How to Clean Your Air Conditioner Drain Line with One Household Cleaner

Your condensate drain line keeps moisture from building up inside your air conditioner. But, there’s always the potential for mold, mildew, and algae to develop. Thankfully, you can clean the line with one household cleaner that you may already have on hand—distilled white vinegar. All it takes is this one ingredient to take your drain line from clogged and slow to running smoothly.

What is a condensate drain line?

Your air conditioner does more than cool your home. It’s also responsible for removing heat and moisture from the air, dehumidifying it in the process. All that moisture turns into condensation, and it has to go somewhere, which is where the condensate drain line comes in.

Your air conditioner has a condensate drain line that runs from the indoor unit to the outside of your home. Most condensate drain lines use gravity as their main mechanism, however some may use a small pump to expedite the drainage process.

How to clean your drain line

Before cleaning the drain line, you need to make sure to turn off your air conditioner. First, power down your thermostat. Then, locate your home’s circuit breaker box and flip the switch to turn off the air conditioner. After the power is off, it only takes a few steps to give your drain line a thorough cleaning.

Step 1: Locate the drain line

You’ll find a white PVC or copper pipe located near your outdoor unit; this is where the drain line ends. Near your indoor unit, you’ll find a vertical PVC pipe with a cap on it, which acts as the access point for the condensate drain. Remove the cap to access the drain and to check and see if there are any visible clogs or blockages.

Step 2: Clear clogs

Over time, a sludgy blockage can develop in the drain line and ultimately cause a complete clog. If you’ve ever noticed water backing up into the AC drain pain, a clog is likely to blame. A clogged drain line also provides the perfect breeding ground for bacteria, mold, and algae. The bottom line is, you’ll want to clear clogs before cleaning the drain.

Clearing clogs before cleaning the drain ensures that the vinegar will be able to reach the entire drain. There are two methods you can use to clear clogs with ease.

Wet/dry vacuum

A wet/dry vacuum can be used to remove any clogs in your drain line with the power of suction. You can rent one from most hardware or grocery stores. If your drain line clogs frequently, it may be a good idea to invest in one to have on hand. After turning off your air conditioner, locate your drain line runoff—the white PVC or copper pipe attached to the exterior of your home. Then, follow the these steps to use the wet/dry vacuum to remove the clog:

  1. Attach the vacuum hose to the end of the drain line. Make sure you have an airtight seal. You can secure a cloth towel or duct tape around the opening of the drain line to make sure there are no gaps between the vacuum hose and the drain line.
  2. Run the vacuum for 1-2 minutes.
  3. Open the vacuum and see if you’ve removed the clog. If you see a lot of brown-colored water, or some algae buildup, you likely removed the clog.
  4. If the vacuum is empty, repeat step 2 as needed. If the clog does not clear after several attempts, you may have a severe clog that needs to be cleared by a professional.

Garden hose

If you don’t have a wet/dry vacuum, a garden hose can also sometimes be used to break up clogs with water pressure. The force of the water running through the drain can force the algae buildup out of it. Follow these steps to make this method work:

  1. Connect the head of the garden hose to the opening of the condensate drain.
  2. Maintain a tight connection between the drain and the hose with your hand and run the hose on high in short bursts. This should allow the water to travel upwards and break up any clogs in the drain.
  3. Repeat step 2 until the water runs clear.

Step 3: Use white vinegar to flush the line

Remove the cap on top of the tube and pour ¼ cup of vinegar down the drain line. To avoid spilling the vinegar, you can use a funnel. The vinegar will get to work, killing bacteria and breaking down any leftover buildup. You can also add hot water and a bit of dish soap for enhanced cleaning power.

Step 4: Turn the power back on

Make sure to wait 30 minutes before turning your air conditioner back on. If it’s been a long time since your drain line was cleaned, opt to wait for a whole hour.

Step 5: Repeat every month for a continuous clean

To prevent bacteria and sludge buildup, it’s best to repeat this drain-line cleaning routine at least every month or two. That way, the drain will stay in good working order and avoid clogs, while keeping mold and algae at bay.

Cleaning your condensate drain line isn’t the only thing you can do regularly to keep your air conditioner in good working order. Other easy tasks include:

  • Changing your filters every 30 days
  • Vacuuming dirt, dust, and debris from the exterior fins of your outdoor unit
  • Keeping plants and weeds from growing around the base or sides of the outdoor unit
  • Look out for common problems and signs that it’s time for a repair or replacement
  • Scheduling annual maintenance visits in the fall and spring

Chas Roberts knows air conditioners, inside and out

From condensate drain lines to compressors, coils, and all the nuts and bots that make your air conditioner tick, Chas Roberts knows HVAC systems inside and out. Trust our experienced professionals to get the job done and our tradition of strong customer service to make the process easy for you. Contact us to get started.