Step By Step: How To Unclog Your AC’s Drain Line

Airconditioning units will sometimes need some simple maintenance to keep them running smooth and efficiently.  Much of the maintenance of your AC system can be avoided by keeping the air filter clean and replacing it regularly.  In warm climates, the humidity can allow for mold and slime to build up in your system.  This will require additional support by unclogging the system’s drain line.  The drain line allows for built up moisture to run off to the exterior of your home.  Your AC drain line sometimes will get clogged up and needs to be flushed out.  You can clean this drain line in a few simple steps using standard household products.
You will want to make sure to turn off your system by switching off the main breaker in the breaker box of your home.  This is a safety precaution that should be adhered to as you are working around electrical components and will be dealing with water, two things that do not mix.
The first tool you will need is a long hose.  Bring the hose to the AC system in the interior of your home.  Next, locate the drain line on your system.  This will either be a flexible tube or a PVC pipe on the bottom of the system, underneath the drain pan.  If your line is clogged the drain pain will more than likely be filled with water, so be careful working around it.  You will want to avoid spilling this water in your home and causing issues with wet carpet and mold.
Flush and Bleach:
This will be a two man job because you will need another person to locate the drain pipe on the exterior of your home.  It will be closely located to the fan that’s installed near one of the walls of your home.  This person will need to check when water begins to flow out of the drain pipe and identify that the line has become unclogged.  The source of clogging will be from algae build up in the line.
This simplest way to unclog it will be to use the hose you brought in, attach it to the drain pipe to force the build-up out of the line.  The person on the outside of your home will need to turn on the hose once you have hooked it up to the drain pipe.
After you have flushed out any particles that have clogged the line, you will want to kill any algae and mold that has built up in the line.  You can do this using a simple bleach and water mixture to disinfect and kill the slime buildup.  A good ratio to use is one part bleach to sixteen parts water.  Just pour the mixture into the drain line at the same location you attached the hose.  If you still have a clogged line and there is no water flowing out of the pipe, you may need to use a wet-dry vacuum to remove whatever is inside.  The key is to create pressure in the line to remove anything inside.
If water pressure does not do the trick, use a bleach solution to try and kill and dissolve particles inside the line.  As a last ditch effort, if water pressure does not work, bleach doesn’t work, and suction from the vacuum is not working, then you will need to create pressure using compressed air.  Nitrogen or CO2 will be sufficient, but this can cause a mess and will need to be cleaned afterwards.  If you get all the way to using compressed air, make sure to clean the line with a bleach solution later to make sure the line is free of any residue.
Cleaning your AC drain line can be very simple or can take a few steps depending on how badly it is clogged.  Make sure to use care and patience when attempting to clean the line so that you do not damage any of the equipment.  Most important is to make sure that the circuit breaker is turned off before working on the system.
Nick Quinlan is an Orlando resident and do-it-yourselfer who likes to find ways to fix any problems that may be going on around the house. For air conditioner problems he can’t solve however, he pays a visit to You can learn more about Nick by visiting Google+.

Leave a Comment