Investigating Water Leaks in Apartment Buildings
Leaks in apartment buildings often appear a long way from where the water gets in. This guide covers what to record, the common types of leak, and what each test method can and cannot show.
What to record when a leak appears
Good notes save investigation time. Residents and managers can record:
- Where the water or staining appears, with photos and a rough measurement of its size
- When it started and whether it is getting bigger
- Whether it appears during or after rain, or when a shower, bath, washing machine or tap above is used
- Whether it is constant, intermittent or only at certain times of day
- Which apartments are above or beside the affected area, and how to contact them
Rain-related leaks versus supply or drain leaks
Leaks that appear only during or after rain usually point to the building envelope or roof drainage — roofs, box gutters, balconies, windows or facades. Leaks that continue in dry weather are more likely to come from water supply pipes, which are under pressure, or from waste and drain pipes, which leak when a fixture is used.
This is a starting point, not an answer. A blocked balcony outlet can behave like a rain leak, and a leaking shower may only show when that shower is used. That is why investigation usually combines several methods.
What each test method can show
No single method gives a definitive answer on its own. Some leaks need more than one visit, or need an area opened up once non-invasive testing has narrowed the location.
- Thermal imaging shows surface temperature differences that can indicate moisture or hidden water lines. It does not see through walls and can be affected by sunlight, air conditioning and building materials, so results need interpreting alongside other tests.
- Moisture mapping uses meters at many points to show how far moisture has spread and where readings are highest, which helps narrow the likely source.
- Pressure testing isolates sections of the water supply to confirm whether a pressurised pipe is leaking.
- Controlled spray testing applies water to one area at a time — a window, balcony edge or shower — to see whether that area lets water in. Testing in sequence helps separate one possible source from another.
Coordinating access
The source of a leak is often in a different apartment from the damage. Investigations go faster when the manager arranges access to the affected apartment and the ones above and beside it, and lets residents know what testing involves — for example, that a shower or balcony may need to be kept dry beforehand or used during a test.
Reporting
A useful leak report records what was tested, what was found, photos of readings and locations, the likely source, and recommended repairs with a quote. It should also note anything that could not be tested.
Questions of who is responsible for a repair — an individual lot owner or the owners corporation — depend on the building's plan of subdivision, rules and the specific circumstances. A plumber's report can describe where the leak originates, but managers should seek appropriate advice on responsibility.