Start with when the water appears
Water present even when fixtures have not been used can point toward a pressurised supply leak or another continuous source. Water that appears only during showering, draining or heavy rain suggests a different set of possibilities. The timing is evidence, not a final diagnosis.
Test individual sources where practical
Controlled testing can isolate supply fittings, wastes, overflows and wet-area surfaces one at a time instead of flooding the whole area. This can reduce unnecessary opening and help separate plumbing faults from waterproofing, sealant or building-envelope defects.
Keep reinstatement separate from diagnosis
Even when the source is found, repairing a pipe may not repair damaged waterproofing, ceilings, tiles or finishes. A clear scope should state what defect is being repaired and what making-good work is included or excluded.
Related information
Damp Wall Near Plumbing
Dampness near pipe routes can result from a concealed leak, waste leak, waterproofing failure, condensation or moisture from another source.
How to Use a Water Meter as a Leak Clue
A meter can show unexplained water use, but the result must be interpreted carefully before it is treated as proof of a concealed leak.
Leak Detection
Hidden leaks are best approached as a diagnosis problem. Start with evidence such as meter movement, pressure loss, damp patterns and the plumbing layout before opening finishes.
Shower & Bath Plumbing
Shower and bath leaks can come from supply fittings, wastes, traps, seals, waterproofing or surrounding finishes. Diagnosis should distinguish plumbing leakage from building-envelope or waterproofing failures.