Who is liable when an aircon leak damages your home

An aircon leak that stains a ceiling or damages a floor raises a question that isn’t always simple to answer: whose fault was it, and who pays to fix it? This is general information, not legal advice, but here’s how responsibility typically gets worked out.

The three usual causes, and who they point to

Installation defect. A slope error in the drain pipe, poor sealing, or a badly mounted unit can cause leaks from day one or soon after. If this is the cause, the installer is often liable under the installation warranty, this is exactly why keeping your installation paperwork matters.

Normal wear, not maintained. A blocked condensate drain or a degraded seal that builds up over years of use is a maintenance issue. Who’s liable here often comes down to whose job servicing was, the homeowner’s, or a tenant’s under a lease.

Sudden or accidental damage. A leak from a specific event, storm damage, an accidental knock to the unit, tends to be treated differently again, and may fall to home insurance rather than either party’s ongoing responsibility.

Cause	Who’s typically responsible
Installation defect (early leak)	Installer, usually under warranty
Blocked drain from lack of servicing	Whoever held the servicing obligation
Ageing part failing despite servicing	Often the owner or landlord
Sudden accidental damage	Often a home insurance matter
Neighbour’s unit damaged by your leak	Depends on cause, get specific advice

Why documentation matters more than memory

If a dispute comes up, whoever can show records, an installation invoice, servicing receipts, warranty paperwork, is in a far stronger position than whoever is relying on “I think it was serviced.” Keep this paperwork somewhere you can find it, not just in an old text message thread with a contractor.

What to do when a leak causes damage

Photograph the damage and the source of the leak before any repair work starts, this record is useful regardless of who ends up liable. Get a technician to diagnose the cause, not just fix the symptom, the diagnosis is often what determines liability. If you’re a tenant, notify your landlord promptly, delaying notification can complicate a claim later.

Where insurance fits in

Many home contents or renovation insurance policies do cover water damage from a leaking aircon, but the details vary significantly by insurer and policy. Check your specific coverage rather than assuming it’s included, and note that most policies distinguish between sudden accidental damage and damage from prolonged neglect.

When to get real advice

If a leak has caused significant damage, involves a landlord-tenant disagreement, or affects a neighbour, this is worth a conversation with someone qualified to advise on your specific situation rather than relying on general guidance. What’s outlined here is a starting point for understanding the usual pattern, not a substitute for that.

Preventing the next leak

Most aircon leaks trace back to one of two causes: a blocked or poorly sloped condensate drain, or a coil that’s built up enough dirt to affect drainage. Both are largely preventable with servicing on a reasonable schedule, which is also why a documented maintenance history matters twice over, it reduces the chance of a leak happening at all, and it strengthens your position if one does occur despite reasonable care.

A short summary for landlords and tenants alike

Whoever holds the servicing responsibility under a lease effectively holds a share of the liability risk too, since a leak from neglect points back to whoever should have been maintaining the unit. Treating servicing as a shared interest, not just a box to tick, benefits everyone involved when something eventually goes wrong.

For contractors who can diagnose the cause of a leak properly, see our methodology page for how we assess listings, or the homepage for the full directory.