An AC leaking water is usually dealing with condensation that has nowhere to go. Your AC pulls moisture out of humid air, and that water is meant to leave through a drain. When the drain is blocked, the filter or coil is dirty, or something else has failed, it spills into your room instead. Switch the unit off, check the filter and the drain outlet, and call a technician if the water returns.
In a Dubai summer the problem shows up fast, because the air is humid and the unit runs for most of the day. A unit that drips a little in cool weather can leave a lot more water behind when it runs most of the day in summer. This guide explains why it happens, what you can safely check yourself, and where DIY should stop.
Disclosure: this is a sample guide written by LeadDesk.ae to show the kind of article it delivers. It uses the Dubai company named in the section on when to call a technician as its worked example; that company did not commission it and does not endorse it. What the guide says about that company comes from the company's own website, read in October 2026; Just Green has not tested its service.
Why does an AC unit produce water at all?
Cooling air also dries it. Warm, humid indoor air passes over a cold coil inside the unit, and moisture condenses on the coil the way it does on a cold glass. That water drips into a pan and runs out through a drain line, usually a small pipe that leads outside or to a drain point.
So a little water moving through the system is normal. Water appearing where you can see it is not. The question is always the same: where did the water stop flowing? The answer is usually one of four places.
What are the common causes of AC leaking water?
These are general causes found across split, ducted and window systems. They are general guidance, not a diagnosis of your unit.
1. A blocked condensate drain. Dust, slime and debris build up in the drain line and the pan backs up. A blocked drain is a common reason water ends up indoors. The technical name is the condensate drain, and it is the reason a drain flush is part of a proper service.
2. A dirty filter. A clogged filter restricts airflow across the coil. The coil can get too cold, ice over, and then melt faster than the pan can handle. The result looks like a sudden leak after a long run.
3. A dirty or iced-up coil. Dirt on the coil does much the same as a blocked filter: poor airflow, a coil that is too cold, and meltwater overflowing the pan.
4. A drain line that is damaged or poorly sloped. If the pipe has cracked, come loose or no longer slopes towards its outlet, water sits or escapes through the join. Indoor units that have been knocked, or a pipe that has sagged, often show it.
5. Something unexpected. Water can also point to a fault you cannot see from the outside, such as a failed pan or a refrigerant problem that makes the coil ice up. Water leaking is one of the common AC faults, alongside a unit not cooling, tripping or not turning on, strange noise, a musty smell and a gas leak. If your unit shows two of these together, treat it as more than a drain problem.
What should I check first, safely?
Do these in order. They need no tools and nothing here involves opening the unit or touching wiring.
- Switch the unit off at the thermostat or remote. Keep dripping water away from sockets, cables and furniture. If water is near electrical fittings, also switch off at the breaker and do not touch the unit.
- Look at where the water is. Under the indoor unit, along the wall, at a ceiling cassette, or at a joint in the pipe tells you where it is escaping.
- Check the filter. Slide it out if your model allows. If it is grey and matted, rinse or replace it as the maker advises and let it dry fully before refitting.
- Check the outdoor drain outlet. On many split systems you can see where the drain pipe ends. If nothing drips there while the unit runs and water is falling indoors, the line is probably blocked.
- Look for ice. Frost on the pipes or the coil means airflow or refrigerant trouble. Keep the unit off until the ice has melted completely, and clean the filter while you wait.
- Once the ice is gone and the filter is dry and refitted, run the unit briefly. If it works and nothing drips, the filter was the likely cause. If ice or water returns, stop and call a technician; do not run it again.
Decision table: what you see and what to do
| What you see | Likely cause (general) | Safe action | Call a technician? |
|---|---|---|---|
| Steady drip under the indoor unit, filter grey | Dirty filter and iced coil | Clean the filter, let ice melt, test | Only if it returns |
| Water at the wall below the unit, nothing at the outdoor outlet | Blocked condensate drain | Switch off, mop up, do not poke the pipe | Yes, drain needs flushing |
| Water only at a pipe joint or along the pipe | Loose or damaged drain pipe | Switch off, catch water | Yes |
| Ice on pipes or coil, weak cooling | Airflow or refrigerant problem | Switch off, let it thaw | Yes |
| Water plus a musty smell | Moisture in the unit | Switch off, clean filter | Yes, the unit needs cleaning |
| Water plus tripping or a burning smell | Electrical fault | Switch off at the breaker, stay away | Yes, immediately |
Why does a leak matter beyond the mess?
