Aircon Leaking Water in Your HDB? Causes, Fixes & When to Call a Pro

QUICK ANSWER Aircon leaking water in your HDB is most commonly caused by a blocked drainage pipe, dirty evaporator coil, or cracked drain pan. Most leaks are fixed during a general service from $50/unit. Turn off your unit immediately to prevent water damage to your walls and flooring, then call a technician.

DID YOU KNOW? Blocked drainage pipes account for over 70% of aircon water leak calls in Singapore HDB flats. Water damage to walls and flooring from an untreated aircon leak can cost $500–$3,000 to repair — far more than a routine service. In HDB flats, a leaking aircon that drips to the unit below can result in a neighbour dispute or HDB complaint — making a fast fix essential.

There are few aircon problems more stressful than waking up to find water dripping from your unit onto your floor, bed, or furniture. In Singapore's HDB flats, aircon water leaks are one of the most common service calls we receive — especially during the humid months.

The good news is that most aircon leaks are fixable, and some can even be sorted out temporarily by yourself before a technician arrives. This guide walks you through the 5 most common causes of aircon water leaks in Singapore homes, what you can do right now, and when you need to call a professional.

Why Is My Aircon Leaking Water?

Before we dive into the causes, here's what's happening inside your aircon:

When your unit cools the air in your room, it also removes moisture from the air (that's why aircon doubles as a dehumidifier). This moisture collects as water droplets on the evaporator coil, drips into a drain pan, and flows out through a drainage pipe — usually leading to an external drain or the toilet.

When any part of this system gets blocked, dirty, or damaged, the water has nowhere to go — and ends up dripping inside your home instead.

5 Causes at a Glance

Cause	Most Common Sign	Urgency
Blocked drainage pipe	Steady drip from front of unit	High — turn off immediately
Dirty evaporator coil	Intermittent leak + weak cooling	High
Cracked drain pan	Random drip points, older unit	High
Improper installation	Leaking since day one	Medium
Low refrigerant / frozen pipes	Sudden heavy leak + no cold air	Critical — turn off now

Aircon water leaks in Singapore HDB flats are one of the most common — and most damaging — problems homeowners face. Turn off your unit immediately and call a technician. Coogle Aircon responds same-day or next-day across Singapore.

Cause 1 — Is a Blocked Drainage Pipe Causing My Aircon to Leak?

What's happening: Dust, mould, algae, and slime build up inside the drainage pipe over time, eventually blocking the flow of water. This is by far the most common cause of aircon leaks in HDB flats — we see it on almost every service call.

Signs to look for:

• Water dripping from the front of the indoor unit

• Water pooling directly below the unit

• The leak gets worse the longer the aircon runs

• You haven't serviced your aircon in 3+ months

Quick DIY check: Look at the external drainage pipe (usually running along your ledge or wall). If no water is dripping out while the aircon is running, the pipe is likely blocked.

Temporary fix: Switch off the aircon immediately to stop further leakage. Place a towel or container under the leak to catch water. Do NOT continue running the unit — this can damage your walls and flooring.

Professional fix: A technician will flush the drainage pipe using a pressurised vacuum or specialised tools to clear the blockage. This is usually included in a general service and takes 15–20 minutes to fix.

Blocked drainage pipes account for over 70% of aircon water leak calls in Singapore. A technician clears the blockage in 15–20 minutes during a general service from $50/unit.

Cause 2 — Could a Dirty Evaporator Coil Be Causing the Leak?

What's happening: When the evaporator coil is coated in dust and grime, it can't transfer heat properly. This causes ice to form on the coil, and when the ice melts, it overwhelms the drain pan and overflows inside your home.

Signs to look for:

• Water leaks in short bursts rather than a steady drip

• Reduced cooling performance alongside the leak

• Unit has not been deep-cleaned in over 6 months

• You can see dust or dirt on the coil when you open the front panel

Temporary fix: Switch off the aircon for a few hours to let any ice melt. Place towels to catch the water.

Professional fix: A chemical wash or steam cleaning will fully restore the coil. At Coogle Aircon, our steam-boost cleaning effectively removes stubborn buildup without harsh chemicals.

A dirty evaporator coil causes ice to form — and when it melts, it overwhelms the drain pan. A chemical wash or steam-boost cleaning fully restores the coil and stops the leak.

Cause 3 — Is a Cracked or Disconnected Drain Pan the Problem?

What's happening: The drain pan sits under the evaporator coil to catch water. Over time, the plastic can crack, warp, or become disconnected — especially in older units (5+ years). When this happens, water bypasses the pan and drips directly into your room.

Signs to look for:

• Leak appears suddenly in an older unit

• Water drips from random spots, not just the front

• You notice water staining on the wall behind the unit

• The leak persists even after a general service

Temporary fix: There's no safe DIY fix for a cracked drain pan. Turn off the unit and call a technician.

Professional fix: The drain pan needs to be replaced. Depending on your aircon model, this costs $80–$200 including labour. A good technician will source a compatible replacement and install it during the visit.

Cause 4 — Could Improper Installation Be Causing Your Aircon to Leak?

What's happening: For the drainage system to work, your indoor unit must be installed at a slight downward angle toward the drain pipe side. If a previous installer got this wrong, water will flow the wrong way inside the unit — and leak out the front.

