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.

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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.

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