Generic HVAC Window AC Leaking Water Inside: How to Fix It Yourself
When a window AC drips water inside your room, the most common cause is that the unit is tilted forward instead of slightly backward. AC units are designed to drain condensation out the back. A simple tilt adjustment usually stops the leak right away.
⚠️ Safety First
- Unplug the unit before doing any work.
- Wipe up pooled water immediately to avoid floor damage or slipping.
- Use caution when adjusting the unit in the window — have someone help if it is heavy.
Parts You May Need
Step-by-Step Repair
- 1
Unplug the unit and mop up water
Pull the plug from the wall. Use towels to soak up any water on the floor or windowsill. This prevents water damage and keeps the area safe while you work.
- 2
Check the tilt of the unit
Place a level on top of the unit from front to back. The back of the unit (the side facing outside) should be slightly lower than the front — about half an inch. This lets condensation drain out the rear. If the unit is level or tilted forward, that is your problem.
- 3
Adjust the tilt
Most window AC brackets have adjustable legs or support arms. Raise the front or lower the back until you get a slight backward tilt. If there are no adjustable legs, you can place a small shim (a piece of wood or a folded cardboard strip) under the front edge of the unit inside the window frame.
- 4
Clear the drain hole
Look at the bottom-rear of the unit for a small drain hole or channel. Over time, dust and algae can clog it. Use a pipe cleaner or small brush to clear it out. Some units have a drain plug — if yours does, make sure it is not fully sealed when you want water to drain freely.
- 5
Check the window seal
If hot humid air is leaking in around the unit, it creates extra condensation that overwhelms the drain system. Make sure the foam side panels and top seal are snug against the window frame with no gaps. Replace the foam if it is compressed or torn.
- 6
Plug in and monitor
Plug the unit back in and run it for an hour. Check for dripping every 15 minutes. The leak should be gone. If water still drips inside, the drain pan inside the unit may be cracked, which is a harder fix.
If That Didn't Work
- Clogged drain hole or drain channel at the rear of the unit
- Cracked or rusted internal drain pan
- Very high humidity causing excessive condensation
- Air gaps around the window seal letting humid air inside
When to Call a Professional
If adjusting the tilt and clearing the drain does not stop the leak, the internal drain pan may be cracked. Replacing it is not easy on most window units. At that point, a new unit is often more cost-effective than a repair.
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Disclaimer: This guide is for informational and educational purposes only and does not constitute professional repair advice. All repairs are performed at your own risk. RepairItFree.com is not liable for any personal injury, property damage, device damage, voided warranties, or other losses resulting from the use of this information.
If you are unsure about any step — especially anything involving electricity, gas, water, or refrigerant — stop and consult a qualified professional. Your safety is more important than saving money.
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