Your AC is dripping water inside the room — why, and how to fix it
Water coming off an air conditioner is normal — but it should drain outside through the hose, not pool inside your room on the wall or floor. If yours is leaking indoors, the cause is usually simple and something you can fix yourself. Work through these steps in order before you call a technician.
The problem
You notice water dripping from the indoor unit down the wall, or pooling on the floor beneath the AC, or running off the edge of the front cover. Sometimes it only leaks when the unit runs hard, or a rush of water appears after you switch it off as ice melts. All of that water is meant to leave through the drain hose to the outside — not indoors.
Likely causes
The drain hose is clogged with algae and dust (the number one cause)
An AC produces condensate water naturally and sends it outside through a thin drain hose. Over time green algae, dust and grime build up inside that hose and block it — especially in the hot, dusty climate of cities like Amman, Riyadh and Dubai. Once it's blocked the water has nowhere to go, so it backs up out of the internal tray and overflows onto the wall.
A frozen indoor coil that's now thawing
If ice built up on the coil because of a clogged filter or low refrigerant, you end up with a large block of ice. When you switch the AC off or the load drops, that ice melts all at once — more water than the tray and drain can handle, so it overflows indoors. Freezing is a symptom; its cause is usually the filter or the gas charge (the same causes as 'AC not cooling').
The unit is mounted at the wrong tilt
The indoor unit should sit tilted very slightly towards the drain-hose side so water runs out by gravity. If the installer set it dead level, or worse tilted the wrong way, water collects at the wrong end and drips indoors. This is common with rushed or cheap installations.
A cracked or overflowing drain pan
Under the coil is a plastic pan that catches the condensate before feeding it to the hose. If that pan has cracked with age, or filled with grime and overflowed, water escapes from the wrong place and drips into the room instead of reaching the hose.
A clogged filter starving airflow and freezing the coil
A dust-packed filter stops air reaching the cold coil, so the coil runs colder than it should and freezes. Then when the ice melts you get an indoor leak. Cleaning the filter prevents the freeze-thaw cycle at the source — it's the easiest preventive fix of them all.
Fix it — step by step
- Turn the AC off — and if there's ice, run the fan to thaw itFirst switch off cooling. If you see white ice on the coil or copper, set the AC to Fan mode (fan only) for an hour until the ice melts completely, and put a towel or tray underneath to catch the meltwater.Don't chip the ice off with your hand or any tool — you'll damage the fins. Let it melt on its own.
- Cut the power at the breakerAt the AC's breaker in the panel, not just with the remote. Any work on the unit must happen with the power fully off — especially where water and electricity meet.If you can't identify the breaker, kill the main. Better than a guess around water.
- Find the drain hose and clear itFollow the thin hose that runs out of the indoor unit to the outside (it usually drops down the wall or out onto a balcony). Free the outer end and clear it: blow hard down it, gently pass a flexible wire through, or use a simple hand pump to suck out the algae and sludge.If you have a wet/dry vacuum, hold it against the outer end of the hose for a few seconds — the suction pulls the algae plug out in one go.
- Flush the hose and confirm it flowsOnce the blockage is out, pour some clean water (a splash of white vinegar with it helps) into the hose from the indoor-unit end and watch it run freely out the far end. The vinegar kills the algae and slows it coming back.Repeat the flush until the water runs clear. If it's still slow, there's a plug left — blow it through again.
- Take the filter out and clean or replace itOpen the front cover, slide out the mesh filters gently, wash them in warm soapy water from the clean side so the dust is pushed out, and let them dry completely in the shade before refitting. If a filter is torn or has gone stiff like cardboard, replace it.Photograph the filters with your phone before you remove them so they go back the right way round.
- Check the unit's tiltWith a small spirit level, or even a level app on your phone, check the unit is tilted very slightly (a degree or two) towards the drain end. If it's dead level or tilted the wrong way, that's your leak — but correcting the mount is a technician's job, since the unit is heavy and the brackets have to come off.If the AC is new and has leaked since day one, it's almost certainly an install fault — go back to whoever fitted it.
- Inspect the drain panWith the filter out, you'll see a plastic pan under the coil. Wipe out any grime and algae with a damp cloth and check there are no cracks or splits. If the pan is cracked it needs replacing — and that's a technician's job.A little diluted bleach or vinegar in the pan keeps the algae from coming back for longer.
- Power up, run it and watchRefit the dry filters, close the cover, turn the breaker back on, and run the AC on Cool. Watch it for at least half an hour: water should leave only through the outdoor hose, with not a single drip indoors.Lay a dry tissue under the indoor unit on the first run — if it stays dry, you've solved it.
Tools & parts you'll need
When to call a professional
Call an AC technician if: water still drips after you've cleared the hose, filter and pan; the drain pan is cracked and needs replacing; the unit is mounted at the wrong tilt and needs re-fitting; the coil freezes again after cleaning (a sign of low refrigerant); or you see oil or a greasy film on the copper joints (a refrigerant leak). And never try to open the cooling circuit or top up refrigerant yourself — it's under high pressure, will give you an instant freeze burn, and is strictly a technician's job with the right tools.
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Why is my AC dripping water inside the room in the first place?
An AC naturally produces condensate from the humidity in the air, and all of it should drain outside through the hose. When it drips indoors, the water hasn't found its way to the hose — usually the hose is blocked with algae, the pan is overflowing, or the unit is tilted the wrong way. It's not usually a serious fault, but fix it quickly before it damages the wall.
How do I know if the drain hose is blocked?
Go to the outer end of the hose and run the AC — if the unit is running but no water comes out of the hose outside while it's dripping indoors, the hose is definitely blocked. Pour a cup of water into the indoor-unit end and see if it comes out the far end; if it backs up or sits still, there's a blockage.
Can I put something in the hose to stop the algae coming back?
Yes. Pour a cup of white vinegar or diluted bleach solution into the hose every month or two in summer — it kills the algae and stops it building up again. Vinegar is gentler on the plastic and the smell clears fast. It's a simple habit that saves you the leak every season.
It only leaks when it runs hard or after I switch it off — why?
That's a sign of freezing. The coil freezes because of a clogged filter or low refrigerant, and when the ice melts it releases more water than the drain can handle, so it overflows. Clean the filter first; if it freezes again after cleaning, it's a refrigerant problem and a technician's job. See the 'AC not cooling' guide for the detail.
The AC is new and has leaked since the day it was installed
That's almost certainly an install fault — the unit is set level or tilted the wrong way, so water can't run to the hose. Or the hose itself is kinked or routed uphill somewhere. Go back to whoever installed it and have them correct the tilt — it's covered by the install warranty and you shouldn't have to pay for it.
The leak has wet the wall and now there's mould — what do I do?
First stop the source of water (clear the drain). Then dry the wall thoroughly, ventilate the room, and clean the mould with a diluted bleach solution. If the damp has reached the paint or plaster and it's flaking, it'll need treating and repainting once fully dry. Most important is to stop the leak recurring so the mould doesn't return.