If your AC is leaking water inside, the condensate from the cooling coil isn’t reaching its exit, usually because of a blocked or disconnected drain line, a dirty filter that froze the coil, or an indoor unit that isn’t level. Switch the AC off, put a towel underneath and follow the steps below. Clearing the drain line and pan is part of a professional AC cleaning service.
Why does an AC produce water at all?
Warm room air passing over the cold coil condenses into droplets, like water on a cold glass. They collect in a drain pan and run through the drain pipe to the outside. In coastal Saihat, Qatif and Tarout, humidity climbs at night and in the early morning, so the AC makes more water and partial blockages show up quickly.
Leaking inside or dripping outside?
- From the drain pipe outdoors: normal, as that’s where the water should go. Route the end to a drain so it doesn’t stain walls or drip on passers-by.
- Around the outdoor unit in cooling mode: usually the drain pipe running beside it, or ‘sweating’ from cold copper pipes with damaged insulation.
- Ice on the pipes that melts and drips: not normal; it can mean low refrigerant or poor airflow.
- From under the indoor unit, the air outlet or down the wall: a problem. See the causes below.
Why your AC is leaking water inside
1. Blocked drain line or pan
Dust, mould and slime build up in the pan and drain line until the pan overflows into the room, sometimes with a musty smell from standing water. Daikin lists a blocked drain hose among the causes of leaks. The tell-tale sign: the indoor unit drips while little or no water comes out of the pipe outside. Flushing the line and cleaning the pan usually needs a technician.
2. Hose disconnected, torn, kinked or sitting in water
LG notes that the drain hose can come loose, tear or kink, or its end can sit in water (in a full bucket, a plant pot or buried in soil), leaving the water nowhere to go. Check the outdoor end yourself: lift it out of the water, clear any blockage and straighten kinks.
3. Dirty filter, frozen coil, melting ice
Daikin also names a dirty filter as a cause of leaks. A clogged filter cuts airflow over the coil, so the coil gets too cold and ices up; when the AC stops, the ice melts at once and the pan overflows. Clean the filter. If ice returns with weak cooling, read why an AC stops cooling, as low refrigerant may be to blame.
4. Indoor unit not level after installation
The drain pan is designed so water flows towards the outlet. If the unit tilts the wrong way, water gathers at the other end and spills over; LG lists an unlevel unit as a cause. It often appears after a new installation or a move, or when a bracket loosens. The drain pipe also needs a continuous downward slope with no rise that traps water. Re-levelling is a job for an AC installation technician.
5. Failed drain pump (cassette and concealed units)
Cassette (ceiling) and concealed units usually rely on a small pump, not gravity alone, to lift water into the drain line. If the pump or its float switch fails, water overflows from the ceiling. LG lists drain-pump failure among the causes, and some LG models show CH04 for a drain problem. This needs AC repair and maintenance.
6. High humidity and outside air getting in
LG also lists high humidity. With a door or window open, humid air keeps flowing in, the AC makes more water and droplets can form at the air outlet. Keep doors and windows shut while the AC runs and seal gaps around them, as the Saudi Energy Efficiency Center advises.
Quick guide: what you see, the likely cause and the fix
| What you see | Likely cause | Who fixes it? |
|---|---|---|
| Water under the indoor unit, none from the pipe outside | Blocked drain line or pan | Technician |
| Water plus ice on the coil or pipes | Dirty filter or low refrigerant | You (filter), then a technician |
| Leak began after installation or a move | Tilted unit, no slope, detached hose | Installation technician |
| Hose end outside submerged or kinked | Water has nowhere to go | You: free the end |
| Droplets blowing from the air outlet | Humidity, open door or window, dirty coil | You (close gaps), technician (cleaning) |
| Cassette/concealed unit leak, or LG code CH04 | Drain pump or float switch failure | Technician |
| Water from the pipe near the outdoor unit | Normal condensate drainage | Nothing; route it to a drain |
AC dripping water inside: what to do right now
- Switch the AC off, and turn off the breaker if water is near a socket or appliance.
- Put a towel or container underneath and move electronics away.
- If there’s ice on the coil or pipes, run the fan only until it melts. Don’t chip it.
- With the power off, rinse the filters and refit them once dry.
- Check the hose outlet outside: is water coming out, or is the end submerged, kinked or blocked?
- Run the AC for an hour. If dripping returns, the blockage is likely inside the line or pan: call a technician.
Safety note: don’t open the inner casing or electrical box, and don’t push sharp wires into the drain from the indoor side; you could puncture the hose or damage the pan.
Still dripping after cleaning the filter and checking the hose? Photograph the leak and the hose outlet and send them to technician Ali at Mousa Workshop on WhatsApp, or call +966 54 372 8453, daily from 8 AM to 11 PM.
What a technician checks
A professional inspection usually covers:
- A drain test: pouring a little water into the pan and watching it leave the outdoor end.
- Flushing the line and cleaning the pan, plus the filters, coil and blower if dirt caused icing.
- Checking the unit is level, then adjusting the bracket or pipe slope.
- Testing the drain pump and float on cassette and concealed units.
- Measuring refrigerant pressure if icing recurs, since low gas causes frozen coils.
- Checking pipe insulation if water drips from the copper pipes rather than the pan.
How to stop your AC leaking again
- Clean filters regularly: every two weeks in the cooling season, as Daikin, LG and the Saudi Electricity Company recommend, and after dust storms.
- Book a thorough clean before summer covering the coil, drain pan and line. Our AC cleaning schedule for the Eastern Province explains the timing.
- Get the installation right: a level unit, a pipe sloping down all the way, and an outlet that never sits in water.
- Keep doors and windows closed while the AC runs.
When to call a technician
- It’s still dripping after you’ve cleaned the filter and freed the hose end.
- Ice keeps coming back.
- Water is coming through the ceiling or near sockets.
- The leak started after the AC was installed or moved.
- An error code appears on the display.
At Mousa Workshop in Al-Salam District, Saihat, technician Ali diagnoses the cause of the leak first and tells you the cost before starting. We cover Saihat, Anak, Qatif, Tarout and Darin, Dammam, Khobar and Safwa. Book an AC clean with drain-line clearing by WhatsApp or phone, with a photo of the leak.
Sources
Frequently asked questions
Is water leaking from my AC dangerous?
The water can damage walls, gypsum ceilings and furniture, and it may reach sockets or electrical appliances below the unit. Switch the AC off and move appliances away until the cause is fixed.
Why is my AC dripping right after it was cleaned?
A little leftover wash water can drip for a short while, which is normal. If it keeps dripping, loosened dirt may have blocked the drain line, or the drain pan or hose wasn't refitted properly — ask for it to be checked.
How often should the AC drain line be checked?
Inspecting the condensate drain is part of the professional maintenance checklist from ENERGY STAR, and the Saudi Electricity Company recommends servicing your AC at least once a year. In coastal or dusty homes, it's best done before summer.
Is it normal for a window AC to drip from the back?
Yes — a window unit drains condensate out of the back, outdoors. If water runs into the room instead, the unit is probably tilted inwards or the drain holes in its base are blocked; it should tilt slightly towards the outside.