The source of a hidden water leak is usually found by gathering clues, checking how and when the problem appears, and narrowing down which part of the plumbing is losing water. The aim is to find the cause with as little disruption as possible before any repair is planned.
Every leak is different, so the approach depends on the property and the symptoms. Knowing what the process usually involves can help you prepare and know what to expect.
Starting With the Clues
An investigation often begins with questions. When did you first notice the problem? Does the damp appear all the time, or only when a shower, bath or appliance is used? Has your water bill risen, or is your meter moving when nothing is on?
The answers can point to the type of leak. Water that only appears when a shower runs suggests something different from a damp patch that is there day and night. A plumber will also look at the damage itself, although damage alone does not identify where the leak starts.
Narrowing Down the Area
Water can travel along pipes, joists and walls before it shows, so a stain may be some distance from the source. A plumber may look at where pipes are likely to run, check visible pipework, joints and valves, and look in cupboards, lofts or access panels where pipes can be seen.
Comparing what is happening on different floors or in different rooms can also help. A problem that affects one bathroom only may point to pipework or fittings in that area.
Parts of the system may be isolated or tested one at a time to see whether the problem stops. This can help show whether the leak is on the cold supply, hot water pipework, a waste pipe or a fixture.
When More Investigation Is Needed
Some leaks are easy to trace once the right area is found. Others are harder, such as a slow leak under a solid floor or a supply pipe leak underground. Different methods may suit different situations, and sometimes small areas may need to be opened up to confirm the source.
In some cases the problem turns out not to be plumbing at all. Condensation, rainwater from outside or a fault in the building may need a different trade.
What You Can Do to Help
Note when you first saw the problem, take photographs and keep a record of any meter readings. Clear access to the affected area, the stopcock and any cupboards or panels where pipework can be reached.
Our page on professional leak detection explains how uncertain or concealed leaks are investigated before a repair is arranged.
If you have a leak you cannot find in your Poole property, a plumber can talk through the signs and explain how the source might be narrowed down.