If your home has a central air conditioning system, you may have noticed the AC drain line outside.

This pipe is located near the air conditioner’s condenser unit and it often drips water on the ground, so it’s hard to miss.

If you’ve ever wondered what’s with all the dripping, well, the drain line moves condensation from the inside air handler to the outside.

If this line clogs — and when it does, it’s usually because of algae — it can cause all kinds of problems. Like major water damage inside the house.

You can prevent a clog with simple, routine maintenance. Just pour a cup of household bleach into the AC drain line from the inside.

But once a clog forms, you can’t rely on the bleach method to do much of anything. So, attach a wet-dry vacuum to the drain line outside. (Remove the vacuum’s paper filter first.)

Then, turn on the wet-dry vacuum and suck the clog out of the pipe.

Tip: For regular condenser maintenance, clean the coils with Condenser Coil Cleaner. (This is an affiliate link. If you purchase this product, we will earn a small commission at no additional cost to you.)

Watch the video above to find out more.

Related: What is an Air Conditioner Vacuum Pump?

Further Information

Editorial Contributors
avatar for Joe Truini

Joe Truini

Radio Show Co-Host

Joe Truini is a contractor, author, and the host of “Simple Solutions” on Today’s Homeowner TV and the weekly Today’s Homeowner radio show. He has worked on both large commercial projects and residential remodeling, and has written for national publications such as This Old House and Popular Mechanics. He has also written eight books, including three best-selling shed-building books. Joe lives in Connecticut with his family and enjoys hiking, traveling, and baseball in his spare time.

Learn More