Flat Leaked After Servicing: Drain Hose Reseated Wrong

A flat starts leaking days after a service. What follows works out whether the pipework failed or the reconnection did.

By Team Snowflake | Updated 24 Aug 2026

How this presents

Water escaping at a unit only days after a service, with the drain hose firmly attached at both ends. The line beyond it is clear. Water shows at the connection rather than further down the run.

Setup: Mitsubishi Electric Wall-mounted4-6 yearsHDBAng Mo Kio
Misread as: Pipework that has failed on its own, needing the run opened up behind the trunking to reach.
Check first: The angle the hose leaves the unit at, rather than whether it is attached

What else produces this

A hose that is firmly attached and still lets water out has been put back in the wrong position rather than left off. Condensate leaves the unit at a particular point and has to be led away downward from there. A hose seated at an angle that lifts even slightly holds water at the connection and lets it find the gap. Looking at the angle the hose leaves at, rather than checking that it is on, is what shows this.

A hose firmly attached at both ends rules out anything having simply been left disconnected.
A clear line beyond the connection removes any obstruction downstream from the picture.
Water escaping at the connection rather than further along places the fault right there.
A hose seated at an angle that rises slightly holds water at exactly that point.

Why it happens

A drain hose has one correct orientation, and it is set by where the water needs to go rather than by where the hose will reach. Refitted quickly it can seat firmly while pointing a few degrees the wrong way. Water then collects at the connection instead of running away from it, and once enough gathers it escapes at the joint. The connection is sound and the geometry is not.

What resolution involves

Reseating the hose at the correct angle sends water away from the unit downward from the first moment. What separates this from a leak is worth stating: nothing has failed, nothing needs replacing, and the fix is a repositioning. Checking the angle at reassembly costs one glance, and it is not part of most people's routine.

How to tell it worked

Water sent down the pipe with the trunking still off, watching the connection itself rather than the far end. A hose at the wrong angle passes water eventually, and weeps at the joint while it does so.

Before you approve a quote

Firmly attached is not the same as correctly aimed

A hose can be tight and still point the wrong way. Secure says nothing about direction.
Water has to leave the unit downward from the first moment. Any rise holds it at the connection.
Check the angle at reassembly, not just that the hose is on. It costs one glance.

Questions this case answers

Why did my aircon start leaking a few days after servicing?

Because attachment and orientation are different things. A hose can seat firmly while pointing a few degrees the wrong way, and nothing about how tightly it is held tells you which way it is aimed.

What causes a slow drip near the aircon trunking?

Water collects at the connection rather than running away from it. Once enough gathers, it finds the joint and escapes there, which is why the water shows at the unit and not further along the run.

Aircon leaking after service: does the drain hose need replacing?

Look at the angle it leaves the unit, and confirm the hose falls away from the first moment. Any section that rises, even slightly, will hold water at that point rather than carrying it onward.

What should be asked before paying for drainage work after a service?

Nothing at all. The hose is sound and the line beyond it is clear, so the work is repositioning rather than replacing. It is one of the cheapest post-service faults to put right once it is understood.

Ready to get started?

Tell us what’s going on. Symptoms, setup, photos, anything we should know. We’ll assess and come back with the right next step.

WhatsApp us