Maida Vale

Three pipe systems, one building

An Edwardian mansion block is not a big house. It is a set of separate legal properties stacked around shared infrastructure, and the plumbing follows the same logic. Before anyone can usefully answer "who pays", the leak has to be assigned to one of three systems.

System	What it is	Usually whose
Rising main and vertical risers	The incoming supply and the vertical pipes in the stack or duct serving every floor, plus communal tanks where they survive	The freeholder or management company, funded through service charge
Horizontal branch	The run from the riser along the corridor or through the structure to your flat's stop valve	Depends entirely on where your lease draws the demise
Inside the demise	Everything from your stop valve onward: bathroom, kitchen, heating, waste	Yours

The middle row is where almost every dispute in these buildings lives, and no general rule settles it. The lease settles it.

What the law puts on the landlord, and what it does not

Where a flat is let, section 11 of the Landlord and Tenant Act 1985 implies a covenant on the landlord to keep in repair the structure and exterior of the dwelling, including drains, gutters and external pipes, and to keep in repair and proper working order the installations for the supply of water, gas, electricity and sanitation. Where the dwelling forms part of a larger building, that obligation extends to parts of the building the landlord owns or controls that serve the dwelling.

Two limits matter. It is an implied term of a lease, so it sits alongside whatever the lease itself says rather than replacing it. And it is about repair, not about who is at fault for damage. A landlord obliged to repair a communal riser is not thereby liable for your ruined floor. Those are two different questions with two different answers, and conflating them is how these things end up taking six months.

Reading the symptom to find the system

Before the managing agent is called, it is worth spending ten minutes narrowing it down, because the first question they will ask is whether it is coming from inside a flat.

Points at the communal system

• Water appearing in a hallway, stairwell, lift lobby or riser cupboard rather than in a flat.
• Staining that runs down several floors in the same vertical line, in the corner of the same room on each floor.
• Pressure or flow dropping across more than one flat at the same time.
• A damp patch that is worse when the block is busy in the morning and eases overnight.

Points at one flat

• Damage confined to one ceiling directly below one wet room.
• It follows use: worse after a bath or a shower upstairs, nothing overnight.
• Clean warm water rather than cold, which pushes it towards heating or hot supply rather than a cold riser.

If it is the ceiling below a neighbour's bathroom, start at a leak from the flat above. If it is a vertical line down the building, it is a riser until proven otherwise.

Who is allowed to instruct us

This is the practical bottleneck in a block, and it is worth understanding before you phone anyone. A leaseholder can instruct work inside their own demise. Work on communal pipework, in risers, in ducts, in the roof space or in the basement tank room has to be instructed by whoever holds that obligation, normally the freeholder, the residents' management company or the managing agent acting for them.

We are regularly called by a leaseholder whose ceiling is ruined, asked to open a riser cupboard two floors up, and cannot lawfully do it. That is not a technicality we hide behind; it is the reason the first thing we ask on a block job is who is instructing.

What makes the call go smoothly:

• Written instruction from the agent or RMC where communal pipework is involved, even a short email.
• Access arranged in advance to the riser cupboards on the affected floors, not just to the flat with the damage.
• The location of the block's main stop valve, and confirmation that it works. In a lot of these buildings it has not been turned in twenty years.
• Whether the block is on a shared supply, which Thames Water treat as jointly maintained by the properties it serves.

Why detection in a mansion block is a different job

The structure is against you. Solid brick cross-walls, concrete or timber-and-ash floors, lath and plaster ceilings, and pipework that was retro-fitted in at least three separate eras through whatever route was available at the time. Water entering at a riser on the fourth floor can emerge in a second floor hallway with nothing visible in between.

What actually works here is staged. Isolate systems one at a time and watch the meter and the pressure, which separates the communal cold supply from heating from a single flat's plumbing without opening anything. Then thermal imaging along the suspected run, which reads temperature difference through plaster and screed. Then, on a drained section, tracer gas, which is the only method that reliably finds a small cold-water loss inside a masonry wall. Acoustic work is often disappointing in these buildings because the structure carries noise so well that everything sounds close.

What we will not do

We will not tell a leaseholder that their neighbour is liable, and we will not write that into a report. What a report can properly say is where the water came from, what failed, how long it had been running and what it damaged. That is the evidence the freeholder's insurer and the leases need in order to allocate cost, and it is worth more than an opinion on fault, which nobody will accept from a plumber anyway. There is more on how that report is put together in our insurance claims pages.

Block work is charged at £150 an hour, fixed before we attend, and we produce a written report on communal jobs as standard because the agent will need one.