AIRCON LEAKING WATER? FAST DIAGNOSIS AND SAME-DAY REPAIR

Why Is Your Aircon Dripping Water?

Finding a puddle of water beneath your aircon is never pleasant. In Singapore, where most HDB flats and condos run their aircon daily, water leaking is one of the most frequent aircon problems we encounter at Coolbest Aircon. With over 18 years of experience since 2005, our team has diagnosed and repaired thousands of aircon leaks island-wide. The good news is that in most cases, the cause is straightforward and fixable.

Your aircon naturally produces water as part of its cooling process. When warm, humid indoor air passes over the cold evaporator coil, moisture condenses on the coil surface - similar to how water droplets form on a cold glass. This condensation collects in a drainage tray beneath the coil and flows out through a condensate pipe to a drain point.

When any part of this drainage process is disrupted, water has nowhere to go except onto your wall, floor, or ceiling. Let us walk through the most common causes and how we fix each one.

6 Common Causes of AC Water Drip

1. Clogged Condensate Drainage Pipe

This is the number one cause of aircon water leaks, accounting for roughly 60-70% of the cases we see. Over months of use, the condensate pipe gradually accumulates a slimy buildup of dust, algae, and bacterial growth. Singapore’s high humidity makes this worse, as the warm, moist environment inside the pipe is ideal for biological growth.

When the pipe becomes partially or fully blocked, water backs up in the drainage tray and eventually overflows. You might notice the leak starting as occasional drips and gradually getting worse.

How we fix it: We flush the entire drainage system with pressurised water and cleaning solution to clear all blockages. We also clean the drainage tray to remove the slime buildup that feeds future clogs.

Prevention: Regular servicing - either a chemical wash every 6 months or a chemical overhaul annually - includes drainage system flushing that prevents clogs from forming.

2. Dirty Evaporator Coil

When the evaporator coil becomes coated with dirt and grime, it does not cool evenly. Some areas may become extremely cold while others remain warm, leading to irregular condensation patterns. In severe cases, sections of the coil can freeze, forming ice that eventually melts and produces more water than the drainage tray can handle.

A dirty coil also reduces airflow across its surface, which compounds the problem. Less airflow means the coil gets colder than it should, increasing the risk of ice formation.

How we fix it: A thorough chemical wash cleans the evaporator coil and restores even heat exchange. For severely contaminated coils, a chemical overhaul provides a deeper clean by removing and soaking the coil.

3. Low Refrigerant (Gas Leak)

When your aircon system loses refrigerant gas, the evaporator coil temperature drops abnormally low, causing excessive ice formation on the coil. When the compressor cycles off or when the ice buildup becomes too thick, it melts rapidly, producing a rush of water that overwhelms the drainage system.

You can sometimes spot this by looking at the outdoor unit - if you see ice on the copper pipes, low gas is likely the culprit.

How we fix it: We first perform a gas top-up to restore proper refrigerant levels, whether your system uses R410A or the newer R32 refrigerant. Importantly, we also check for the source of the gas leak, because topping up without fixing the leak means the problem will return.

4. Incorrect Unit Mounting Angle

Your aircon indoor unit must be mounted with a very slight tilt towards the drainage pipe side. This ensures water flows naturally from the drainage tray into the pipe. If the unit is even slightly tilted in the wrong direction - due to loose mounting brackets, wall settlement, or poor initial installation - water pools on the wrong side and drips out the front or sides. This is common in older HDB flats and condominiums where walls shift over time.

How we fix it: We adjust the mounting brackets and levelling to restore the correct drainage angle. We then test by pouring water into the tray to confirm it flows properly.

5. Damaged or Disconnected Drainage Pipe

Physical damage to the condensate pipe - cracks, kinks, or disconnections at joints - can cause water to leak before it reaches the drain point. This is sometimes caused by renovation work, accidental bumps, or deterioration of old piping.

How we fix it: We inspect the entire drainage route and repair or replace damaged sections. We use quality fittings to ensure a secure, leak-free connection.

6. Insufficient Pipe Insulation

The copper pipes connecting your indoor and outdoor units carry cold refrigerant. If the insulation around these pipes degrades, condensation forms on the pipe surface - similar to the outside of a cold drink can. This condensation drips down and can mimic a leak from the indoor unit.

How we fix it: We replace the damaged insulation with new foam insulation, covering the full length of exposed pipe. This stops condensation from forming on the pipe surface.

How We Diagnose the Leak

When our technician arrives, here is the systematic process we follow:

Visual Inspection. We look at where exactly the water is dripping from. The location of the drip tells us a lot - water from the front usually indicates a tilt issue, water from the side often points to a drainage problem, and water from the pipe area suggests an insulation issue.