Signs to look for:

• Unit has been leaking since the day it was installed

• Leak happens regardless of how clean the unit is

• You recently had the unit installed or moved by a different company

• You can visually see the unit is not level

Temporary fix: Turn off the unit. Do not attempt to adjust the angle yourself — the refrigerant lines are under pressure and can be damaged.

Professional fix: A qualified technician will partially uninstall the unit, correct the mounting angle, and reinstall. This is a more complex fix ($150–$300) but is a permanent solution.

Cause 5 — Is a Frozen Refrigerant Line (Low Gas) Causing the Leak?

What's happening: When refrigerant levels are too low, the evaporator coil can freeze over completely. When the ice melts, it produces much more water than the drain pan can handle, causing a dramatic leak.

Signs to look for:

• Severe water leak that suddenly starts

• Little to no cold air coming from the unit

• Visible ice or frost on the copper pipes outside the unit

• Hissing sound (possible refrigerant leak)

Temporary fix: Switch off the aircon immediately. Running a low-refrigerant unit can damage the compressor — an expensive repair.

Professional fix: A technician will inspect for refrigerant leaks, repair any leaks found, and top up the gas. If the compressor has been damaged by running low on gas, you may need a more involved repair.

Visible ice on copper pipes means critically low refrigerant — a sign of a gas leak. Turn off the unit immediately. Running a low-gas aircon risks compressor failure costing $600–$1,500 to replace.

What Should You NOT Do When Your Aircon Is Leaking?

What NOT to Do	Why
Keep running the unit	Makes the leak worse, risks electrical damage
Dismantle the unit yourself	Damages internal components, voids warranty
Pour water down the drainage pipe	Pushes blockages deeper, can damage drain pan
Ignore it and hope it stops	Leaks almost always worsen over time
Delay calling a technician	Water damage to walls and wiring costs far more than a service call

How Do You Prevent Aircon Water Leaks in Singapore?

Prevention Step	How Often	Why It Works
General aircon servicing	Every 3 months	Flushes drainage pipe, prevents 80% of leaks
Chemical wash	Annually	Keeps evaporator coil clean and ice-free
Refrigerant pressure check	Every service	Catches low gas before freezing occurs
Choose a reputable installer	At installation	Correct angle prevents structural leaks
Watch for early warning signs	Ongoing	Mild dripping becomes severe leaking within weeks

How Much Does It Cost to Fix an Aircon Water Leak in Singapore?

Issue	Typical Fix	Cost
Blocked drainage pipe	General service — pipe flush	$50/unit (Coogle rate)
Dirty evaporator coil	Chemical wash	$80–$120/unit
Cracked drain pan	Drain pan replacement	$80–$200 including labour
Improper installation	Remounting and realignment	$150–$300
Low refrigerant / gas leak	Leak repair + gas top-up	$150–$500

Frequently Asked Questions

Why is my aircon leaking water in my HDB? The most common reason is a blocked drainage pipe — dust, mould, and slime build up over time and stop water from draining properly. Other causes include a dirty evaporator coil, cracked drain pan, low refrigerant, or improper installation angle. Most leaks are fixed during a general service ($50/unit). Turn off your unit immediately and call a technician to prevent wall and floor damage.

How much does it cost to fix an aircon water leak in Singapore? Most leaks are fixed during a general service ($50/unit) that includes drainage pipe clearing. More serious leaks requiring drain pan replacement or installation correction cost $80–$300.

Can a leaking aircon cause electrical problems? Yes. Water near electrical components is dangerous. Always turn off the aircon at the circuit breaker if water is leaking heavily, especially near the power cable or control board.

Will my HDB insurance cover aircon water damage? Standard HDB fire insurance does not cover aircon-related water damage to your unit. Home contents insurance may cover damage to your belongings but usually excludes damage from poor maintenance. Check your policy.

How quickly can Coogle Aircon respond to a water leak? We aim to respond to water leak emergencies within same-day or next-day service across Singapore. WhatsApp us at 8671 6888 for the fastest response.

Can I use my aircon while waiting for the technician? No. Running a leaking aircon worsens the problem and risks electrical damage. Switch it off and use a fan or open windows until the technician arrives.

Coogle Aircon provides fast, honest diagnosis and lasting repairs for aircon water leaks across Singapore. General servicing from $50/unit — same-day or next-day response available.

BOOK AIRCON LEAK REPAIR IN SINGAPORE Aircon water leaks rarely fix themselves — and the longer you wait, the more damage occurs to your walls, flooring, and the aircon unit itself. At Coogle Aircon, we provide fast response, honest diagnosis, and lasting repairs at transparent prices.

WhatsApp: +65 8671 6888 Rates: www.coogle.com.sg/rates Email: care@coogle.com.sg

Written by the Coogle Aircon Team. Aircon water leaks are one of the most common — and most stressful — problems we fix across Singapore HDB flats every day. At Coogle Engineering Pte. Ltd. (UEN: 202568886K), we diagnose fast, explain clearly, and fix it right the first time. General servicing from $50/unit, same-day or next-day response available. Rated 4.9 stars on Google, serving all Singapore estates.