Apartment Water Leaks: Breaking the Evidentiary Deadlock

16 October 2026

It often happens that when a leak is hidden inside the building envelope, or tracking along a concrete slab separating two floors, both an OC and an upstairs neighbour may try to hide behind the lack of definitive proof.  However, the Victorian Civil and Administrative Tribunal (VCAT) will not allow an OC or neighbour to escape liability simply because the structural source of the leak is unknown, or difficult to ascertain. 

Weaponising Section 16(5) Against a Neighbour

An upstairs neighbour cannot simply shrug their shoulders and claim they do not know whether the water is coming from their balcony, or the building's exterior.  Under Section 16(5) of the Water Act 1989, an occupier becomes personally liable for damage if they fail to take reasonable steps to stop an unreasonable water flow after being formally notified.  Once on notice, a refusal to permit a plumber access, or failure to properly investigate is no longer an excuse.  Instead, it is an issue of legal liability.

Forcing the Owners Corporation’s Hand

Similarly, an OC cannot use an unproven leak source as a shield to avoid investigation and maintenance.  Victorian strata principles dictate that if water passes through, pools on, or enters via common property elements (like the external building facade, roof space, or the structural concrete ceiling above), the OC is failing its strict duty to maintain that common property, as mandated by Section 46 of the Owners Corporations Act 2006 (Vic).  Where the origin of the leak is ambiguous, the legal burden often shifts to the OC to actively prove the water is not coming from a defect in the building envelope, rather than forcing the affected owner to spend many thousands trying to prove it is.

Tactical Playbook

Where the builder is long gone, no DBI policy exists and there is continuing stone-walling by the upstairs neighbour and the OC, an application can be filed in the VCAT Building and Property List, naming them both as co-respondents.

Start building a formal legal case and seek urgent legal advice to:-

1. Obtain the official property plan via Landata.  This will identify precise boundaries between private lots (including balcony air-space and internal walls) and the OC's common property building envelope.
2. Provide formal notice (citing Section 16 of the Water Act) of an unreasonable water flow and resultant damage to both the upstairs owner and the OC manager, demanding they urgently engage an expert at their cost to ascertain the source of the water leak.
3. If necessary, launch a dual-target VCAT claim seeking a mandatory injunction that they jointly appoint an expert and a decision on how the repair bills and damages are to be split between them.

Emanuel Tumino

Partner