do when you notice a leak
- Close the main valve if the water damage is growing
- Switch off the breaker if sockets or appliances are getting wet
- Photograph the damp patches and the meter reading — useful for the plumber and, if needed, your insurer
- Do not break walls on a guess; have the leak located first
What affects the price?
A plumber cannot give a firm price without seeing the site; the main factors are:
- The detection method and the size of the property
- Where the leak is (inside a wall, under the floor, a garden line)
- Whether tiling, plaster or paint is needed after the repair
- The pipe type and the length that needs replacing
Frequently asked questions
Do walls have to be broken to find a leak?
Usually not. Thermal and acoustic devices locate the leak and only that point is opened.
My pressure pump keeps running — could it be a leak?
Yes; a pump that runs while no water is being used is a common sign of a leak in the plumbing or the tank line. A faulty check valve on the pump can also cause it.
How long until the damp dries after the repair?
It depends on the wall thickness and ventilation and can take a few weeks. Repaint only once the wall is completely dry.