Leak Symptoms
Identify common signs of hidden leaks and find the right investigation route.
These guides explain when symptoms such as pressure loss, high water bills, damp patches or ceiling stains should be investigated by specialist leak detection engineers.
Start Here
Hidden leaks can show up through several broad warning signs. Choose the closest match below, then use the symptom guides to decide whether specialist investigation is needed.
Problem Guides
Symptoms linked to boilers, central heating circuits and underfloor heating systems where pressure loss or shutdowns may point to a concealed leak.
Repeated central heating pressure loss can indicate a hidden heating pipe leak or sealed system fault.
Read guideUnderfloor heating pressure loss can point to a concealed UFH pipe leak or manifold issue.
Read guideRepeated boiler shutdowns can be linked to pressure loss, hidden heating leaks or sealed system faults.
Read guideHeating and hot water failures can sometimes be linked to pressure loss, boiler lockouts or hidden pipework leaks.
Read guideRepeated boiler pressure loss can indicate a hidden central heating or underfloor heating leak.
Read guideGuidance for unexplained water usage, running meters and high bills that may indicate a hidden mains water or supply pipe leak.
A sudden increase in water usage can point to a hidden mains water or supply pipe leak.
Read guideA high water bill without visible water damage can indicate hidden supply pipe or concealed pipework loss.
Read guideA moving water meter when outlets are off can indicate a hidden supply pipe leak.
Read guideCommon signs of moisture movement, escape of water or water ingress where the visible damage may be away from the leak source.
Damp patches can be caused by concealed pipework leaks, water ingress or moisture tracking.
Read guideDamp below timber floors can be linked to hidden pipework leaks, heating leaks or subfloor moisture movement.
Read guideCeiling staining may indicate a bathroom leak, pipework issue or escape of water above.
Read guideNext Steps
Every property and leak is different, but most investigations follow a similar route from recognising a symptom to obtaining a professional diagnosis.
Choose the guide that most closely matches what you are experiencing, such as boiler pressure loss, damp patches, rising water bills or a constantly moving water meter.
Follow any simple checks recommended within the guide. These checks may help rule out obvious causes, but they cannot always confirm whether a hidden leak exists.
If the cause remains unclear or the problem continues, a specialist leak detection investigation can help identify the likely source.
View servicesEngineers select the most appropriate non-destructive investigation techniques based on the property, symptoms and suspected pipework route.
View technologyOnce the likely source has been identified, the findings can guide the next step, whether that is targeted access, a plumbing repair or further property investigation.
Read a relevant guideCommon Questions
These answers clarify common points before you move from symptom guides to professional advice. For broader questions, visit the main FAQ or compare service routes in the Comparisons hub.
No. Damp patches can be caused by concealed leaks, but they may also result from condensation, penetrating damp, ventilation issues or other moisture sources. The pattern, location and whether the patch changes over time all matter.
Yes. Boiler pressure loss can be linked to expansion vessel faults, pressure relief valve issues, air in the system or other heating-system problems as well as concealed leakage. Repeated or unexplained pressure loss usually needs closer investigation.
A plumber may be suitable when the fault is visible, accessible or clearly related to a fitting. A leak detection specialist is more appropriate when the source is concealed, uncertain or likely to require non-destructive investigation before access work.
Non-destructive methods can often narrow down or locate hidden leaks before floors or walls are opened, but no single technique is suitable for every property or symptom. The investigation method should be selected based on the evidence.
Consider the symptoms together rather than treating each one as separate proof of a leak. For example, pressure loss, staining and moisture readings may point to the same issue, but the cause still needs to be confirmed before repairs are planned.
Professional Diagnosis
If the guides point to a concealed or uncertain source, a leak detection survey can bring the symptoms together and provide clear findings before access or repair decisions are made.
