How Much Water Should Drain From Air Conditioner: AC Guide

It’s normal for AC units to collect moisture like condensation, leaks, drips, and other forms. In fact, it’s crucial for the efficient and proper operation of air conditioners. However, there is a such thing as too much water draining from the unit.

If you want to find out just how much is the perfect amount, then you’re in the right place because our guide will take you through everything you need to know!

Why Do AC Units Drain Water? Process of Condensation Explained

Why do AC units even produce moisture? Well, remember that they not only cool the air in our homes but condition it as well. This usually happens in hot/humid environments. Condensation is just water vapor that converts into liquid once warm/humid air encounters cold surfaces.

When your unit’s evaporator coil takes humidity from the air, it also shows up as condensation inside the air conditioner. The moisture on the coil drips into a drain pan and down a condensate drain line which is almost always a white PVC pipe, which then goes out of your home. There’s not just a cookie-cutter amount of condensation that’s “too much,” as it varies heavily depending on the humidity of where you’re located.

However, condensation and other moisture produced by the unit can cause damage if you don’t address the cause and relevant solution. If your drain line is clogged, water will build up inside, which can create leaks. If you see a leak, make sure to unplug the AC unit and start looking into the drain line and clear it if it’s plugged up.

through the wall air conditioner

Why is My Air Conditioner Leaking Inside the House?

There are various potential causes for this. Let’s take a look at each of them to help determine how you can address and fix your AC unit’s leaks.

1. Clogged Condensate Drain Line

This one we already went over and is usually caused by dust, dirt, or even mold. The easiest way to fix it is by using a vacuum to suck out the clog!

Related Article How To Clean AC Drain Line

2. Damaged/Rusted Drain Pan

If your AC unit is at least 10 years old, it’s very possible that the drain pan is damaged or rusted so much that the water just goes through it. In this case, your drain pan will need replacing.

3. Broken/Faulty Condensate Pump

If your AC unit is hooked up in your basement, you’ll probably have a condensate pump that moves water outdoors. If this breaks, then the water isn’t being moved outside, and you’ll have to either fix or replace it.

4. Dirty Air Filters

This is one of the most common reasons and easiest to fix. When filters are dirty, the air isn’t able to get through and flow over the evaporator coil, leaving the coil to freeze. Once it starts melting, the resulting water may cause the pan to overflow. These should be changed at least every 3 months.

Related Article How To Clean AC Filter

5. Low Refrigerant

Low refrigerant causes AC units’ pressure to be reduced, and when this happens, the evaporator coil can also freeze. Once it melts, the water will be too much for the drain pan.

How Much Water Should Drain from the Air Conditioner

How much water should drain from window mounted and commonly purchased portable air conditioners? This will vary slightly depending on the season, but you can expect the AC to drain anywhere from around 5 to 20 gallons of water per day.

Just remember that when we are talking about this quantity of water, we’re talking about water outside your home through the condensate drain. You should never be experiencing any water inside your home.

How often should it be drained? Well, the only time you’ll really only need to drain your AC is if the water is collected when using it as a dehumidifier. If this is the case, you should try to clean and drain every 30 days at the very minimum.

rheem air conditioner

Ways to Drain Water from Your Portable AC

Let’s discuss all the different ways to drain water from your AC unit, depending on the brand.

1. How to drain water out of a portable LG air conditioner
  • First, make sure to disconnect and turn off the unit.
  • Find the drain cap in the back, right-hand corner of the unit.
  • Put a container under the cap to catch any liquid/debris, then open it.
  • Let the water drain out. Once no more water is coming out, you can then close the cap and turn the power back on.

View our guide to LG air conditioners here.

2. How to drain water from Honeywell portable air conditioner
  • Unplug the unit from any power.
  • Place a container under the lower drain plug, which is on the bottom center of the unit.
  • Remove the lower drain plug, letting any water drain out. Once the water stops flowing, you can replace the lower drain plug and turn on the unit.
3. How to drain water from Haier portable air conditioner
  • Unplug the unit from all power sources.
  • Place a shallow pan under the lower drain on the rear of the unit, tipping it a bit if needed to get all water out.
  • Once you’ve emptied it of all water, reinsert the drain plug and plug the AC unit back into the power source.

Check out our complete guide to Haier air conditioners here.

4. How to drain water from Soleus air conditioner
  • Remove the pre-installed drain cap
  • Attach clamp with provided screw
  • Attach the drain hose to the drain port with the drain hose clip. Insert drain plug into the open end of the hose, guiding it through the clamp.
  • Once this is done, you can simply remove the drain plug and guide the hose into a small pan.

Check out our guide to Soleus ACs here.

People Also Ask (FAQ)

Should my exterior ACs drain pipe be dripping water?

Yes, there’s nothing to worry about here. The line should drain outside, especially during particularly hot or humid weather.

Why would an overflow pipe drip?

This is usually caused by a clogged condensate drain pipe.

Why is my split AC not dripping water outside?

This is probably because of a clogged condensate drain as well! Learn more about mini-split ductless models here.

Why does my expansion tank keep filling up?

This is usually due to there not being enough air in the expansion tank, which will result in pressure pushing water out of the safety relief valve and the tank filling with water.

Can I put an air conditioner in a room with no windows?

Yes, unless they’re a window unit designed specifically to work mounted in a window.

Why does it sound like there’s water in my window air conditioner?

There’s nothing to worry about here. While it may sound concerning, it’s perfectly normal and to be expected as the unit draws in warm, moist air.


Now that you’ve read all about the most common reasons and fixes for water drainage issues, do you feel more confident about how yours is operating? We hope our guide has been able to help you out so your AC unit works seamlessly for you all summer long.

Josh Mitchell

Josh Mitchell

My name is Josh and I am obsessed with DIY and improving my family home. HVAC topics can be tricky for homeowners so I decided to share my knowledge on the subject. When I am not working on DIY projects, you can find me at the beach or my local coffee shop.