How To Keep Your Condensate Line Flowing Freely: Easy Steps To Clean & Clear A Clogged Condensate Drain Line

by Randy

Cleaning Tips, DIY, Heating And Cooling, Home Maintenance, Plumbing

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here's how to clean a condensate drain line and keep it clog-free

If you’ve got an air conditioner cooling your house, then you’ve got a condensate drain line leading out of your house somewhere — whether you know it or not.

And a clogged condensate drain line is not an unusual problem to have.

The drain line requires a little maintenance once or twice a year in order to avoid thousands of dollars in water damage repair bills. (Trust me, serious water damage can happen if you don’t stay on top of this simple annual task!)

Here are some signs of trouble with your condensate drain line.

Fortunately, it’s easy to keep your condensate drain line clear and clog-free.

I’m going to show you how to do it.

Gravity Flow Line vs. Condensate Pump

a/c condensate pump

First, you need to find out if you have a gravity flow line or a condensate pump (pictured here).

A gravity flow line will be a simple PVC pipe leading from your a/c unit’s evaporator coil.

I had a gravity condensate line with my old a/c system and always had water and algae growing across the shaded driveway. I used to save the water in a bucket and water plants with it.

Don’t laugh! It would fill a 5-gallon bucket on a warm day with no problem at all. I would even have overflow on really hot days — that’s when the algae would take hold in no time flat.

you can see the flexible tubing that connects to the gravity flow condensate drain line

When I had my new HVAC system installed back in 2005, I had the tech install an a/c condensate pump — in order to get the water to exit my house (through clear flexible tubing), up and over the cars in the garage, and connect to the gutter drain line where it exits my property through an underground drain.

That way, I’d never see it or worry about it again. It works like a charm, and I have one less headache!

You’re not here to hear about my system, though…

How To Clean The A/C Condensate Pump Or Condensate Line

If you want to clean and maintain your condensate drain line and/or condensate pump, there are a few ways to do it:

here the condensate drain line attaches to the a/c condensate pump

#1 – If you have a condensate pump (like I do), the service tech that installed my HVAC system told me to simply add 2 to 3 tablespoons of bleach to the pump reservoir once or twice a year while it is still in operation. The bleach/water mixture will eat up the algae and keep the line clear. That’s it!

Other websites state a similar process. For example, the WhisperKool a/c condensate pump kit comes with the following instructions to service and clean the condensate pump:

  1. Make certain that the unit is disconnected from the power source before attempting to service or remove any component.
  2. Be sure the floats move freely. Clean the floats as necessary.
  3. Clean the tank with warm water and mild soap.
  4. Check the inlet and outlet piping. Clean the inlet and outlet piping as necessary. Be sure there are no kinks in the line that would inhibit flow.

#2 – If you have a gravity flow line leading from your a/c unit, you can use a Shop Vac to suck out all of the gunk:

  1. Find the end of the drain line located somewhere outside of your home.
  2. Remove the filter from your Shop Vac (to avoid ruining it).
  3. Put the Shop Vac hose over the drain line, turn the vacuum on, and let it do its thing for a couple of minutes — as seen here.

#3 – If you have a clean-out (or a T) at the beginning of the drain line, do this:

  1. Open up the clean-out line (near your air handler, usually in the attic).
  2. Pour a warm water and bleach mixture through the condensate drain line — as seen here.

How To Clear A Clogged Condensate Drain Line

#1 – Use an air compressor.

Here’s how to do it:

  1. Open the clean-out pipe at the beginning of the condensate drain line.
  2. Stick the compressor air line inside.
  3. Blast away for a minute or two!

This will also do a fine job of cleaning the condensate line when it is especially cruddy.

#2 – Snake the drain line.

after fixing a clogged condensate drain line

This is usually a last resort to clear a clogged condensate line

You can rent a plumber’s snake or auger at your rent-a-tool center — just be sure that it will fit in your clean-out before you take it home. (Most drain lines are 3/4″ PVC.)

Terry Love’s Plumbing and Remodel DIY forum has some good tips on clearing a clogged condensate line.

The Bottom Line

You don’t have to hire an HVAC professional to clean or repair a clogged condensate drain line.

If you follow my simple tips above, you should be able to successfully clean and fix a clogged condensate line yourself.

Want to “see” all of the pieces and parts that I’m talking about? Here’s a video that describes most of the things I’ve mentioned, and has a few more suggestions on how to maintain your drain line.

And… if you’d like to see one more expert’s advice, the Tampa Bay Handyman shares more tips for cleaning a clogged condensate drain line.