AC Drain Line Clogged (7 Causes & 2 Solutions)

 Very few things can truly rock our boat when it comes to household items malfunctioning. That’s why AC’s are often forgotten about. Once we buy and install them, we tend to forget about them. The truth is – without the proper maintenance and attention – AC can get clogged too. And before you doubt the importance of this problem, tolerating the unbearable heat will prove you wrong. So – what does one do with the AC drain line clogged?

AC Drain Line Clogged – Causes   


There are many things that can clog your AC drain line, most of them being debris, leaves, and other nature’s waste.

Typically, what happens prior to the clogging are prolonged periods of changing weather. This mostly includes extreme weathers of heavy rain and/or snow and storms.

Apart from that, extreme fluctuations in temperature can also have a negative impact on your outside unit.

Why does this happen and why?

To explain that, we need to shortly discuss the functioning of your AC. AC’s are a part of  HVAC units, designed for cooling, heating, and humidifying your home.

The AC’s are designed in a way that produces moisture, which is then captured on a condensation tray or pan. This tray is connected to the drainpipe, which carries the collected moisture to the outdoors.

Now, imagine the drainpipe getting clogged with debris or leaves after a huge flood. It will then be obstructed to carry out the excess moisture, which can lead to leaks or other damages.

AC Drain Line Clogged – Symptoms  

clogged ac drain line

If you’re worried that your AC drain line might be clogged, then you’ve come to the right spot.

Ease your worries by going through these next 6 causes.

This will help you determine if your AC drain line is indeed clogged.

If you find out that this is not the case, you may want to consult an HVAC technician for help.

  1. AC Not Working 

This is the most obvious, telltale sign that something is wrong with your AC’s system.

If your AC is not working at all, this could be an indicator of the clogged drain pipe. However, this is not always the case, so it’s best to consult a professional to pinpoint the exact problem.

  1. AC Not Cooling Down Your Home

This case is similar to the previous one. In other words, AC can stop cooling down or turn off prematurely, before it shuts down completely.

What happens is – when the drain pipe gets clogged, the water has nowhere to go. This overflow can trigger the safety switch which then obstructs or stops the function of AC.

The one thing you can check here is if the condensation tray is full.

  1. Water Damage

Check the ceiling for stains around the indoor part of your AC unit. A yellow or brown stain is a very common sign of an obstructed drain pipe.

It goes without saying, but all that obstructed water has to leak somewhere. Even though it certainly doesn’t look pretty, at least it will warn you about something being wrong with your AC.

If this is the case for you, don’t worry, as the leak can be fixed, just like any other.

  1. Standing Water

As the water builds up due to the blockage in the system, your condensation tray will get full more often. Depending on your AC type, you might be able to see this.

Also, you may notice standing water anywhere around your AC unit. This is also a telltale sign that there is a blockage somewhere in the drain pipe.

Be sure to fix this problem as soon as possible as standing water can cause mold.

  1. Moldy Smell

The moldy smell around your house, especially when the AC is on, can indicate standing water inside the unit. This is because mold grows and thrives in a humid environment.

This kind of situation is certainly not pleasant, as you’re not only dealing with a bad smell. Be sure to not only fix the AC but also get rid of the mold as soon as possible.

Mold is known to cause many health problems, such as asthma, allergies, headaches, etc. [1]

  1. No Water Coming Out of AC Drain Pipe  

Finally, if there is no water coming out of the AC drain pipe, the pipe can be clogged. However, keep in mind that this is likely not the case if the AC is cooling the room just fine.

If you’re living in a very dry area, the condensated water can evaporate very quickly. This is also the case because the humidity indoors is limited.

In other words, the AC can condense humidity into the water only when the humidity is high enough. Make sure to check the weather conditions.

How To Unclog AC Drain Line 

If you have your AC drain line clogged, there are several different ways in which you can clean it. All of them require simple and easy steps.

In this part of the article, we will explain how you can unclog an AC drain pipe. After that, we will also explain how to clean it for maintenance.

How To Unclog AC Drain Line Without Bleach Or Vinegar 

Most of the cleaning solutions recommended for cleaning out the AC drain pipe are antimicrobial. This is because inside the AC unit there is most likely algae, mold, and other debris that needs to get cleaned.

Keep in mind that pouring down bleach or vinegar to an already clogged pipe might make matters worse. The cleaning solutions will improve the situation only if the clog is minor.

If the water is already backing up and causing problems, you should remove the clog manually, first.

To do so, follow these steps:

  • Turn off the power to your AC unit
  • Find the end of the drain pipe and remove the possible visible clog manually
  • Disconnect the drain pipe
  • Using the wet/dry vac, suck as much as the excess water and debris as you can
  • If this doesn’t help, try using a drain snake
  • Reconnect the drain pipe back to its place

Only after you finish removing the clog, you can move on to rinsing it with cleaning solutions.

But be careful – many are warning of the corrosive effect vinegar and bleach can have on metals. [3] While some would argue that vinegar is not as strong, many say that you should avoid pouring either of them.

This is important as the AC system has a part called an evaporator coil, serving to cool the air by removing moisture.

Using too many household cleaning solutions can damage this part of the AC system.

However, bleach and vinegar can still be used moderately to maintain the cleanliness of the drain pipe. Keep reading to find out how to do it properly.

Unclog Air Conditioner Drain Line With Bleach 


Cleaning with bleach comes down to timing and using it on proper materials. Using the bleach moderately on PVC pipes won’t damage them.

Nevertheless, make sure to remove the clog first. If you don’t you may be facing bleach residue which can cause even more damage. [4]

Bleach can’t unclog drains properly, so don’t use it for this purpose.

These next steps are to be followed after you’ve already turned the power off, disconnected the pipe, and removed the clog.

Make sure to use protective gloves and goggles when using bleach. Make a solution with bleach and hot water with a 50/50 ratio.

After disconnecting the drain line, pour the solution into it. Wipe any leftover debris on the outside of the unit as well.

If you’re not sure you got all the debris out before cleaning with bleach – then your case is an exception to this rule.

To be sure there is no bleach residue, you can wash with bleach while the AC is still operating. The condensation will remove all the possible bleach residue.

How To Clean AC Drain Line With Vinegar 


Cleaning with vinegar is fairly simple, and just as similar to cleaning with bleach. Use the same 50/50 ratio of hot water and white vinegar.

The next steps are the same, clean the condensation tray and drain pipe with this solution.

More people recommend using vinegar instead of bleach. Despite being acidic, vinegar won’t damage PVC pipes.

Using the white vinegar solution to clean the drain pipe regularly will get rid of bacteria, algae, and mold. Also, it can prevent their growth.

The Takeaway 

AC drain lines can get clogged easily with the changing weather and built-up debris. After carefully diagnosing the exact cause of the problem, one is able to easily fix it.

With the use of wet/dry vac or drain snake, the clog is removed. After that, the drain line is easily maintained clean with the use of vinegar or bleach.

Next time you get your AC drain line clogged, make sure to follow these steps to resolve the problem without worries.