Why is My Aircon Leaking Water?

Water leaking from a commercial air conditioning system is often first noticed as a minor inconvenience. A small puddle beneath an indoor unit. Drips appearing through ceiling tiles. Damp patches forming where they shouldn’t.

In commercial buildings, these signs tend to appear without warning and usually indicate that part of the system isn’t managing moisture as it should.

If you’re asking, ‘Why is my aircon leaking water?’, it’s a common question in commercial environments. While the water itself may seem harmless, it typically points to an underlying issue that needs attention to avoid disruption to your building or operations.

Understanding what causes these leaks makes it easier to act early and keep systems running reliably.

Why Water Leaks Are Common in Commercial Air Conditioning Systems

All air conditioning systems remove moisture from the air as part of normal operation. In commercial settings, this process happens on a much larger scale.

As warm air moves across the evaporator coil, condensation forms and drains into a collection pan before flowing out through a condensate drain line. When that drainage process is interrupted, water can accumulate and escape into surrounding areas.

Commercial air conditioning systems are more susceptible to this because they typically:

• Operate for extended hours, often continuously
• Manage higher airflow and cooling loads
• Serve multiple zones and large floor areas
• Rely on complex ducting and drainage layouts
• Function in environments with higher humidity or airborne particles

When facility or operations managers ask, ‘Why is my aircon leaking water?’ the answer is usually linked to system load, airflow restrictions, or drainage issues rather than a single isolated fault.

Common Causes of Aircon Water Leaks in Commercial Buildings

Blocked or Compromised Condensate Drain Lines

Blocked drain lines are one of the most frequent causes of water leaks in commercial air conditioning systems.

Over time, condensate drains can collect:

• Dust and airborne debris
• Mould or algae growth
• Residue from constant moisture exposure

When a drain line becomes restricted, water backs up into the drain pan. Once the pan reaches capacity, excess water can overflow into ceilings, walls, or floor areas, sometimes well away from the unit itself.

In buildings with multiple indoor units, a single blocked drain can affect several spaces at once.

Dirty or Clogged Air Filters

Air filters play a key role in maintaining consistent airflow across the evaporator coil.

When filters are not cleaned or replaced regularly:

• Airflow is reduced
• The coil temperature drops too low
• Ice can begin to form on the coil surface

As that ice melts, it releases a sudden volume of water. If the drainage system cannot manage the increase, leaks can occur.

This is commonly seen in offices, warehouses, gyms, and hospitality venues where systems operate daily and maintenance intervals are extended.

Frozen Evaporator Coils

Frozen coils are another common contributor to unexpected water leaks.

Freezing may occur due to:

• Restricted airflow
• Refrigerant-related performance issues
• Extended operation under heavy demand

While the coil remains frozen, there may be no visible water at all. The issue typically becomes apparent when the system cycles off and the ice thaws, releasing more water than the drain system can immediately handle. This is why leaks often appear after hours or overnight.

For many businesses, this explains why an air conditioner that appeared to be running normally suddenly begins leaking water, and why the question ‘Why is my aircon leaking water?’ often comes up without warning.

Incorrect Installation or Unit Levelling

Commercial indoor units must be installed and levelled accurately to allow condensate to drain correctly.

If a unit is even slightly out of level:

• Water may collect in the wrong section of the drain pan
• Condensate may not reach the drain outlet efficiently
• Leaks can occur despite clear drain lines

This is more likely in older buildings, retrofit installations, or sites where equipment has shifted over time.

High Humidity and Heavy Usage Environments

Some commercial environments place additional strain on air conditioning systems.

Warehouses, production facilities, gyms, commercial kitchens, and buildings with frequent door openings generate higher levels of moisture. In these conditions, condensate volumes can exceed what the system was originally designed to manage.

If the system has not been maintained or adapted to suit these demands, water leaks become more likely over time.

Why a Leaking Air Conditioner Should Never Be Ignored

In commercial environments, there is a clear line between basic observation and professional intervention.

It may be reasonable to:

• Identify where water is pooling
• Note whether icing has recently occurred

However, any work involving condensate drainage, refrigerant systems, electrical components, or ceiling-mounted units should be handled by licensed technicians.

Commercial air conditioning systems operate under strict safety and compliance requirements. Proper diagnosis ensures issues are resolved correctly and safely.

How Preventive Maintenance Helps Stop Aircon Water Leaks

Regular commercial air conditioning maintenance plays a key role in preventing leaks.

During scheduled servicing, technicians can:

• Clear and flush condensate drains
• Inspect drain pans and pipework
• Clean coils and service air filters
• Check airflow balance and system performance
• Identify early signs of freezing or overload

For facility and operations managers, this results in fewer unexpected issues, improved reliability, and reduced disruption to daily operations.

In many cases, leaks are avoidable when systems receive the maintenance they require.

When to Call a Commercial Air Conditioning Specialist

If you’re still asking, ‘Why is my aircon leaking water after basic checks?’, professional assessment is recommended when:

• Leaks continue to return
• Water is entering ceilings, walls, or electrical areas
• Multiple indoor units are affected
• The system shuts down or struggles to maintain temperature
• The cause is not immediately clear, or access is restricted

In commercial environments, water leaks rarely resolve without intervention. Early involvement helps protect equipment, maintain safety, and keep operations running smoothly.

Fix a Leaking Commercial Air Conditioner Before It Becomes a Bigger Issue

Water leaks are a clear sign your air conditioning system needs attention. Left unresolved, they can lead to damage, downtime, and costly repairs.

At Perth Air & Power Solutions, we specialise in diagnosing and resolving commercial air conditioning issues quickly and correctly. From urgent repairs to preventative maintenance, our qualified technicians deliver reliable solutions that keep your systems running as they should.

Contact our team today to arrange professional commercial air conditioning support across Perth.

Frequently Asked Questions