How To Fix It

How To Fix Air Conditioner Leaking Water Inside?

Having an air conditioner is a great luxury, especially in the hot months when you want to be cool and comfortable inside your home. However, a leaking air conditioner can cause quite a mess and lots of stress. So, how do you fix an air conditioner leaking water inside? 

You can fix an air conditioner leaking water inside by unclogging the condensate drain line, replacing the drain pan, or repairing bandages on the drain hose. You may also replace the air filter or adjust the refrigerant levels.

In the rest of this article, I’ll describe some of the most common causes of a leaky air conditioner and how to fix them. After reading this article, you’ll be able to fix the mess of an air conditioner leaking water inside and enjoy the cool air an air conditioner provides. 

1. Unclog the Condensate Drain Line

One of the most important parts of an air conditioning system is the condensate drain line. This line removes the pooled condensation from the cooled air out of your home. This moisture must be removed from the building; otherwise, you risk encouraging mildew or corrosion. 

Unfortunately, the condensate drain line can easily become the home for dirt, debris, bugs, and other unwanted sludge. Once too much of this muck gathers up, the water will build up in the condenser pan. Eventually, this will create leaks and drip water. 

You can unclog the condensate drain line yourself, although if you don’t feel comfortable doing so, you can always contact an HVAC professional for help. Here’s how to clean out the condensate drain line: 

  1. Turn off the air conditioner. 
  2. Remove the plastic cap from the PVC pipe. 
  3. Look inside the drain to see what’s causing the clog. If you can, remove the clog with gloved hands. 
  4. Pour a cup of distilled white vinegar into the drain line. 
  5. Put the cap back on. 
  6. Wait at least an hour and a half, then turn the air conditioner back on. 

Distilled white vinegar is a gentle cleanser that won’t cause any damage to the drain line. I recommend this Aunt Fannie’s Distilled White Cleaning Vinegar from Amazon.com because it doesn’t leave any residue behind when you use it to clean, and it is strong enough to pick up grime and break down any grease or mineral deposits. I also like that it is made with simple ingredients and contains no added scents or dyes.  

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A clogged condensate drain line doesn’t just cause leaks. It can also cause a myriad of other problems. For example, a clog may encourage mildew or mold growth around the air conditioner, which is a health hazard and doesn’t smell pleasant.

If you notice a smell in your air conditioner, I suggest you read my article on how to get rid of it. 

Read: Do You Have To Vent A Portable Air Conditioner In Heat Mode?

2. Replace the Drain Pan

Another important part of your air conditioning system is the drain pan. This is where all the condensed water droplets formed by humidity and air cooling collect. After the water pools in the pan, it’ll flow out of your house through the drain line. 

However, if the pan is damaged or has a hole, the condensed water will leak out. Unfortunately, this problem isn’t uncommon because many drain pans are made from cheap plastic, which can easily break over time. 

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If you need to replace the drip pan, follow these steps: 

  1. Purchase a new drip pan compatible with your air conditioner’s make and model. 
  2. Turn off the air conditioner. 
  3. If your drain pan is attached with screws, you can remove it yourself. If it is welded into place, it’s better to have an HVAC professional help.
  4. Replace the old pan with the new one. Screw it into place so that it is snug and secure. 
  5. Close the access panel. 
  6. Turn the air conditioner back on. 

Many people underestimate the importance of the drain pan, but it is one of the first parts you should check if your air conditioner starts leaking water inside.  

Read: Why Is My Air Conditioner Not Dripping/Draining Water?

3. Repair Any Bandages on the Drain Hose

If your drain hose has any bandages because of past damage, the waterproof tape may have come undone and created a place where water can leak out. You should have a professional check your drain hose and re-do any past repairs.

You can check the bandages and replace any old or peeling waterproof tape to save a little money. I suggest using this Tapel Butyl Waterproof Tape for Leaks from Amazon.com. This high-quality tape offers airtight sealing, so you are unlikely to experience any leaks once you replace your old tape with this one. The tape can shut off moisture, vapor, chemicals, and other potential leaks.  

4. Replace the Air Filter 

If air cannot pass through the air filter because of damage or clogging, the evaporator coils will likely freeze and start to leak when they thaw out. It is best to avoid this situation by replacing your air filter at least every ninety days, although the more frequent, the better. I especially recommend keeping up with your air filter replacement in hotter months when you’re using the air conditioner more frequently. 

For guidance on replacing your air conditioner air filter, I suggest watching the following YouTube video: 

Not only will the air conditioner start to leak if the air filter is clogged, but it won’t work as well as it should and cool your home properly. For more information, I recommend reading my article on how to improve air conditioner efficiency

Read: Can An Attic Be Used To Vent A Portable Air Conditioner?

5. Adjust Your Refrigerant Levels

If your air conditioner refrigerant levels are too low, the evaporator coil will get too cold, and in extremely low temperatures, it will freeze over. If this happens, it will start to drip and leak water once the temperature goes up and it starts to thaw. This leakage can quickly fill up the drain pan and cause leaking inside.

You’ll probably notice relatively quickly if the refrigerant levels are too low. When the refrigerant levels are too cold, the air conditioning won’t work, and you won’t feel your air getting any cooler even when everything is turned on. Another symptom of wacky refrigerant levels is a loud sound from your air conditioner. For more information, check out my article on how to reduce noise from an air conditioner unit

Here’s how to check your refrigerant levels when they’re too low: 

  1. Turn off the air conditioning system. 
  2. Look at your air conditioner for a type plate or card with various information on it. This card should tell you the refrigerant type. 
  3. Use a refrigerant slider to determine the condensation and evaporation temperatures. 
  4. Use a thermometer to measure the temperature. 
  5. Calculate the superheating and subcooling. 

If you follow these steps and confirm that your refrigerant levels are too low, you should call a professional to adjust the refrigerant levels for you. 


An air conditioner that is leaking water inside is an inconvenience and can be quite messy. Luckily, fixing this issue is relatively straightforward. You can solve the problem by unclogging the condensate drain line, replacing the drain pan, repairing drain hose bandages, replacing the air filter, or adjusting the refrigerant levels.