Water Dripping onto Parquet: Algae Blocking the Drain Tray

Water reaches parquet flooring and a cracked tray is proposed. Whether the tray has failed or is simply unable to empty.

By Team Snowflake | Updated 24 Aug 2026

Teaching case based on recurring Snowflake service patterns; identifying details are combined.

How this presents

Water dripping from the front of the unit onto parquet flooring in a bedroom, worsening, with towels underneath no longer keeping up. Cooling is normal. The floor below is the more expensive problem than the aircon.

Setup: Samsung Wall-mounted7-9 yearsHDBNovena
Misread as: A cracked tray, major disassembly, and parquet flooring in the firing line.
Check first: Which side of the unit the drip comes from, before anything is opened

What else produces this

A tray sheds water two ways. Through it, if the tray itself has failed, and that water runs down the back where the pipework sits. Over it, if the outlet cannot take the flow, and that water finds the front lip because the front is the low, open edge. The drip location is therefore the first branch, and it is free.

A drip at the front of the unit rather than behind it points at overflow, not at a breach.
A thick green layer across the tray surface, sitting over the outlet, seals the exit rather than the tray.
Water pooling in the tray with no path out matches the front-edge drip exactly.
A tray with no cracks, holes or corrosion once cleaned confirms the structure was never the fault, only the exit from it.

Why it happens

Algae and biofilm grow wherever water sits and light reaches, and a drain tray offers both for hours every night. The layer thickens over years until it creeps across the outlet and seals it. Water then has nowhere to go but up, and the front lip is the lowest open edge of the tray, so that is where it goes. The tray underneath stays perfectly sound the whole time.

What resolution involves

Clean the tray, clear the outlet, and flush the line to confirm flow before closing up. No parts are needed and nothing comes off the mounting. Where flooring below is at risk, add a tray check to each service rather than waiting for the next drip. This fault gives months of warning and produces no symptom until the moment it produces a puddle.

How to tell it worked

Water leaving through the outlet, not merely a tray that looks clean. A cleaned tray with a partly cleared outlet drains slowly and overflows again on the first heavy night.

Before you approve a quote

Where the water falls tells you which fault it is

Look at which side the drip comes from before anything is opened. Front is overflow; back is a breach.
A sealed outlet and a cracked tray produce completely different puddles in different places.
Where flooring is at risk, a tray check at each service is cheaper than the first repair to the floor.

Questions this case answers

Water dripping from the front of a wall aircon onto the floor: what does that mean?

Overflow rather than a leak. A tray that has failed sheds water through itself and down the back, where the pipework runs. Water coming over the front lip means the tray is holding water it cannot drain, and the front is simply the lowest open edge it can reach.

Can algae really block an aircon drain?

Routinely, and it is among the commonest causes. A tray stays wet for hours every night, which is all algae needs. The layer thickens across years until it creeps over the outlet and seals it, at which point the tray fills instead of draining.

How do I know the tray is blocked and not cracked?

By where the water appears and by what the tray looks like once opened. A blockage leaves a clean, intact tray full of water with a covered outlet. A crack leaves a tray that empties normally and wets the wall behind the unit.

Will a dripping aircon damage parquet flooring?

It can, and quickly, which is why this is worth acting on at the first drip rather than the third. Parquet swells from below and the damage is usually more expensive than anything the aircon needed. Towels buy time; they do not stop the source.

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