Here’s Why Your Window AC Is Leaking Water, and What You Can Do to Fix It

We live in a relatively modern world, where we witness impressive advancements every other day. However, as you may have heard, every great thing comes with its consequences. The same holds for window air conditioners.

You’ve probably noticed that your window AC leaks water occasionally, especially in the summers. As a result, you must be wondering why the leakage arises and what you can do to fix it. If not, now is the time to start.

Knowing this will help you investigate why the leak is occurring, and save you hundreds of dollars on issues that you can resolve on your own.

Your air conditioner may be leaking water due to various factors, including poor repair, lack of maintenance, or the weather. Water leaking from your window air conditioner is not a pleasant experience, and it isn’t something you should accept as a regular part of living in a house, either.

To help you deal with this problem, and if required, solve it, we’ll go over a few reasons why there could be a water leak in the first place.

Top 5 Reasons Why Your Window AC Is Leaking Water

Here are 5 of the most important reasons why your window AC may be leaking water. So have a brief look at them to determine what causes this trouble, and learn how to solve it.

1. Air Filters

Air filters are pretty popular in the air conditioning industry since practically every user or professional tries to replace the filters whenever a problem arrives. That’s understandable since in most cases, these filters are the source of the problem.

The most likely issue is that the air filters become overly clogged and cause a massive blockage. This barrier prevents air from passing through, and that is where the freezing occurs. Instead of flowing through the filters, the cold air chills the evaporator coil and causes it to freeze. It is evident that once it freezes, it melts as well, which is why you can see water trickling through your window AC.

The amount of water that leaks mostly depends on the temperature that you set for your air conditioner. If you set it below 20 degrees Celsius, you may see an excessive leakage because of the extensive freezing. However, if you run it at a moderate temperature, the leakage may not be as bad.

  • Solution

If we talk about the solution, it is pretty apparent what you need to do, right? You will have to see if your filters are in good working condition and aren’t clogged. But if they are, you will have to replace them.

Of course, it is best to check the filters at least once a month to not run into any major hurdles.

2. Blockage of the Condensation Drain

Since we are dealing with water leaks, you’ll hear the word “blockage” almost everywhere. This time, the problem might be caused by the drainpipe rather than the filters. When it becomes blocked, though, the water overflows, causing leakage in your air conditioner.

But how can the condensation drain become clogged? The reason is that dirt and mold begin to build up in the drain over time. As soon as it grows, the water starts to get blocked, resulting in leakage. Keep in mind that if the drain becomes clogged, there might be a lot of water leakage. As a result, you must address the issue as soon as possible to avoid further damage to your air conditioner.

  • Solution

The blocked drain pipe is relatively simple to repair, although it may require some additional equipment. All you need is a vacuum with enough power to remove any dirt, dust, or mold from the condensation pipe. To be clear, the drainpipe is either outside or near the outer of your house, depending on your preferences. That is where you have to perform the suction.

Running the vacuum on high to suck everything that is causing a blockage is also a good approach. However, you should do this at least once a month to ensure that the condensation drainpipe remains clear.

3. Broken Drain Pan

We have talked about a clogged condensation drain, but do you know where the water stores before the overflow? If the condensation pipe is blocked, as we discussed above, the water will leak or overflow. But if the drainpipe is in bad shape, the water will never reach that point of overflowing since it won’t even stay put in the pan correctly.

As a result, your window AC will start to leak water if your drainpipe is broken or damaged. Not only that, but unlike the cases that we outlined earlier, water will leak the whole time you are operating your air conditioner.

  • Solution

The most reliable solution to this issue is to get a new drain pan that you may integrate into your window AC. This will fix the problem and get the system working again. If you don’t want to spend a lot of money and would rather go for a less expensive option, you can choose to have your current drain pipe welded instead. However, make sure that the welding is done flawlessly so that it can provide you with long-term durability.

This problem usually arises after years of use, when the AC becomes rusty and eventually breaks down. This entire process can take a year or more, which is why you won’t have to look into it every month.

4. Problems With the Condensation Pump

This problem only affects people who have their window air conditioner running in the basement or below ground level. In this case, instead of drain pipes, ACs use condensation pumps to return the water to the ground level and excrete it. Without a pump, it will be difficult to discharge the water since the stored liquid will remain in the pan and overflow when there is no way out.

As a result, if the condensation pump stops working, the water in the pipe will be pumped out as well. This is where the overflow starts, resulting in water leaks, which are inconvenient for the users.

  • Solution

Unfortunately, to solve the problem, you will have to spend some extra bucks. If you are lucky enough, your pump will start working simply by allowing the technician to do their job. If not, you will need to replace the pump in your AC for it to start pumping water again.

With that said, this is one of the less common issues you may encounter. That is because, for starters, not many individuals have their air conditioners below ground level. Secondly, pumps are typically used for a much longer time rather than a standard period.

5. Low Refrigerant Levels

This one may seem similar to the first case where the evaporator coil gets frozen, but it has some slight variations. In this situation, the refrigerant lines are to be blamed, which you should be on the lookout for.

When the refrigerant levels drop, the pressure building inside the refrigerant pipes gets drastically low. As a result, heat transfer is restricted, which causes the refrigerant lines to freeze.

Heat transfer is one of the most essential AC features since there would be no efficient flow of cold or heat without it. And, of course, when those refrigerant lines melt in the end, water leaks from your window air conditioner.

  • Solution

To fix this issue, you will need to refill the refrigerant or fluid to build the refrigerant lines’ pressure. It is a somewhat tricky task, and you may wish to get the help of an expert. However, if you have prior knowledge or experience, you can very well go ahead and attempt to fix the problem yourself.

Should You Implement the Solutions Yourself or Opt for a Technician?

This is one of the things you may be asking yourself when in a situation that could cost you a fortune if something goes wrong. So, what should you do if you have a water leak? Is it a good idea to inspect the issue and put the remedy in place yourself? Or is it better to hire a technician or professional to take care of the problem instead?

If your window air conditioner is leaking water due to clogged filters or a blocked drain pipe, you can most likely fix the problem on your own. However, if the task is more complicated, such as replacing the pump or refilling the refrigerant, it is better to take the help of a technician. But keep in mind that you will probably need to pay a hefty service fee for the assistance. So, if you can manage a task yourself, go for it without stressing yourself out with the extra work.


Fixing a water leak in your window air conditioner isn’t as difficult as it may appear. In most cases, you can solve the problem in a few simple steps. Therefore, it’s best not to panic when faced with such a situation and instead, try to figure out what’s causing the issue. You can go through the steps mentioned above, and you’ll most probably get the answer straight away.

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