Leak From an Upstairs Rented Flat — Do You Sue the Landlord or the Tenant?

Water starts coming through your ceiling, and tracing it up leads to the flat directly above — except that flat is rented out, and the registered owner doesn't live there. Many people's first move is to write to the owner, only to be told: "someone's renting it right now, that's not on me, go find the tenant."

This is a different problem from every other water-leakage scenario on this site. Our guide to a leak from a private owner-occupied unit above covers a dispute where the source unit's owner lives there; our case note on a three-year ceiling leak covers a tenant's claim against their own landlord. What this article covers is different again: you have no tenancy relationship with either the owner or the tenant upstairs — you're a third-party neighbour who has to work out, from scratch, who to actually pursue.

Why Is a Leak From a Rented Upstairs Flat Extra Difficult?

When an upstairs owner lives in their own flat, the source and the responsible party are usually the same person. Once that flat is rented out, the picture splits in two: the owner isn't there to notice a problem first-hand, and the tenant living there day-to-day has no contractual relationship with you at all — whether they respond to you is genuinely uncertain.

This "the owner doesn't know, the tenant won't engage" standoff leaves a lot of affected neighbours stuck before they've even worked out who to write to.

Liability Follows Who Knew and Didn't Act — Not Who Owns the Flat

Under Hong Kong law, civil liability for a nuisance like water leakage doesn't automatically follow ownership or which floor someone lives on — it follows whoever had knowledge of the leak's source (actual knowledge, or what they ought reasonably to have known) and failed to take remedial action within a reasonable time. The Community Legal Information Centre (CLIC), through Family CLIC, sets this out clearly: a claimant must show the leak originates from the defendant's premises, and that the defendant had actual or constructive knowledge of the leak but failed to remedy it within reasonable time — a defendant generally isn't liable for losses that occurred before they had that knowledge, provided they act once informed.

Applying that principle, working out whether the owner or the tenant should answer for it generally looks like this:

Situation	Who's generally liable
The source is ageing pipework or a structural waterproofing failure in the upstairs unit (the owner ought to know, the tenant is merely using the flat)	Usually the owner
The tenant's own negligence — an unattended tap, an unauthorised pipe alteration, or sitting on a known leak without telling the owner	Usually the tenant
Both owner and tenant knew and simply kept deflecting each other for months	Either or both, depending on whose inaction actually let the loss continue

Centaline Surveyors' own guide to burst pipes in rented units makes the same point in practice — liability depends on the tenancy's own terms and on whether a professional inspection shows the cause was ageing infrastructure or a tenant-caused fault, not on a blanket rule. A separate Hong Kong legal guide on water leakage puts it more plainly still: responsibility isn't decided by floor position, but by the leak's source, the underlying property rights, and which party can actually be shown to carry legal responsibility for it — which can turn out to be the owner, the tenant, or both.

A Land Search Finds the Owner — It Won't Find the Tenant

Even once you understand the principle, a third-party neighbour hits a very practical wall: you may not even know who currently lives in the source unit. A Land Registry search only returns the registered owner's information — it was never designed to reveal who a unit is rented to, because a tenant has no registered interest in the land record at all.

In practice, the safer approach is to address your written notice to both "the Owner" and "the Occupier" of the unit, or route it through the building's management office or Owners' Corporation so whoever is actually living there also receives it. This does double duty: it also builds the knowledge record you need — once you can show both the owner and the unit's occupier were notified, it becomes much harder for either to later claim they didn't know.

Can't Pin Down the Source? The Joint Office's New Procedure Can Help

Visual inspection alone often can't confirm the source, or whether the owner "ought to have known" about a structural issue. The safer route is reporting it to the Joint Office for Investigation of Water Seepage Complaints (call 1823 or submit online).

Under normal circumstances the Joint Office contacts the complainant within 6 working days of a report, then inspects the site and runs systematic non-destructive testing to identify the source. Since 16 July 2026, the Joint Office has added infrared thermal imaging analysis to its initial investigation, alongside the existing electronic moisture meters — for straightforward cases, it can now issue a Suggested Repair Notice to the suspected unit within roughly 14 working days, about 57 working days faster than the previous process. The owner then has 28 calendar days to self-inspect and complete repairs. If they don't comply, the Joint Office proceeds to a second and third phase of testing, can issue a Nuisance Abatement Notice, and recovers inspection fees (typically around HK$17,000) from the non-compliant owner.

Importantly, the Joint Office's role is to investigate and follow up on the nuisance — it does not decide who owes you compensation. Its findings, including which unit received a Suggested Repair Notice, can become important evidence for whatever civil claim you bring afterwards.

Evidence to Prepare Before You Pursue a Claim

Whether you end up pursuing the owner, the tenant, or both, having your evidence in order is what gives you leverage:

Evidence type	Recommended approach
Land Registry search record	Establishes the registered owner's identity as the recipient of your first notice
Written notice addressed to "the Owner/Occupier"	State the issue and your request clearly, and keep proof of postage — this becomes your evidence of when "knowledge" began
Joint Office findings / Suggested Repair Notice	Keep the original and a copy, especially any part identifying the suspected unit and source
An independent surveyor's or plumber's opinion	To help establish whether the cause is structural ageing or the occupant's own negligence
Photos/videos of the leak	Record continuously from the day it's discovered, with dates and times, showing how long the problem has persisted
Repair quotations (2–3)	Itemising materials and labour, to support your claimed amount

For how to turn this evidence into a hearing-ready bundle, see the Small Claims Tribunal evidence preparation guide; if you want to send a formal demand letter before filing, there's a template in the demand letter guide. Like our article on rooftop leak liability covers for a different three-way split, what an adjudicator ultimately weighs here isn't who tells the better story — it's the record you can produce showing the other side knew, or should have known, and didn't act.

Can't Tell Who to Pursue? Filing at the Small Claims Tribunal

If the owner and the tenant both keep stalling, and the loss (including losses already incurred and reasonably anticipated) is HK$75,000 or below, you can consider filing a claim at the Small Claims Tribunal.

Before filing, send a written demand letter to both the owner and the tenant, clearly stating the amount claimed and a deadline, and keep proof it was sent. If they keep ignoring you, you can go in person to the Tribunal registry to submit Forms 1 and 2 and pay the filing fee — fees are tiered by claim amount: HK$20 for claims up to HK$5,000; HK$40 for HK$5,001–$25,000; HK$70 for HK$25,001–$50,000; HK$120 for HK$50,001–$75,000 (fees are set by subsidiary legislation and may change — check the Judiciary's latest published schedule before filing).

Where the evidence clearly points to one party — for example, a Suggested Repair Notice that identifies a structural defect the owner should have fixed — name that party as defendant. Where the evidence suggests both the owner and the tenant may share responsibility, or you genuinely can't yet tell which of them caused it, you can name both as co-defendants and let the adjudicator weigh the evidence from both sides. If you'd like someone to walk through the search, the notices and the filing with you, see what our filing assistance service covers and how it's charged; if your situation matches a different water-leakage scenario, our water leakage case overview may be a more useful starting point.

Note that general civil claims for property damage must generally be brought within 6 years from the date the cause of action arose — so it pays to preserve evidence and act early. Even a successful judgment isn't automatically enforced — if the other side still doesn't follow through, you'll need to apply for a writ of execution yourself; see how to enforce a Small Claims Tribunal judgment for the details.