How to Unclog and Clean Your AC Drain Lines Thoroughly

Josh Mitchell

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Josh Mitchell

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Holly Curell

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Cleaning the drain line is one of the most overlooked aspects of maintaining an air conditioner.

I find that many people overlook a clogged pipe because it doesn't affect cooling.

Cleaning out the line will keep water flowing and prevent damage to your home. Here, I'll outline easy ways you can do it yourself.

9 Methods For Cleaning AC Drain Line

These are my top nine best methods for cleaning an air conditioner drain line.

Keep in mind that each method may not work for your AC system's drain layout.

Additionally, I've put the methods in order from easiest to most complex, with some requiring special tools.

1. Flushing Clean Water Through It

First, I try to flush clean water through your AC lines. The water that flows through an AC’s drain line is not pressured.

I’ve managed to clean an AC drain line that was clogged around the edges with just water.

I like to use a water hose, but it requires a second person or a good hose nozzle to turn the water on and off. Then, I carefully flush the pipe until the water is flowing freely.

However, this will only work for a partially plugged pipe, and you will need to have room to pour water directly into the pipe.

Useful Tip:

Whatever you do, don’t add dish soap to the pipe because it will make a big, bubbly mess.

TL;DR: Flushing water down the drain line is the first line of action.

2. Using Chemical Drain Cleaners

Stubborn clogs require a little more power than just fresh water, which is where chemicals come into play.

Commercially available drain cleaners like Drano and Mr. Plumber offer a good option for removing a blockage.

I don’t recommend drain cleaners for breaking up clogs in your main drains simply because they rarely work.

However, I have had decent success in using them for AC drains.

If you use a drain cleaner, pour it directly into the drain pipe.

Also, follow the step-by-step guide on the bottle and wear protective gloves and safety glasses.

TL;DR: You can try out specialized chemical drain line cleaners. However, just know that they often do not work.

3. Pouring One Cup of Distilled Vinegar Down the Drain Line

A more holistic and natural alternative to commercial drain cleaner is a cup of distilled vinegar and baking soda.

This is actually a great place to start if you already have the necessary ingredients.

This didn’t make it higher on the list because it is less likely to work. I pour a few cups of hot water down the drain, followed by a cup of vinegar and a half cup of baking soda.

Let the solution sit for about twenty minutes, then try using a plunger if the water still won't go down.

TL;DR: You can create a DIY chemical drain cleaner using vinegar and baking soda. This can work if the clog isn't too stubborn.

4. Pouring One Cup of Bleach Down the Drain Line

Bleach is a great way to clean out a drain filled with slime or algae, and I like to pour some down the drain at least once a year to keep the line clear.

However, it also works to clean a blocked pipe. To clean a drain, I pour about one cup of bleach down and let it sit.

Important Tip:

Before I go into more detail, do not pour bleach down the drain if you’ve already poured vinegar or vice versa. Mixing the two ingredients creates a toxic gas.[1]

This is my method of choice for lines that are not completely clogged.

TL;DR: For partial drain line clogs, a cup of bleach is an excellent method to clean it.

5. Using a Wet/Dry Vacuum

Another of my go-to methods is using a shop vac to suck the water, and gunk, out of the condensate drain line.

You must use a wet/dry vacuum designed to pick up water, not your household vacuum cleaner.

Start by using the shop vac to suck out the water in the condensate drain pan. Then, put the shop vac hose to the drain line to vacuum out the blockage.

For this to work, you must have a good seal between the vacuum hose and the drain line.

I sometimes use duct tape to create a good connection to the clogged condensate drain line.

TL;DR: This is fairly safe way to clean the AC drain line, however, its not as accessible since not everyone has a shop vac lying around.

6. The Plunger Method

Next, I would try the plunger method, but it won’t work for everyone. It requires a special plunger that can fit on the small condensate drain line.

These are often called power plungers, AC drain suckers, or hand plungers.

Instead of using a stick like a conventional plunger, a handheld pump moves air up and down to break up the clog.

I don’t recommend this method for homeowners because it does require you to cut the condensate drain pipe open.

However, if you don’t mind cutting the condensate line, this is a good way to break up a stubborn clog.

TL;DR: AC drain line plungers are a small specialized tools that work line normal plungers, but do require you to cut the condensate pipe.

7. Blowing Air Through the Line

Blowing out clogged AC drain lines is usually done by a professional HVAC technician.

They will cut the line open and use a tool that blasts air into the air conditioner’s drain line to clear it out.

There is also a tool called a Gallo Gun that fits inside the unit’s clean-out Tee, so they don’t have to cut the line open.[2]

This is similar to the plunger method but more likely to dislodge a stubborn clog. I've also seen people blow into the drain line with a small air compressor.

The problem is that blowing air through the line only works on a completely clogged condensate drain line. It will not help on a partially clogged AC drain line.

TL;DR: Using pressurized air, you can blow stubborn clogs. You can find tools like Gallo Gun to blast air through the drain line.

8. Using an Electric Snake

In worst-case scenarios, you may have to call an air conditioning company to use an electric snake.

