What is the white stuff in AC drain line?

Author: Pink Pollich  |  Last update: Sunday, September 21, 2025

Before you panic, rest assured that white slime isn't uncommon. It's a biofilm composed mainly of bacteria called Zooglea. Zooglea forms a protective layer around itself, thriving in the dark, damp environment of your AC's drain pan.

How do I get rid of white slime in my AC drain line?

- Pour about 1 cup of distilled vinegar or a mixture of bleach and water (1:1 ratio) into the drain line. This will help eliminate mold and algae. - Let it sit for at least 30 minutes. Rinse the Line: After letting the vinegar or bleach solution sit, flush the line with water.

What is the white sludge in drain pipes?

Minerals refer to limescale or calcium buildup in drains, pipes, or plumbing fixtures. The buildup can occur in shower drains for example due to the sodium, magnesium, and other chemicals found in hard water.

What is the sludge in my AC drain line?

The gross white slime you're seeing in your AC drain line is most likely a combination of mold, mildew, algae, and other organic matter. This phenomenon is quite common in air conditioning systems, particularly in warm and humid climates like ours here in Central Florida.

What is the gunk in my condensate line?

Over time, sludge and buildup form in your condensate drain line. This debris can include mold and mildew, algae, bacteria, fungus and even small plants. Once enough buildup accrues, the blockage will become too large and create a clog in the line, causing water to back up into the AC drain pan.

How to Clean Your AC Condensate Drain Line

How do you dissolve gunk in AC drain line?

Pour One Cup of Bleach Down the Drain Line

It will kill any bacteria or mold present in your drain line, just like vinegar will. Pour one cup of bleach down your drain line every month to help keep it free from clogs. One cup of bleach is the cheapest and easiest way to unclog the drain line in your AC.

How often should I flush my AC drain line?

Clean your AC drain line every one to three months, depending on its tendency to clog. For example, if you live in a particularly humid area that's prone to algae and mold growth, have an old home, or have several furry pets, clean your AC drain line as often as once a month.

What is the white stuff in my AC drain?

Before you panic, rest assured that white slime isn't uncommon. It's a biofilm composed mainly of bacteria called Zooglea. Zooglea forms a protective layer around itself, thriving in the dark, damp environment of your AC's drain pan.

How do I stop sludge in my drain pipes?

DIY Drain Maintenance
  1. Keep large food scraps and hair out of your drain pipes by installing a screen over your drain.
  2. Once a week, run hot, boiling water down the drain for several minutes to flush out films.
  3. Never rinse grease down the drain.
  4. Regularly clean your drain and sink stopper.
  5. Plunge your drain when needed.

Is bleach or vinegar better for an AC drain line?

All right, so in summary, don't use bleach; use vinegar. That helps with any mildew growth—keeps you running clean. It's not going to actually clean your A/C drain, but it can prevent some backups.

Why does my AC condensation line keep clogging?

Another common cause of clogged AC drain lines is excess dust or debris in the AC system. Dirty AC filters and coils can allow dust to get into the drain line. Periodically flushing the drain line with water can help keep the line clean.

What are the white chunks in my drain?

Answer: Hard Water

That white buildup that often encrusts the surfaces of your fixtures is calcite residue from hard water. You may have heard about hard water before without properly understanding what it means. Hard water generally refers to any water with a high mineral content.

What is the best cleaner for AC drain line?

Water and Dish Soap

Dish soap and water, of course! Use a mixture of both to clean your AC drain line. The dish soap will help to break down the dirt and debris, while the water will flush it away.

What kills AC slime?

Here is what you should do to get rid of the slime:
  • Remove the Air Filter. First, remove the air filter. ...
  • Vacuum Bacteria and Debris. Next, with the air filter gone, you can work on cleaning out the bacteria from the entire system. ...
  • Clean Bacteria With Bleach. ...
  • Clean Coil and Replace Air Filter.

What is the white stuff blowing out of my AC?

AC Condensation Accumulating In The Heater Box

As a result of this process, condensation is produced. When moisture builds up in the heater box, it may eventually turn into vapor and get released with the cooled air, so you see white smoke coming from the air conditioner vents.

What dissolves slime in drain pipes?

Begin by pouring up to a whole box of baking soda down the drain, depending on the severity of the slime. Then pour in the vinegar, up to half a bottle. You should hear or see the fizzing. Let it react for about five minutes, then slowly pour the boiling water down the drain.

How do you get rid of sludge?

There are a few different methods for removing sludge, including gravity thickening, aerated stabilization, and centrifugation, among others. Gravity thickening involves using gravity to separate the sludge from the water, which can be done in large tanks or basins.

How do you flush sediment out of pipes?

Begin the flushing procedure by opening the hot water taps in your bathroom(s). Open ALL hot water sink fixtures, hot water bathtub or shower fixtures. Next, open all other hot water fixtures, such as in kitchens, wet bars, etc. Run all of these hot water fixtures for 15 minutes, then shut the water off.

How to get rid of white slime in AC drain line?

You can use a wet/dry vacuum to remove the slime and other debris, and you can finish the job by flushing the line with a cleaning solution. Cleaning or replacing your AC filters regularly and having a pro clean your evaporator coils may stop AC drain slime from happening.

What kills white slime?

The condensate drain line is a prime location for white slime accumulation. Ensure this line is clear by flushing it with a mixture of bleach and water every few months. This will help to kill bacteria and prevent biofilm formation.

How do you remove gunk from AC drain line?

Just Mix a cup of hydrogen peroxide with a tablespoon of baking soda. Pour this mixture down your drain and let it foam. This should help to break up the clog and clear your drain.

What happens if you don't clean your AC drain line?

If the drain line gets blocked, you may experience reduced cooling efficiency, water leakage, frozen coils, Mold and mildew growth, and even a shutdown of your entire air conditioning system.

Is vinegar or bleach better for AC drain line?

Cleaning AC Drain Line

We recommend using vinegar instead of a bleach solution because bleach can cause corrosion if you have copper tubing in your AC's drain line. In addition, spilling bleach can ruin your carpet or clothing, whereas vinegar does not harm; it just leaves an odor.

How to keep AC drain line clear?

BEST PRACTICES TO KEEP YOUR AC DRAIN LINE CLEAR
  1. Routine Check-ups. ...
  2. Clear Obstructions Near the Outdoor Unit. ...
  3. Use a Wet-Dry Vacuum to Remove Excess Water. ...
  4. Vinegar Solution for Cleaning. ...
  5. Preventative Maintenance. ...
  6. Professional HVAC Service.

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