How to Unclog an AC Drain Line

September 2, 2017

Precision | water dripping


The condensate drain line on your central AC unit does more to keep your unit running properly than you may think. If it’s clogged, you may have to worry about water backing up into your home, or worse. Thankfully, it’s fairly simple to unclog a drain line, and you can do it yourself in just a few minutes.

What Is the Condensate Drain Line?

The condensate drain line coming off of your AC lets the excess water drain from your unit — water caused by condensation when the hot air is passed over the cooling coils. Because the unit dehumidifies the air as it cools it, a significant amount of water may be produced over the course of the day. This water has to have somewhere to go, which is the purpose of the line.

What Happens When the Line Clogs?

A clogged line can cause serious headaches. First, the water backing up inside the unit may splash onto the coils, where it will freeze. This will stop your AC from working until the ice thaws out again.

The water could also back up out of the unit at the seams, which could flood the section of your home that the AC is installed in. And if it’s a slow leak that you don’t notice right away, you could also find a host of mold, mildew, or bacteria in the water. That’s why it’s so important to get the line unclogged as soon as you notice a problem, rather than just hoping that the problem is going to take care of itself.

How to Unclog the Line

There are essentially two ways to unclog the line: call a professional or do the job yourself.

When to Call a Professional

If you suspect that a clogged line is not the only problem, or it’s past time for your regular maintenance or tune-up, you may want to give a professional a call. Not only will a trained technician unclog your line, he will also flush it and check over the rest of the unit to discover any problems or issues that you may not have noticed yet. A good maintenance schedule can help prevent clogs from occuring, because a tune-up typically includes a line flush that gets out an algae or debris that could clog up the line over time.

Doing It Yourself

If you’re fairly certain that the only issue is a clogged line, and you have a wet/dry vacuum handy, there’s no reason why you can’t unclog the drain line yourself.

  1. First, locate the drain line on the exterior of your home. It will look like a piece of PVC plastic about a ¾ inch in diameter, coming from the side of your home near where the air conditioner is installed.
  2. Hook up the drain line to your wet/dry vac, and make sure that you get a good seal between the drain and the vacuum. Without a good seal, the vacuum won’t be able to affectively pull the clog out of the drain.
  3. Turn on your vacuum and let it run for about three minutes. This should pull the clog out of the drain, as well as anything else that was built up inside, such as algae, dirt, and stagnant water.
  4. After three minutes, turn off the vacuum and take a look inside. You should be able to see what you pulled out of the line. If you don’t find the clog you expected, give a call to a professional to come by and make sure that nothing else is going on that could mimic a clog.

Keep Your Drain Lines Clear

Keeping your condensate drain line clear is a crucial part of making sure your AC unit runs efficiently all summer long. Consider a regular tune-up to keep it from getting clogged, and make sure that you take care of clogs as soon as you find them, either by removing them yourself, or calling in a professional. Don’t wait until you have a serious water problem on your hands, and keep your AC running in top condition all summer.