They will run a metal snake down the condensate drain line to break up and remove the clog.

This is a guaranteed way to remove blockages. However, it may not remove organic matter stuck to the sides of the pipe.

Using an electric snake is pretty rare because the line is so small, but some condensate lines enter the home’s main sewerage lines, which is where an electric snake really comes in handy.

TL;DR: An electric snake is one of the best ways to remove blockages, but it does require that you procure the special tool and also some skill in using it.

9. Replace the Drain Pipe

Sometimes, a drain line is clogged so badly that the only option is to replace it entirely.

Most drain lines are PVC pipe, which is very easy to replace as long as it is accessible.

Look around the outside of the house to see where the condensation line comes out. As long as the path from the air handler to the outside of the home is pretty straight,

I would replace the entire thing rather than waste time cleaning out a cheap piece of pipe.

TL;DR: When all else fails, replacing the drain line is the only viable solution.


Why Bother Maintaining the Drain Line At All?

Keeping an AC drain line clear is critical because a water backup can wreak havoc on your home.

A common misconception is that water backing up will only affect the air conditioning system, but it can also lead to water damage in your home.

The evaporator coil of an AC builds up moisture as warm, humid air passes over the cold coils and creates condensation.

A drain line then removes this water from the AC system.

However, the slow-moving water is a breeding ground for algae growth, which can clog up the system.

A clogged AC drain line will start by backing up into the drain pan. This standing water leads to musty odors and even mold growth in your home.

Backed-up water can eventually overflow and run across the ceiling and down walls, ruining Sheetrock and even flooring, quickly leading to thousands in repair bills.

TL;DR: A clogged drain line and overflowing drain pain can be a breeding ground for diseases and fungi and can also deteriorate your home's structure over time.


Signs and Symptoms of a Blockage

Most people only realize their AC's drain line is clogged once excess water overflows the drain pan.[3]

Fortunately, most air conditioning systems have a secondary condensate pan under the evaporator coils.

If excess moisture is detected, this pan should have a safety feature that shuts off the indoor evaporator coil.

Here are a few of the common signs that you have a blockage:

  • No power to the thermostat or indoor air handler
  • A musty or moldy smell around your air conditioning system
  • Standing water on the floor or moisture on the walls and ceiling near the air conditioning unit
  • Water coming out of the secondary drain line

Important Tip:

If you suspect a drain line is clogged, you must act quickly to prevent further damage by shutting off power to the indoor and outdoor unit.


How to Prevent Congestions in the First Place?

  • Use High-Quality Air Filters:
    Using a good air filter (MERV 5 or higher) ensures that dirt and other particles can’t get to the drain pan and clog the condensate line.[4]
  • Flush the Drain Line Regularly:
    Flushing the drain line with water and a cup of bleach is an easy method to clean the sides of the drain line.
  • Clean the AC Unit Thoroughly:
    Cleaning out the evaporator coil is another way to ensure that dirt and grime never make it to the condensate drain.
  • Opt for Routine Maintenance:
    Air conditioners require regular cleaning, so it is a good idea to have your entire system serviced annually.

Call An Expert When Simple Methods Fail

If you can’t get your air conditioner’s condensate line unclogged, it’s time to have a professional HVAC technician clean your AC.

They will identify the cause of the clog, break it up, and remove any remaining debris and dirt from the line and condensate pan.

An HVAC technician can also offer guidance on what maintenance should be performed on a regular basis.

Many companies offer a maintenance plan, where they will come out regularly to clean out the system, check for a dirty filter, and ensure the system is running at peak performance.


People Also Ask (FAQs)

How Much Does It Cost For An HVAC Professional To Unclog An AC Drain Line?

The cost for an HVAC professional to clean your AC system depends on a couple of factors. But the primary one is how much time it takes.

Expect to spend a minimum of $100-$150. Expect to pay more if the access point makes it difficult to get to the system.

How Often Should The AC Drain Line Be Cleaned?

You must clean the AC drain line regularly to prevent clogs. I recommend having your AC system serviced once per year.

It is best to have this done in the Spring to ensure the cooling system runs at peak performance before the hot Summer months.

Can A Clogged Drain Line Turn Off My AC?

A clogged drain line may lead to condensation backing up into the evaporator coil.

Most new units have moisture sensors on the air handler or drain pan, which can shut the air conditioner off to prevent water damage in your house.

References: 

  1. https://sciencestruck.com/what-happens-when-you-mix-vinegar-bleach
  2. https://www.nucalgon.com/media/8229/3-160_galloguncannon.pdf
  3. https://www.carrier.com/residential/en/us/products/air-conditioners/air-conditioner-maintenance/clogged-ac-drain-line/
  4. https://www.epa.gov/indoor-air-quality-iaq/what-merv-rating
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Josh Mitchell

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Josh Mitchell
My name is Josh and I am obsessed with home appliances. From portable AC units to heaters and air purifiers, I enjoy testing, learning and using these devices to improve the air quality inside my family home.

My Favorite Home Appliance?

Midea U Shaped Window Air Conditioner

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