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.
Father and son playing at home
Apr 24, 2025
Apr 24, 2025
Heating and cooling system on the fritz? Discover the factors that go into HVAC repair costs and how you can save money on this crucial home update.
Heat pump exterior backyard
Apr 22, 2025
Apr 22, 2025
A heat pump is an eco-friendly heating and cooling system that can save you money on utilities each month. Find out the cost of a heat pump with this guide.
A woman turning on AC unit
Apr 16, 2025
Apr 16, 2025
The cost of a new AC unit depends on the size and type. Our guide breaks down AC replacement cost factors so you can decide which option matches your budget.
A woman covered in a blanket reading a book
Apr 23, 2025
Apr 23, 2025
Whether you’ve lost heat or your furnace is making strange sounds, stay calm. Use this guide to determine the source of the problem and your next steps.
A woman covered in a blanket drinking some coffee
Apr 22, 2025
Apr 22, 2025
Why are some rooms colder than others? If your living room is toasty but the bedroom is freezing, here are a few reasons why and how to fix it.
Woman and cat sitting with a blanket
Apr 22, 2025
Apr 22, 2025
If your furnace is making loud noises, it could be the first sign something is failing. This guide will go over some of your furnace’s most noisy issues.