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Why is my air conditioner leaking water?

Why is my air conditioner leaking water?


Whether heating or cooling, moisture in the air will condense on cold components of your air-conditioner. It is a normal part of the process.

It’s like a glass of cold beer on a hot summer’s day. As it sits on the table, moisture in the warm air condenses on the outside of the glass, and runs down to the absorbent coaster underneath.

All of this is fine.

Problems can arise however, when the condensed moisture collects in your air-conditioner and doesn’t drain away properly. It can then cause issues with the interior or the exterior of your home, depending on the situation.

As we explore in the following article, a leaking air conditioner is only a problem depending on WHERE the water is leaking from. 

Water is leaking from the drain pipe connected to the outside unit

If you’re operating your air con on cooling mode and notice a small amount of water leaking off the PVC drain pipe connected to the outdoor unit, don’t panic. This is completely normal.

As air moves across the evaporator coil of your inside unit, the coil absorbs heat and also condenses moisture from the air onto the coil. The water you are seeing is being caused by a build up of condensation on parts of the inside unit which have become cold.

The majority of the water caused by the condensation will drain away out of the inside unit and down the drain pipe. You may notice a small puddle on the ground from time to time which will eventually dry up on a hot day.

However, if you notice persistent dripping even when the air conditioner isn’t turned on, then this is likely a sign of a problem and needs to be checked out by an air conditioner professional.

It may be a case of a blockage in the drain pipe, causing water to build up inside the unit, instead of flowing away freely to the drain.

Whatever the cause, having your air-conditioner serviced is important, as it can be a case of “a stitch in time saves nine”. If water isn’t running to the drain, it will be going somewhere — and that could be in your ceiling or walls — bringing with it the potential for expensive repairs to gyprock, carpets or other parts of your house.

QUICK TIP –  From time to time, check that your drains aren’t blocked with leaves, dirt or other debris so that any condensation coming from the pipes can easily flow away.

Water is leaking from the bottom of the outside unit

This can occur in winter when you’re using your air conditioner on heating mode. Again, this no immediate cause for alarm. 

When you’re running your air conditioner on heat mode, the indoor unit is blowing warm air throughout your home and raising the inside temperature.

In winter the indoor unit becomes a condenser instead of the outdoor unit blowing out hot air. The indoor unit now blows hot air and the outdoor unit blows the cold air. This is the reverse to what happens in summer.

While this is happening, your outdoor unit will start to cool down due to the low outside temperature.

This starts the process of condensation and water pulled from the air will run down the outdoor coil and pool at the bottom of the unit.

Most air cons don’t have a drain connected at the bottom of the outdoor unit, so the water will just drip onto the ground and pool around the unit.

While this is completely normal, having a puddle of water around the outside unit may look bad or become a slipping hazard if the unit is in a high visibility area such as on a patio/deck.

To solve the problem, special drain kits can be installed in such cases which will drain away water from the bottom of the outside unit.   

Water is leaking from the inside unit

If you’ve got water coming out the front or the sides of your inside unit onto the wall of your home – this is not OK and you should call a professional air conditioning contractor ASAP.

Some of the most common reasons an air conditioner will leak water inside include:

  • Condensate drain line clogged
  • Drain line disconnected
  • Drain pan clogged or rusted through
  • Condensate pump malfunctioning
  • Evaporator coil frozen (due to a clogged filter or refrigerant leak)
  • Coils dirty or damaged
  • Improper installation

A professional air conditioning contractor will be able to diagnose the source of the problem and may recommend a major service to fix the issue. This can include:

  • Dissembling the inside and external unit
  • Chemically cleaning all components to prevent mould
  • Checking the drains
  • Reassembling
  • Test running the units
  • Reporting on the condition of your unit and the cause of the fault
  • Discuss with you any further work that may be required

Not sure if the water coming from your air con is a problem or not? Just ask Acer Services!

For help and advice, talk to one of our friendly, helpful team members. We can arrange one of our expert technicians to inspect your unit and let you know if any servicing or repair work is required.

Simply click here to get in touch.