How to Clean Your AC Drain Line With Vinegar

How to Clean Your AC Drain Line With Vinegar

how to clean ac drain line with vinegarWhen cleaning their homes, most homeowners dust, vacuum, sweep, and mop, but many neglect to regularly clean a vital part of their home comfort: the AC drain line.

Although it may not seem like a problem, your AC drain line produces condensation, and when your AC drain line is not cleaned regularly, it can become a spawning ground for algae, mold, and other bacteria. These bacteria can build up and slowly clog your AC drain line over time, causing your AC system to function inefficiently, and if the clog gets big enough, it to not work at all.

All central AC systems should have a float switch that turns off the AC unit when the drain line fills with water and begins to leak. This switch’s primary function is to prevent water from overflowing and damaging floors or other parts of your home. Until that water clears, the system will not turn on.

When the excess condensation cannot escape through the drain, water can leak from the AC unit and cause substantial water damage to your home.

It’s best to have your entire AC system regularly maintained by a professional, but cleaning your AC drain line is a maintenance task you can easily do yourself.

Is Bleach or Vinegar Better for Your AC Drain Line?

We recommend using vinegar instead of a bleach solution because bleach can be harmful to your AC system if your drain line has copper tubing. Using vinegar will not damage your system.

Spilling bleach can also ruin carpet or clothing, whereas vinegar will just leave a strong odor.

How to Clean An AC Drain Line With Vinegar in 6 Steps

Cleaning your AC drain line is an important task that should be done regularly to prevent water damage and mold growth in your home. By following these steps and using the materials listed, you can clean your AC drain line quickly and effectively. Remember to monitor the drain line and clean it as needed to ensure it functions properly.

One of the most efficient ways to clean your AC drain line is by flushing it with vinegar. By pouring a cup of vinegar down your AC drain line, you kill the algae, mold, and other bacteria that can build up and cause clogs.


  • 1 cup of vinegar
  • 1 cup of warm water (optional)
  • Funnel (optional)
  • Rags, washcloths, or paper towels


Follow these step-by-step directions and learn how to quickly and safely clean your AC drain line, allowing your AC system to operate at maximum efficiency.

Step 1. Locate the AC drain line.

The first step in cleaning your AC drain line is locating it, which may not always be easy. The entry to your AC drain line is a white, T-shaped PVC tube, generally located inside a utility closet or your garage, but in some cases, it can be in the attic. Depending on your specific AC system, it might be hidden behind a removable access panel. The drain line typically exits near the outdoor unit of your AC system and is a small, white plastic pipe that runs from the AC unit to the outside of your home.

Step 2. Turn off the power to your AC.

Before doing any work, turn off your AC system at the thermostat and the breaker or disconnect/shut-off box to be safe.

Step 3. Remove the cap or drain line cover

After you find the drain line, locate the access point, which should be a white plastic cap on top of the T-shaped PVC tube. You should be able to gently remove it by hand.

Step 4. Flush the drain line with vinegar.

Slowly pour a cup of vinegar down your AC drain line. Using a funnel here is optional and will reduce your chances of spilling the vinegar. Don’t forget to put the cap back on when you’re done.

Step 5. Wait.

Wait 30 minutes to an hour before turning your AC back on. The vinegar will kill the bacteria, but it may take some time to work, especially if you have not cleaned your AC drain line in a few years or had a professional perform maintenance on your AC system. If you notice water overflowing or a musty smell in your home, it is likely that the drain line is clogged and needs to be cleaned again.

Optional: You can pour a cup of warm water down your AC drain line to help flush out any bacteria build-up or to remove the vinegar odor.

Step 6. Turn the Power Back On

Once the cover is securely in place, turn the power back on to your AC unit.

How Often Should You Put Vinegar in Your Air Conditioner?

For the best results and to keep your AC drain line clear, you’ll want to repeat this cleaning routine monthly or at least every other month. This will eliminate any algae, mold, or other bacteria or sludge buildup in your AC drain line and prevent your drain line from clogging up.

30 Replies to “How to Clean Your AC Drain Line With Vinegar”

    1. Hi Michael, that’s a great question and I’ve updated the article to provide more information around that.

      You do not need to add water with the vinegar and it’s better if you don’t. However, you can pour a cup of warm water down your AC drain line about 30 minutes after the vinegar to help flush out any bacteria build-up or to remove the vinegar odor, but adding vinegar alone is all you need to clean it.

    1. Hi John,

      I wouldn’t recommend attaching the shopvac to the top of the line unless you have to. Clogs generally don’t form at the top of the line and you’ll be going against gravity. Also, the water the shopvac sucks out is going to be grimy and gross. You don’t want to risk spilling this water inside your home. It’d be much better to attach the shopvac to the bottom and dispose of the water outside.

