Common Causes of AC Water Leakage

Identify causes of AC water leakage, including window AC water leakage and water leakage from the indoor unit. Trust Sandium for expert solutions and prevention tips.

Updated on Oct 23, 2023
5 min read
Common Causes of AC Water Leakage

A lot of people are troubled by leaking air conditioners. There are multiple reasons for your AC to be leaking water. The inside unit of an air conditioner houses the evaporator coil. This is the component responsible for cooling warm air that gets blown over it. Condensation is formed on the coil similarly to water droplets forming on a glass of cold water on a hot summer day in the Bay Area.

This moisture is supposed to drip down into the drain pan through a condensate drain line. Most air conditioners have a white colored PVC pipe leading away from the indoor AC unit and outside the house. However, sometimes it can just so happen that the water starts dripping inside your home. These are a few causes for that.

1. Condensate Drain Line is Clogged

One of the most common reasons for water leaking inside the house is a clogged condensate drain line. This can result in the water from the AC to drain inside the home rather than outside. It is common for drain lines to easily get clogged with dirt, dust, mold, and sludge. This causes water to back up inside the pipe.

You will need to unclog the drain pipe in this case. There are various ways of unclogging the pipe. You can always use a dry/wet vac on the condensate drain pipe to clear the debris. However, it is always recommended to get a professional take care of the issue. They have a special vacuum that is gentle yet effective to remove all the blocked material.

2. Rusted or Damaged Drain Pan

Older air conditioners running for more than 12 to 15 years usually have drain pans that are rusted through. The drain pan may also get damaged over the years that cause water to fall right through. You may need to replace the drain pan in this situation.

3. Condensate Pump is Broken

Is your indoor AC and furnace unit installed in your home’s basement? If yes, then your system has a condensate pump for pumping the drain water outside your house. Your unit may not be able to pump the water outside if the condensate pump breaks. In this case you should consider calling a professional technician to replace or repair the pump.

4. Air Filter is Dirty

The evaporator coil does not get enough air flowing over it when the air filter is choked. The evaporator coil in this situation tends to get very cold and freeze over. Water tends to start dripping when the ice finally thaws. In most cases, the drain pan is not sufficiently big enough to handle the excess amount of dripping water. You should check your air filter regularly and change it if required. In fact, you should make it a point to change the air filter every three months.

5. Low Refrigerant Levels

Low refrigerant in the air conditioner causes similar reactions as a dirty air filter. It causes the evaporator coil to freeze. Water will begin overflowing in the drain pan when the coil eventually starts to melt. You should have a technician take a look at the refrigerant levels during periodic AC maintenance. A hissing or bubbling sound coming from the air conditioner usually means low refrigerant levels.

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