Cause and Origin: The Leak Report a Landlord or Managing Agent Can Actually Use

What "cause and origin" means, and why insurers ask for it

Cause and origin is two separate findings in one phrase. Origin is the physical point the water escaped from — this joint, this length of pipe, this seal. Cause is why it failed — mechanical damage, corrosion, freezing, a failed seal, movement, poor workmanship. A report that gives one without the other is half a report.

Insurers ask for both because a buildings policy responds to a sudden escape of water and generally not to gradual deterioration or want of maintenance. The origin tells the adjuster which part of the building the damage flowed from and therefore what is covered. The cause tells them whether the event falls inside the policy at all. "There is a leak in the bathroom" answers neither question, which is why that sentence, attached to an invoice, is the single most common reason a trace and access claim stalls.

For a landlord or managing agent the same document does a second job entirely. It settles who pays. In a block, the difference between a failure in a communal riser and a failure in the pipework serving one flat is the difference between a buildings insurance claim and a leaseholder's bill, and that difference is decided by a finding of origin.

The two-stage survey: what stage one rules out

We survey in two stages because ruling things out is cheaper and more defensible than hunting for the answer straight away. Stage one narrows and eliminates. Stage two locates. The report has to show both, because the eliminations are what make the final finding credible.

Stage one is non-destructive and largely instrumental. The meter is read over a fixed interval with all outlets closed to establish whether water is being lost from the supply at all. The heating system is isolated and its pressure watched separately, because a dropping boiler gauge is as likely to be a failed expansion vessel or a discharging pressure relief valve as it is a leak. Moisture readings are taken across the affected area and, where the finish allows, at depth — a surface meter reading on plaster tells you the plaster is wet, not where the water came from. Ambient temperature and relative humidity are recorded, because a damp wall in a poorly ventilated flat in February is a condensation candidate until proven otherwise.

By the end of stage one a competent survey can normally say what it is not: not the supply, or not the heating, or not a leak at all but a condensation or penetrating damp problem. Those exclusions belong in the report in writing. An adjuster reading a report that says "mains supply eliminated: meter static over 90 minutes with all outlets closed" is being handed evidence. One reading "leak found in kitchen" is being asked to take it on trust.

Stage two is the location work — acoustic listening and correlation on pressurised pipework, thermal imaging where there is a usable temperature difference, tracer gas where there is not. For under-slab and underfloor heating leaks that typically means thermal imaging to identify the broad area, then tracer gas injected into the depressurised loop and detected at the slab surface, which is what allows a minimal-access repair rather than lifting a floor to look.

What has to be in the report — readings, photographs, dates, method

A report a loss adjuster can process, and a leaseholder cannot easily argue with, contains seven things. Most reports that fail are missing three or four of them.

Instruction and dates. Who instructed the survey, on what date, and the date of attendance. Where the insurer was notified before instruction, say so and give the date. Costs incurred before notification are the ones most often disputed.

Property and scope. The address including the flat number, what was inspected, and what was not — including anything that could not be accessed and why. An honest access limitation strengthens a report; an unstated one undermines it later.

Method, in sequence. Each technique used, in the order used, with the reason for moving from one to the next. This is the part that turns a conclusion into a finding. A report that lists equipment without saying what each instrument was used to establish is a specification, not evidence.

Readings with units and times. Meter readings with the interval between them. Heating system pressure before and after isolation. Moisture readings by location, stated as the instrument reports them and identified as surface or depth. Temperature differentials from thermal imaging. Numbers with units and timestamps are what distinguishes a survey from an opinion.

Photographs, referenced. Timestamped, and cross-referenced to the text and to a location plan or sketch. A folder of images at the back of a document is not evidence of anything in particular.

The finding itself. Origin stated as a location, cause stated as a mechanism, and the confidence attached to each. Where the cause cannot be established without opening up, say that rather than guessing — a report that says "origin confirmed at the compression joint beneath the bath; cause not determinable without exposure" is more useful than one that speculates.

Recommendation and separation of costs. What repair is required, what access is needed to carry it out, and what reinstatement follows. Detection, repair and making good should be identifiable as separate items. Trace and access cover is intended to pay for finding the leak and for the damage caused by opening up and putting back — typically capped somewhere between £5,000 and £10,000 depending on the policy — and generally not for the failed pipe itself. A single undifferentiated figure invites the adjuster to query all of it.

Section 11 and the landlord's repairing obligation

Section 11 of the Landlord and Tenant Act 1985 implies into most residential tenancies of under seven years a landlord's obligation to keep in repair the structure and exterior, and to keep in repair and proper working order the installations for the supply of water, gas, electricity and sanitation, and for space and water heating. The obligation is triggered by notice of the disrepair, and the landlord then has a reasonable time to put it right — reasonable being measured against the severity, not against a fixed number of days.

Two points matter for reporting. First, the obligation reaches installations, not just structure, so a leaking pipe serving the demised flat is squarely inside it. Second, the section extends in certain circumstances to installations elsewhere in the building that the landlord owns or controls and whose failure affects the tenant's enjoyment of the dwelling. In a block that is exactly the communal riser question, and it is why the finding of origin does real legal work rather than just settling an insurance line item.

A dated report also fixes the notice point. Where a tenant reported damp in March and the survey in June establishes a pipe failure rather than condensation, the report is the document that shows what was known and when. That cuts both ways, which is a reason to commission it early rather than a reason to avoid it.

Leaks between flats: freeholder, leaseholder, and the clause that decides

Water coming through a ceiling from the flat above is the most common leak dispute in London, and it is not resolved by fault. It is resolved by reading the lease.

Most residential leases divide the building into the demised premises — broadly the inside of each flat, with the boundary defined by the lease — and the retained parts, which the freeholder holds and insures. Pipework that serves only one flat and sits within its demise is usually the leaseholder's; pipework in a riser, in the structure, or serving more than one flat is usually the freeholder's. Where the line falls is a question about the specific lease wording, not a general rule, and the plane of the ceiling and floor slab between two flats is where the drafting is most often ambiguous.

The block buildings policy normally covers the whole structure and frequently includes trace and access. That is why the practical sequence is: notify the managing agent in writing immediately, ask whether the block policy's trace and access extension will fund the survey, and only then instruct. An independent report establishing origin is worth far more in a flat dispute than a plumber's verbal opinion, because the leaseholder above is entitled to disagree with an opinion and will.

Negligence is a separate question again. A leaseholder is not automatically liable for damage from a pipe inside their flat simply because it was inside their flat — liability generally requires negligence or a breach of a lease covenant. A report that establishes cause is what turns that abstract question into an answerable one, which is another reason it belongs in the file before anyone starts arguing about money.

Turnaround, and getting a report you can use the first time

The report is the deliverable. Ask to see a sample before you instruct, and read it as an adjuster would: can you tell what was measured, when, with what, and what was ruled out? If the sample would not survive that reading, neither will yours.

Three practical requests are worth making at the point of booking. Ask for the eliminations to be stated explicitly, not just the finding — most reports omit them and they are what makes the conclusion defensible. Ask for detection, repair and reinstatement to be costed as separate lines. And ask for a location plan or sketch that the photographs reference, because a document an adjuster can navigate is a document that gets processed rather than queried.

For managing agents handling several buildings, the format matters more than the individual finding. A consistent report structure across a portfolio means the same evidence lands the same way with every insurer, and it means an agent can answer a leaseholder's question by pointing at a page rather than re-litigating the survey. That is the whole point of writing it down properly.