      For more information, check out our guide for unclogging an AC drain line here:

  1. I have read different amounts of vinegar from 1/4 cup, 1/2 cup to 1 cup… it is confusing… will it Hurt to use more or less?

    1. Hi Ruth,

      You won’t hurt your AC drain line by pouring too much or too little vinegar. However, the more vinegar you use the more effective the cleaning will be, which is why we suggest a cup, especially if you live in a humid climate that promotes mold and mildew growth.

      If you suspect your drain line is clogged, depending on where the clog is, you could overfill the drain line by pouring too much vinegar, but that should not cause any damage to your system, only a small mess.

      Instead of pouring vinegar into a clogged AC drain line, check out our step by step directions to unclogging an AC drain line here:

    1. Hi Ruth,

      Yes. You’ll want to wait 30 minutes to an hour to allow the vinegar to kill the bacteria before turning the AC back on. I’ve updated the article to clarify this, thank you for your question.

    1. I messed up. I poured a small bottle ( 4 cups) of vinegar into drain line. AC was shut off. I so the lumps of dirt flow out. You think I damaged coils or something?

      1. Sounds like the vinegar did its job and cleared some grime from your drain line. I think it’s unlikely you damaged the coils or another part, but I’d monitor the situation and maybe call a professional to diagnose any issues if you’re worried.

  2. I’ve been doing this for some time but continually have to clean the pump every 6 months or so due to buildup, is there some other way to prevent this issue?

    1. Hi Alfredo,

      Your AC drain line is a white, T-shaped PVC tube that’s generally located inside a utility closet or your garage, but in some cases, it will be in the attic. Depending on your AC system, it might be hidden by a removable access panel.

  3. Mine is located in the attic, but there’s a clear tube that dips and goes up, very close to where i pour the vinegar. I noticed half of the vinegar got stuck there so I waited 30 min then poured a cup of water to push the vinegar out of there. Will that water now sitting in that clear tube cause any issues? Thank you for your help and time.

  4. Hi,
    Great article, thank you for this information. I just completed this process remembering what i learned a while back. I just finished but didn’t turn the AC off during the process. Will this make a difference? Or is it just a precautionary measure? Thanks again!

    1. Hi Kris,

      Yes, this is more of a precautionary measure. Anytime you perform maintenance on your AC system you’ll want to turn it off to reduce the risk of any damage to the system, and of course, to prevent any injury to yourself.

      When cleaning your AC drain line, if you pour vinegar into a clogged drain line it’s possible to overfill and the vinegar can flow back into your AC.

      Unless you’re experiencing issues with your AC now, it probably won’t make a difference in your instance, but I’d suggest turning off your AC in the future when you repeat this process.

  5. Ps: I know the AC guy had poured like a bottle of some fluid in there. It looked soapy. I touched it coming out. So it felt soapy. I poured a lot of vinegar in after a month. Soapy white jell like clumps came out. Sigh.
    It seems it’s clean now. But did I damage something with pouring in a lot of vinegar?

    1. Some HVAC technicians use a special formula to clean AC drain lines, that’s probably what was in the bottle. Not sure what the soapy white jell like clumps were, it’s possible the cleaning solution did that and there’s nothing to worry about. It’s unlikely you damaged anything by pouring in a lot of vinegar. As long as your AC was off and the vinegar drained without pooling, your AC system should be fine.

    1. Hopefully your AC was off when you did that! The float switch can sometimes be the access point for AC drain lines, so as long as there wasn’t a clog towards the entry point causing water to overflow back into your AC system, there shouldn’t be any damage to your system or home. This is why step 1 is to turn off your air conditioner.

  6. Hi my a/c is located at my bedroom can i also use vinegar to spray it directly to the evaporator during cleaning because dirt became gummy gels & molds were formed from all over the evaporator. Thanks & God bless

  7. Can I clean a split-type air conditioner drain with vinegar or will the vinegar harm the delicate aluminum fins on the evaporator coils (the ones inside the house).?? Don’t want to take it apart but wondering if I could pour a little vinegar down the coils so it could clean out inside the drain pan.

  8. I have a heat pump which heats in winter and is air conditioner in summer. I have been told to mix 1/2 cup vinegar with a gallon of water and flush once a month only in the summer. Is this right?

  9. I have an EZ trap installed with the clear u-shaped trap. Is it still recommended to clean the drain line with vinegar? Also do I pop open the float switch cap and pour down that opening?

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