Why is rain coming through my window air conditioner?

Author: Vella Collier  |  Last update: Friday, October 31, 2025

Window Unit Not Properly Installed. Leaks can happen just about anywhere, and when you've not properly installed or sealed your window AC unit all that rain that's outside will find its way inside rather easily. Luckily, this is the easiest one to avoid!

How to keep rain from coming in around window air conditioner?

Your first line of defense is weather stripping. If your AC comes with weather stripping, use it. If you still notice any gaps around your AC, there's a simple solution. Add a weather seal wherever you see gaps.

How do I stop my window AC unit from leaking water inside?

How to Diagnose and Fix a Leaky Window AC Unit
  1. Clean the Filter. Start by cleaning the air filter on your window air conditioner. ...
  2. Ensure Your AC Unit Has Adequate Fall. The window air conditioner should slope to the exterior of the home. ...
  3. Clear the Drain. ...
  4. Inspect the Drain Pan. ...
  5. Replace the Window AC Unit.

Why is rain coming through my air conditioner?

There are a handful of reasons why your AC vents could leak without an outside water source like rain. Common issues include: Clogged Condensate Drain Line: The condensate drain line for your AC runs from the system to the outside of the home. The condensation on the evaporator coils exits via this drain.

How to unclog a window AC drain line?

  • Turn off the A/C.
  • Locate the drain line, typically a PVC pipe near the indoor unit.
  • Use a wet/dry vacuum to suction out the clog or debris.
  • You can also flush the line with a mixture of water and vinegar.
  • Regular maintenance helps prevent future clogs.

Should I Be Worried About Rain or Weather Damage to My A/C Unit?

How do you know if your AC drain line is clogged?

A clogged AC drain line symptoms include:
  1. Musty, moldy smell near your indoor unit or in air from the registers/vents.
  2. Standing water near the indoor unit.
  3. Water damage in areas near the indoor unit.
  4. AC system is not cooling your home.
  5. AC system shuts down or doesn't turn on.

How to drain water out of window air conditioner?

If your window AC unit has an option to attach a drain hose, follow these steps:
  1. Attach the Hose: Connect one end of the hose to the drain hole. ...
  2. Position the Hose: Place the other end of the hose into a bucket or direct it outside where the water can safely drain away.

Can I still use my AC if it's leaking water?

Can I still use my AC if it's leaking water? It's not recommended to use your AC if it's leaking water. Water leaks often indicate problems like a clogged drain line, frozen evaporator coils, or a damaged condensate pan. Running the AC could worsen the issue, leading to water damage or further mechanical problems.

How do I stop water from coming into my air conditioner?

To fix water dripping from the split AC indoor unit, start by cleaning the drain line to remove blockages. Replace or clean the air filters to ensure proper airflow. Check for refrigerant leaks and refill if necessary. Regular maintenance can prevent AC indoor unit water leakage and ensure optimal performance.

Where is the drain hole on a window AC?

In older window units, they'll usually be located on the bottom of the outside part of the unit, fairly visible. In newer units with a drain pan, the drain holes are often closer together, since the pan drains through a single hole in its bottom.

Why is water splashing in my window air conditioner?

If your window air conditioner sounds like water, including running or splashing sounds, it indicates you may have a problem and need air conditioner repair. It might mean your AC isn't training. This could cause the drip pan to overflow and cause a leak.

What does it mean when your air conditioner leaks water inside?

The most common cause of AC leaking water outside or inside at home is because your unit has a clogged condensate drain line. Often, the condensate line gets clogged with dirt and dust that passes through it. Over time, it mixes with the moisture of the air conditioning unit and sticks to the sides of the drain line.

Why is my window AC blowing out black stuff?

Inefficient filters can lead to dirt and dust being circulated through the air ducts and eventually released into your home when the AC runs. If this is happening, replacing or cleaning the filter should do the trick.

How to seal up a window AC unit?

Foam Tape. Most window AC units come with foam tape designed for insulation. This weatherstrip tape, readily available online, is easy to use and adheres well to plastic surfaces. You can use foam tape to insulate the sides around your window AC and below the window.

How to stop rain from coming in the window?

To fix window leaks, start by identifying the source of the leak. Check for gaps, cracks, or damaged seals around the window frame. Apply a high-quality caulk or weatherstripping to seal these areas. For more extensive damage, consider professional repair or full window replacement to ensure long-lasting protection.

Why is my window AC leaking water from the bottom?

If water is dripping from an AC unit indoors, the reason may be one of the following: A blocked drainage tube: Dust from the air can mix with water and create an obstruction. A damaged drain pan or blocked water outlet: A damaged pan produces drips in all the wrong places, and a blocked water outlet causes an overflow.

What to do when your air conditioner is full of water?

How do you get water out of a drain pan?
  1. Turn off the power supply to AC. ...
  2. Check for leaking from the seams of the unit. ...
  3. Check to see if water is dripping from the drain hose that's located at the back of the unit. ...
  4. Check for blockages in the drainage system. ...
  5. Check for cracks in your unit's drip pan.

What is the dry mode on my air conditioner?

By using "Dry Mode", the AC unit extracts excess moisture from the air, creating a more pleasant, cool and breathable atmosphere. When "Dry Mode" is activated, the AC unit's compressor and fan operate at a low and slow enough speed to dehumidify the air without causing a significant drop in temperature.

Is AC leaking water an emergency?

A leak from your air conditioner can cause significant damage to the system. Whether there's more moisture on or near your AC than usual or water is ponding near the drain line, consider it an emergency. The damage from water can quickly escalate and spread to nearby equipment, materials, and furnishings.

Where is the condensate drain line?

How do I find my AC drain line? Your AC has a condensate drain line running from the indoor to the outdoor unit. You'll find the end of the drain line somewhere near the outdoor unit (usually a copper or white PVC pipe). As for the access point, look for a vertical pipe with a cap near the indoor unit.

Why is my window AC leaking water reddit?

When enough moisture condenses inside the unit it will drip to the bottom. The manufacture puts hole(s) in the bottom back of the unit for this to drip outside onto the ground and away from anything you care about. You probably mounted your unit with it leaning towards the inside of the house.

Why is my window air conditioner full of water after rain?

However, if your window air conditioner is full of water after rain, you have a drainage issue. There shouldn't be any standing water in your AC after a rainstorm, since standing water can damage internal components in a way normal rainfall doesn't.

How do I stop water from coming out of my air conditioner?

Here are 5 possible solutions to fix the issue
  1. Seal or Replace the Drain Pan. A damaged drain pan must be meticulously and firmly sealed. ...
  2. Clean the Drain Line. Additionally, you must regularly clear your drain pipe.
  3. Fix Condensation Build-Up. Condensation build-up can cause water leaks from the AC. ...
  4. Correct Installation.

Do all window air conditioners drain water?

Most modern window air conditioners create condensation which drips down to the pan on the bottom of the unit. There are no drain holes or plugs used to remove the water as was the case with older style window AC units. When the water builds up it is distributed by the fan sling and thrown up against the condenser.

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