Water Dripping From Split AC Indoor Unit – 8 Common Causes & Solutions

Split air conditioners are more durable, quiet, and cost less than central air conditioning. This type of air conditioner, however, appears to be more prone to water dripping.

You are not alone if you notice your split AC indoor unit dripping water. A lot of split AC owners have been through this and have found ways to fix it. 

Usually, this is caused by a clogged drain hose, a damaged drip pan, or a dirty air filter. Improper installation, disconnected drain hose, or broken condensate pump can also be to blame.

Continue reading to learn about all of the reasons and solutions! Hopefully, you’ll be able to get your split AC indoor unit to stop dripping soon.

Let’s dive right in!

Can you continue to run your split AC when the indoor unit is dripping water?

On hot summer days, you can’t survive without cool air. That’s why some people will keep running their split air conditioners even if their indoor units are leaking water.

While it may not cause any immediate problems, I recommend that you turn it off and have it repaired as soon as possible.

If you continue to use it, the leaking water may cause internal electrical components to fail, damage your furniture, walls, and floor, and even promote mold and mildew growth. Isn’t it better to be safe than sorry?

Don’t be too concerned! By reading the information in the following section, you should be able to identify and solve the problem in a matter of hours.

Why is water dripping from my split AC indoor unit? [Solutions included]

Again, fixing a split AC indoor unit that is dripping water is not rocket science. I will start with the common, simple issues and move on to more complex problems. You will know exactly how to handle it.

1. Clogged drain pipe

This is the most common cause of a split AC dripping water. Impurities in the air will enter the machine and clog the hose. It will eventually turn into slime and algae, which will affect the flow rate of the water.

If the water cannot drain smoothly, it will back up into the drain pan, causing it to overflow and leak from the indoor unit.

This is especially common in older split air conditioners.

How to fix it?

After removing the air filter, you will see where the drain hose locate. To unclog it, you should disconnect it from the drain hole and then use a wire brush or vacuum cleaner to dislodge the buildup.

To ward off the future growth of gunk and slime, pour some bleach or vinegar through it and clean the hose once a year.

2. Disconnected drain hose

If you notice water dripping from the back of your split AC indoor unit, the drain hose is most likely disconnected from the hole. The accumulated water will constantly leak from the hole and drip on the wall.

How to fix it?

This is also a simple problem to resolve. Simply reconnect it to the drip pan to see if the problem has been resolved. If it happens on a regular basis, the hose end may be loose, and buying a new hose is your best bet because it is inexpensive.

3. Damaged drip pan

Because most AC drip pans are made of iron, they rust easily. If the rust is not addressed early on, cracks or holes will appear in the pan, resulting in leakage in the indoor unit.

How to fix it?

My advice is to replace it with a new pan. However, if you are not in a position to replace it, you can use a soft cloth to remove all the water and apply some acrylic, epoxy, or polyurethane sealants to plug the holes or cracks.

More information on how to repair a rusted AC drip pan can be found here.

4. Dirty air filter

dirty filter in split ac

Some manufacturers claim that their air conditioning units can improve air quality, and it is true. Because the air filter can remove some contaminants that linger in the air, it can help with the air quality in your room. 

However, the filter will get clogged over time and cause the evaporator coil to freeze because the airflow will be reduced, and there is no adequate air to warm up the coil.

When the ice on the evaporator begins to thaw, it will cause water to drip from the indoor unit. 

How to fix it?

Fortunately, cleaning a dirty filter is like a walk in the park. All you need to do is remove it, wash it under running water with a soft brush, and then replace it.

To prevent this from happening again, you should clean the filter on a regular basis. If you have pets at home, you will need to increase the frequency of cleaning.

5. Too much condensate

In rare cases, the dripping water in your split AC is simply caused by the excess moisture in the air other than anything else.

When the indoor humidity is extremely high, it will produce much more condensate than usual, causing the drip pan to overflow

How to fix it?

Since indoor humidity is usually affected by outdoor humidity, this problem will go away when the extreme weather is over.

If you get a lot of extremely humid days, you can try to run your AC with a dehumidifier together. Dehumidifiers are better at removing moisture.

6. Defective condensate pump

If gravity draining is not an option, your split AC must use a condensate pump to pump the water outside the indoor unit.

When the pump fails, the water remains in the pan and leaks through the indoor unit.

How to fix it?

Because the condensate pump is an electrical component, it is best to have a certified HVAC professional repair or replace it because it may involve complicated wiring issues.

7. Refrigerant leak

As mentioned previously, the frozen evaporator coil is the source of water dripping. Except for dirty filters, the low refrigerant level will also make the coil freeze. 

This is because the lack of refrigerant will lead to the low temperature of the evaporator coil, allowing the moisture to turn to ice quickly. 

Since refrigerant circulates in the coils and compressors and stays untouched under normal circumstances, the low level indicates that there is a leak.

How to fix it?

If you are in the US, as far as I know, you are not allowed to recharge an AC. You need to make a call to an HVAC technician, and they will take care of it for you.

8. Improper installation

Having a new split AC is great, but poor installation can ruin your good mood. If the indoor unit is not correctly installed, for example, the technician forgets to put on a drainage hose, the water will drip from the indoor unit.

How to fix it?

Contact an experienced technician to check your unit again. They can inspect the issue and solve it.

In conclusion 

Even though water dripping from the indoor unit is a common issue in split air conditioners, it doesn’t mean that you can leave it unattended. Otherwise, you may end up paying expensive repair bills. 

In most cases, you can get it solved on your own by cleaning the air filter and unclogging the drain hose. Occasionally, the dripping water is a sign that some parts inside are broken, including a drip pan, a condensate pump, or coils. 

A humid climate can also be the culprit. 

With any luck, this guide has helped you to fix a leaking split AC indoor unit.

Have a nice day!

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Liz Yang is the founder of Airsmartly. She has been working at home for a few years and realizes that the performance of the HVAC system plays such an important role in our life. She has tested a lot of products in person, like humidifiers, air purifiers, dehumidifiers, and ACs, and wants to share tips about using or troubleshooting these products with you. Her uncle is an HVAC expert with over 30 years of experience in the field, and often offers assistance when she is unsure how to handle a situation. He is also in charge of reviewing the articles on this site.