Filter and Component Check. We open the front panel and inspect the filters, evaporator coil, and drainage tray for visible dirt, mould, or ice formation.

Drainage Flow Test. We pour a small amount of water into the drainage tray and watch how it flows. If it backs up or drains slowly, we know the condensate pipe is partially blocked.

Gas Pressure Check. If we suspect a refrigerant issue (indicated by ice formation or poor cooling), we check the gas pressure at the outdoor unit.

Mounting Level Check. We verify the unit’s mounting angle to ensure proper drainage gradient.

Our technicians are experienced with all major brands including Daikin, Mitsubishi, Panasonic, and LG, so we know the common leak points for each model. Based on our findings, we explain the cause to you clearly and provide a quotation for the repair before proceeding.

How to Prevent Future AC Leaks

Once we have fixed your water leak, here is how to keep it from happening again:

Schedule Regular Servicing

The single best way to prevent water leaks is regular professional servicing. A chemical wash every 6 months keeps the drainage system clear and the evaporator coil clean. For older units or heavily used systems, a chemical overhaul once a year provides an even more thorough cleaning.

Clean Your Filters Fortnightly

Dirty filters restrict airflow and cause the evaporator coil to get too cold, leading to ice formation and excessive condensation. Rinse your filters under running water every two weeks and let them dry completely before reinstalling.

Do Not Set Temperature Too Low

Setting your aircon to 16°C or 18°C does not cool the room faster - it just makes the evaporator coil run extremely cold, increasing the risk of ice formation and water issues. The National Environment Agency (NEA) recommends 25°C for energy efficiency, and this temperature range also reduces strain on your system.

Keep an Eye on the Drainage Outlet

If your condensate pipe drains to an external point, check occasionally that the outlet is not blocked by debris, dirt, or insect nests.

Address Issues Promptly

If you notice even a small drip, do not wait for it to become a major leak. A small drainage issue that costs S$50 to fix today can cause hundreds of dollars in water damage to your flooring and furniture if left unaddressed.

How Much Does Aircon Leak Repair Cost in Singapore?

Service	Price
Drainage pipe clearing and flushing	From S$50 (2026)
Drainage tray cleaning and realignment	From S$60
Unit mounting angle correction	From S$80
Pipe insulation replacement	From S$50
Chemical wash (preventive + repair)	From S$80/unit

In many cases, a chemical wash is the most cost-effective solution because it addresses drainage blockage, dirty coils, and contamination all at once. If the water leak is caused by low gas, a separate gas top-up may be needed. Full aircon pipe replacement is a separate service that typically costs more - contact us for a quote based on your system size and installation type.

How Does Coolbest Compare?

Feature	Typical Provider	Coolbest Aircon
Diagnostic approach	Visual check only	5-step systematic diagnosis including drainage flow test and gas pressure check
Warranty	None or 30 days	90-day workmanship warranty
Pricing transparency	Quote after work starts	Upfront quote before any repair
Brand expertise	Limited brands	Daikin, Mitsubishi, Panasonic, LG, Toshiba - all major brands
Response time	2-3 business days	Same-day service available

When a Drip Signals a Bigger Problem

While most water leaks are straightforward to fix, occasionally a leak can indicate a more serious issue:

• Persistent ice formation despite clean coils may indicate a failing expansion valve or compressor issue
• Water leaking from the outdoor unit excessively can point to a refrigerant system problem
• Leaking that persists after multiple repairs may suggest the drainage tray itself is cracked or warped

If we find any of these more complex issues during our diagnosis, we will explain the situation honestly and help you weigh up whether repair or replacement makes more economic sense for your specific unit.

Related Aircon Problems Worth Checking

Water leaking often occurs alongside other aircon problems. If your aircon is also:

• Not blowing cold air - check our aircon not cold troubleshooting guide for possible causes
• Making unusual noises - see our noisy aircon diagnosis page
• Producing a bad smell - read about our smelly aircon solutions

These symptoms can share common causes with water leaks, and addressing them together during a single service visit is more efficient and cost-effective.

Book Your Leak Repair Today

Do not let a water leak damage your home. Contact Coolbest Aircon at 9182 5233 or email hello@coolbestaircon.com for same-day diagnosis and repair. Based in Jurong West, we serve homeowners across Clementi, Bukit Batok, Toa Payoh, Tiong Bahru, and all areas of Singapore.

With over 18 years of experience fixing aircon water leaks in HDB flats, condos, and landed homes across Singapore, we have seen every possible cause and know exactly how to resolve each one. Our work is backed by a 90-day workmanship warranty, and we always explain the problem and quote the price before starting any repair.