Standing water is not only a floor and ceiling problem. The US Environmental Protection Agency says the key to mold control is moisture control, and that wet areas and items should be dried within 24-48 hours, in most cases before mold will grow. Its guide to mold, moisture and your home also lists keeping air conditioning drip pans clean and drain lines unobstructed. For an AC leak, that means mopping up and drying the area the same day and fixing the source.
There is also an energy side, which is why this belongs on a home-efficiency blog. A unit with a dirty filter or coil works against restricted airflow, and a leak is often the first visible sign. For the wider picture of cooling that is uneven or weak, our guide on why some rooms are hotter or colder than the rest walks through airflow and thermostat checks, and the energy-efficient home guide shows where cooling fits among the changes worth making first.
What should I not do?
- Do not poke wire or a stick into the drain pipe. You can push the blockage deeper or crack the pipe.
- Do not keep running a leaking unit. The water can reach wiring, ceilings and neighbours below, which matters in an apartment.
- Do not top up or handle refrigerant yourself. That is work for a technician.
- Do not ignore a repeat leak. If you have cleaned the filter and the water comes back, something else is wrong.
If you rent, tell your landlord or property manager early. Water through a ceiling can become a dispute between tenants, owners and neighbours, and a dated message and a photo help every party.
When is it time to call a technician?
Call when a leak returns after you cleaned the filter, when you see ice, when water touches anything electrical, or when the leak comes with another fault such as no cooling or a strange noise. For a ceiling cassette or a ducted system, call straight away, as these are harder to inspect and the water can collect above a ceiling out of sight.
One example of who does this work in Dubai is WEFIX, a Dubai maintenance company based in Al Quoz. On its own website it says it works across Dubai on AC, electrical, plumbing, handyman, painting and renovation jobs, with separate teams by trade, describes a dedicated AC team, and says it works on split, ducted, central, VRF/VRV, cassette and window units, and that AC repair starts at AED 350 + VAT. Its stated process is that the technician diagnoses on site, writes the price down and you decide; if the unit shows something unexpected they stop and re-quote. Those are the company's own statements, so judge them by asking the same questions of any provider.
How to judge any AC repair provider
Use this short list, whoever you call:
- Is the price written down before work starts?
- Does the technician name the cause of the leak, not just "clean the unit"?
- What happens if a different fault turns up mid-visit?
- Does the quote say what is included and what is extra?
A provider that answers all four plainly is easier to trust than one that offers the lowest figure on the phone.
How do I stop it happening again?
Prevention is mostly routine. A proper service visit covers six steps: thermostat and controls, electrical connections, lubricating moving parts, a condensate drain flush, a filter and coil clean, and a full performance test. The drain flush and the filter and coil clean are the two steps that target leaks directly.
Between services, check the filter regularly during the hottest months, keep the area around the indoor unit clear, and notice early signs: a damp patch, a faint musty smell, or a unit that cools less than it did. Catching a drain problem at the damp-patch stage usually means a simpler fix than waiting until a ceiling is stained.
Frequently Asked Questions
Is it normal for an AC to drip a little?
Water leaving through the drain pipe outside is normal, especially in humid weather. Water dripping inside, along a wall, or from the indoor unit is not, and it means the water has not reached the drain.
Can I fix a blocked AC drain myself?
Cleaning the filter is safe for most people. Clearing the drain line is better left to a technician, because forcing something into the pipe can damage it or push the blockage further in.
Can an AC leak cause electrical problems?
It can. Water that reaches sockets, cables or the unit's own electrics is a safety risk. Switch the unit off, and if water is near electrics, switch off at the breaker and call a technician. Do not touch wet electrical parts.
Is a leaking AC a sign I need a new unit?
Often not. Many leaks trace back to a blocked drain, a dirty filter or coil, or a damaged pipe, all of which can be fixed. A technician who has diagnosed the cause can tell you whether the unit itself is at fault, and the repair should be priced in writing first.
Who pays if the leak damages the apartment below?
That depends on your tenancy agreement and building rules, and this guide cannot say. Report the leak to your landlord or building management quickly, keep photos, and check your own contract.
Switch Off, Check, Then Call
A leaking AC is usually a drain or airflow problem that shows up when the weather is hardest on the unit. Turn it off, check the filter and the drain outlet, and do not keep running it. If the water comes back, or you see ice, a smell or anything electrical, call a technician and ask for the price in writing before work starts. For more plain-language guides to cooling, repair and running a home well, explore the rest of Just Green.