What Is Air Conditioner Drain Slime and How Can You Get Rid of It?

Don’t let slime ruin your cool time

Industrial air conditioner. Air conditioning systems on the background of the house
Photo: ValNik Creations / Adobe Stock
Industrial air conditioner. Air conditioning systems on the background of the house
Photo: ValNik Creations / Adobe Stock
Highlights
  • The slimy substance that appears in your AC is commonly called white slime, and it may show up in your drain line, drain pan, or other parts of your unit.

  • 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.

Get quotes from up to 3 pros!
Enter a zip below and get matched to top-rated pros near you.
Geo Icon

White air conditioner slime often shows up in the summer in your condensate drain line and drip pan when there’s condensation in your air conditioner. If you don’t get rid of slime in your air conditioner drain, it can cause a number of problems, including a clogged condensate line, overflowing drain pan, restricted airflow, and mold in your air conditioner.

Getting Rid of AC Slime

Unfortunately, wiping away the slime or emptying the water in your drain pan isn’t enough to keep it from returning. Instead, you’ll need to deep clean your AC or hire a local air conditioning repair company to do it for you. Either way, the process will involve: 

How to Prevent White Slime

Staying on top of your HVAC maintenance is the best way to keep slime from building up in your air conditioner. At a minimum, this involves replacing dirty air filters, cleaning your evaporator and condenser coils, and vacuuming inside your vents.

Angi Tip

Get your HVAC system serviced and inspected at least once per year. For extra peace of mind, call in a pro twice annually: once before the hottest months of the year and again before the coldest time of year.

Kassidy Barber
Content Editor, Angi

You should also have a professional inspect your air conditioner every year. During this AC service appointment, the technician will make sure everything is running efficiently and look for any potential problems.

With that said, if there’s anything wrong with your air conditioner (for example, your AC is freezing up), don’t wait until the annual servicing to address it. Otherwise, what should be a minor issue might escalate into a more expensive problem.

Frequently Asked Questions

If your drain line is clogged, your AC might stop cooling, shut down, or refuse to turn on at all. Otherwise, you might see your AC leaking water, find standing water or water damage near the unit, or notice a musty smell coming out of your air conditioner or vents.

There are several steps you can take to prevent your AC drain from clogging. This includes cleaning the drain line at least every three months, changing the filter every one to three months, and getting your AC serviced annually. Also, if any problems arise with your AC, hire an HVAC technician to deal with them ASAP.

You can unclog an AC drain line for free if you already have these household ingredients: water, vinegar, and rags. Alternatively, if you’d rather not deal with the mess, you can hire a pro to clear your drain line. If you go that route, an HVAC service call costs between $100 and $250.

Need professional help with your project?
Get quotes from top-rated pros.
The homeowners guide to heating and air conditioning services
From average costs to expert advice, get all the answers you need to get your job done.
A mother laughing while preparing lunch with her son
Jan 30, 2025
Jan 30, 2025
New AC compressor costs depend on factors like the compressor’s size and type. Read on to learn more about ac compressor cost factors, in this guide.
HVAC units on the exterior of a house
Jan 31, 2025
Jan 31, 2025
A worn AC fan motor can cause your system to overheat. Budget for AC unit fan motor costs, including parts and labor, with this guide.
Boy and girl jumping on the couch
Jan 29, 2025
Jan 29, 2025
If your air conditioner won’t turn on or makes chattering noises, you might have a bad contactor. Learn more about AC contactor replacement costs in this guide.
An air conditioner compressor installed outside the house
Jan 31, 2025
Jan 31, 2025
An oversized AC unit can cause indoor humidity and uneven temperatures. Learn how to correct an oversized air conditioner without replacing it.
Man removing ceiling air filter
Jan 31, 2025
Jan 31, 2025
If your air conditioner filter is wet, it could be an issue with the drain pan, condensate line, or evaporator coil. Here’s how to find and fix the problem.
window air conditioner in apartment
Jan 31, 2025
Jan 31, 2025
Summer, fall, winter, or spring—when is the best time to buy an air conditioner? Our guide provides insight on ideal times to save, your cooling needs, and various types of units.
Share project details to get started.