General Assist Customer Support

Why Does My Outdoor Unit Leak Water in Cooling Mode?

Understanding normal condensation and when water may indicate a problem
In most cases, a small amount of water around the outdoor unit during cooling operation is normal. It is usually condensation from cold refrigerant pipework or water discharged from the indoor unit's drain pipe nearby.

Why water may appear near the outdoor unit

1. Condensation on refrigerant pipes and valves

While the air conditioner is cooling, the larger refrigerant pipe returning to the outdoor unit can become cold. In warm or humid weather, moisture in the surrounding air may condense on this pipe, its insulation, or the service valves.

The resulting droplets can run down the casing, mounting bracket, or wall and collect beneath the outdoor unit. This may look like a leak, but a small amount of clear water is generally normal.

2. The indoor drain pipe may discharge nearby

In cooling mode, the indoor unit removes moisture from the room air. This water flows through a drain pipe, which is often routed to an area close to the outdoor unit.

Water seen beneath the outdoor unit may therefore be coming from the indoor drain outlet rather than from the outdoor unit itself. The amount of water can increase on hot, humid days.

3. Rainwater, dew, or external runoff

Rain, morning dew, roof runoff, irrigation, or water from an overhead structure can collect on the outdoor unit and drain away later. This can continue for some time after the external moisture source has stopped.

Important: The outdoor heat-exchanger coil normally becomes warm or hot during cooling operation. Water is therefore not generally produced by condensation on the outdoor coil itself while the system is cooling.

What you can check

ObservationLikely explanation
Clear water or occasional drippingNormal condensation or nearby drain discharge
More water on humid daysHigher humidity produces more condensation indoors and on cold pipework
Water appears after rainRainwater or external runoff draining from the casing
Water is coming from a small pipe beside the unitNormal discharge from the indoor unit's condensate drain

Water dripping onto concrete can leave temporary marks or mineral staining. These marks are normally cosmetic and do not indicate a refrigerant leak.

When should I arrange an inspection?

Contact a licensed air-conditioning technician if you notice any of the following:

  • The liquid has a greasy or oily appearance.
  • Water is entering the building or causing significant flooding.
  • Refrigerant pipe insulation is damaged, missing, or saturated.
  • The air conditioner is not cooling correctly.
  • The unit displays an error code or makes unusual noises.
  • There is ice forming on the refrigerant pipes or indoor unit.
Do not open or dismantle the outdoor unit. Air-conditioning equipment contains electrical components and pressurised refrigerant and should only be inspected internally by appropriately qualified personnel.

Installation considerations

Outdoor units and drain outlets should be positioned so that normal water discharge does not create a slip hazard, stain sensitive surfaces, or affect neighbouring properties.

  • Keep the area around and beneath the outdoor unit clear.
  • Ensure the indoor condensate drain terminates in a suitable location.
  • Do not block drain openings or attempt to seal the base of the outdoor unit.
  • Ask the installer about drainage options if water is affecting a pathway or landscaped area.
Summary
A small amount of clear water near an outdoor unit during cooling is usually normal. It commonly comes from condensation on cold refrigerant pipework, the indoor unit's drain outlet, or external moisture such as rain. Arrange an inspection if the water is oily, excessive, entering the building, or accompanied by poor performance, ice, unusual noise, or an error code.