My Air Conditioner’s Drain Line is Clogged. What Do I Do?

If your AC drain line is clogged, it’s most likely due to an excess build-up of dirt or algae somewhere in your drainage line.

In Arizona, we usually see clogged AC drain lines during or right after the Monsoon season because there’s a lot of dust and debris being blown around, which can easily get into the drain line and cause a clog.

However, a clogged drain line is not always the result of storms. Below, we’ll go into more detail about how your AC drain line can get clogged and we’ll provide you with some information on how to unclog your AC drain line.

As we mentioned above, your drain line can become clogged when excess dirt or other debris make their way into your drain line.

Your line could also be clogged if there is mold or mildew growing in your drain line. The AC condensate drain is designed to drain moisture your AC collects outdoors (see image below). That said, this line is constantly damp, dark and dirty—the perfect conditions for mold and mildew growth.

To recap…

If it has been storming recently and your AC drain line is clogged, it’s probably due to dust and debris that has made its way into your drain line and clogged it.

If it hasn’t been storming recently, your drain line is probably clogged by mold or mildew growth.

Now that you know the potential cause of your drain line clog, let’s look at ways you can unclog your drain line.

Before we go into the details of how to unclog your drain line, we want to warn you that if you’re experiencing the following “symptoms,” you should not attempt to unclog your condensate drain yourself and you should instead call a professional ASAP.

Don't attempt to unclog the drain yourself if:

• Your AC has shut off and isn't working
• You see water leaking around your indoor unit"/"your notice water stains from AC
• You notice that your ceiling is stained

However, if you notice a small amount of water around your indoor AC unit and your house feels a little warmer or muggier than usual, it’s probably okay to try to unclog your condensate drain line yourself.

Follow these steps to unclog your drain line:

Step 1: Turn your AC off. You can do this from your thermostat by turning your system from COOL to OFF.

Step 2: Go outside and try to create an airtight connection between your shop vac and your condensate drain line. If you aren’t sure how to create a tight connection, you can use your hands, duct tape or tightly wrap a towel around the connection.

Note: if you’re having trouble finding your outdoor condensate drain line, it should look something like this:

Step 3: Once you’ve created a good connection, turn on the shop vac for 1-2 minutes.

Step 4: Check the shop vac to see if anything was pulled out of the condensate line. If not, the clog may be too high in the drain line and you may need a professional to come break up the clog for you.

Step 5: Turn your AC back on. If you don’t notice any new indoor water leaks near your AC system and you DO notice a small amount of water or drainage coming from your condensate drain line, you should be good to go!

If you are having trouble unclogging your drain line this way, you can also try using a garden hose.

Here’s how it works:

Step 1: Connect your garden hose to the end of your condensate drain. You’ll want to make sure you create a seal around the hose/drain connection by placing your hand around the connection. This will provide a stronger burst of water when you turn the hose on.

Step 2: Turn on the hose for 5 seconds then turn it off. These short spurts of water will usually help to break up any clogs inside the drain.

Step 3: Repeat step 2. Continue to repeat step 2 until there is no longer dirt/debris coming out of your condensate drain.

If you don’t feel comfortable unclogging your own drain line or your drain line is still clogged after you’ve tried the steps listed above, it’s time to contact a professional.

To prevent a clogged line going forward, you should:

1. Have your drain line and AC system cleaned by a professional at least once a year. Note: If there is a strong monsoon and/or dust storm season, you should schedule an additional coil cleaning to combat any dirt trying to make its way into the system.
2. Change your home's air filter every 30-60 days. This will prevent any excess dust from finding its way into your system from the inside of your home.