Air Conditioner Leaking Water: Causes and How to stop it

If you’ve ever noticed water leaking from your air conditioner, you’re not alone. Many air conditioners units can suffer from water leaks, and this can be a major cause of concern for homeowners.

In this blog post, we’ll explain why your air conditioner is leaking water, as well as how to stop them from doing so. We’ll also provide tips to prevent water leaks from your air conditioner in the future, so you can keep your home dry and comfortable year-round.

Whether you have a leaking issue with your window or portable air conditioner, keep reading to learn about how you can stop water leaking from your air conditioner.

Table of Contents

Why Is My Air Conditioner Leaking Water?

Air conditioner leaking water

Check out eleven of the most common reasons why an air conditioner leaks water so you can troubleshoot the problem and get your air conditioner running again.

1) A Clogged Condensate Drain

One of the most common causes of an air conditioner leaking water from inside is a clogged condensate drain. This is a pipe that connects to the evaporator coil and collects the condensation that forms during the cooling process.

If the drain is blocked, condensation will build up inside the system and eventually cause water leaks. A buildup of dirt, debris, mold and mildew can cause the condensate drain to become clogged.

2) A Refrigerant Leak

If your air conditioner is leaking water from inside, it could be due to a refrigerant leak. Refrigerant, or coolant, helps cool the air in your home. If there is a crack in the coolant line, it could be causing a refrigerant leak.

This type of leak will cause the air conditioning unit to run inefficiently, resulting in increased amounts of water leaking through the condensate drain. Apart from water leaks, refrigerant leaks will also increase energy bills and you may also hear strange noises coming from the unit.

3) Malfunctioning evaporator coil

A malfunctioning evaporator coil can be another possible reason for water leaking from inside an air conditioner. The evaporator coil, found inside the indoor unit of an air conditioning system, absorbs heat from the air and transfers it to the refrigerant in the coil.

If the evaporator coil is not working properly, it will not be able to absorb and transfer heat properly, and this can cause water to leak out of the air conditioner.

4) Debris or dirt accumulation

When debris and dirt build up in your air conditioning system, it can cause water to leak from your unit. This can be caused by leaves, dirt and other debris being drawn into the unit from outside. When debris accumulates in the condensate pan or evaporator coil, it can create a blockage that allows water to drain out of the unit.

5) Frozen evaporator coil

A frozen evaporator coil is another common cause of an air conditioner water leak. When the evaporator coil gets too cold, it can start to freeze up. When the temperature rises, this ice melts and water starts leaking from the AC unit. 

The reason this happens is that the evaporator coil is not getting enough airflow, which means it is not removing enough heat from the air passing through it. This causes the coil to get too cold and freeze.

6) Clogged air filter

An air filter that is blocked with dirt and debris is another frequent reason for water leakage in an air conditioner. The purpose of air filters is to eliminate dirt, dust, and other airborne particles from the air before it is circulated by the air conditioning system.

When the air filter becomes clogged, airflow can be restricted, resulting in excessive moisture build-up in the evaporator coils. If this build-up of moisture is not addressed quickly, it can lead to water leaking from the air conditioner. This is the most common cause of a window air conditioner leaking water.

7) Incorrectly Sized AC Unit

An AC unit that is too large or too small for the space can cause water leaks. If the unit is too large, it will cool the space too quickly, and will not have time to properly vent the air, which will lead to condensation and water leaks. 

If the unit is too small, it will run continuously, causing moisture to build up and condense on the evaporator coils. It is important to ensure that your AC unit is sized correctly for the space it is intended to cool in order to avoid water leakage from mis-sizing.

8) The air conditioner installation is not proper.

This mostly cause the reason of portable air conditioner leaking water. According to, improper installation of your air conditioner can lead to a variety of problems, one of which is water leakage. If the unit is not installed correctly, condensate drain lines may be blocked or the seals on the unit may not be tight enough. This may cause water to leak from the unit.

9) Cold outside weather

When the temperature drops outside, your air conditioner has to work harder to cool your home. This can cause your air conditioner to produce more condensation which can lead to water leaks. If you live in a cold climate, it’s important to make sure your air conditioner is properly insulated and waterproof.

10) The air conditioner seals are defective.

One of the most common causes of an air conditioner leaking water is a faulty seal. The seals are designed to prevent moisture from entering the air conditioning unit, but if they become damaged, worn or cracked, they can start to leak water from the unit.

11) Aging air conditioner

As an air conditioner gets older, it becomes less efficient and may start to leak water. This is caused by a number of different factors, including wear and tear on the unit, cracks in the air conditioning system, and worn seals.

Over time, the seals that are meant to keep the refrigerant in and the moisture out will begin to weaken and may eventually fail. When this happens, water that builds up as a byproduct of the cooling process can leak out of the unit and cause water damage. 

Additionally, older air conditioners may be missing parts or have worn components that are no longer able to adequately regulate temperature or control humidity levels. These problems can contribute to water leakage from your air conditioner.

How to Prevent Water Leaks from Your Air Conditioner: 15 Ways 

Water leaks in an air conditioner can be frustrating and damaging, but thankfully there are some easy steps you can take to prevent water leaks in your air conditioner. Here we will talk about 15 ways by which you can help stop water leakage from your air conditioner.

1) Schedule regular maintenance for your air conditioner

Maintaining air conditioners

Regular maintenance of your air conditioner is by far the best way to prevent water leaks from your air conditioner and any other issues. You can do this yourself or you can hire an HVAC professional to do it for you. Professional HVAC technicians can inspect your air conditioner and identify any potential problems before they cause water leaks.

During the maintenance check, the technician will check the refrigerant level, inspect the condensate drain line, clean the evaporator coil, lubricate moving parts, check the blower wheel and fan, inspect the outdoor unit, and check the air filter.

By the way, if you prefer to save money and handle air conditioner maintenance tasks on your own, check out our comprehensive guide on the subject. It includes all the information you need to perform regular maintenance on your air conditioner and help prevent water leakage. You can view it by clicking: Cleaning and maintaining guides.

2) Check the condensate drain line

It is important to regularly check your air conditioner’s condensate drain line to make sure it is clear and unobstructed. If the condensate drain line becomes clogged or blocked, this can cause water to back up and leak out of the unit. 

Here are the steps for unclogging a clogged AC condensate drain line:

  1. Disconnect power to your air conditioner to ensure safety when working with the unit. This is important as it is necessary to protect yourself from electric shock or injury.
  2. Locate the drain line. This is usually a small plastic pipe that runs from the air conditioner unit to the outside of your home.
  3. Look for any visible blockages in the drain line. If you see any debris, gently remove it with a small tool such as a wire hanger.
  4. If the blockage is not visible or cannot be easily removed, you may need to use a vacuum to suck out the obstruction.
  5. If the drain line is still clogged after attempting to remove the blockage, you may need to use a chemical drain cleaner to break up the obstruction. And for this, you’ll need to follow the instructions on the product carefully and use caution when handling chemicals.
  6. Once the drain line is clear, turn the power back on to your air conditioner and test it to ensure that the water is flowing properly.
  7. If the drain line continues to clog, you may need to call a HVAC technician to diagnose and fix the problem.

More: How to Unclog Your AC Condensate Drain Line

3) Make sure the area around your air conditioner is clean

The area around your air conditioner should always be kept clean and free of debris, dirt and clutter. Regularly cleaning the exterior of your air conditioner will help prevent dust, pollen, and other airborne particles from entering the unit.

This can reduce the risk of water leaking out of your air conditioner. You should also make sure that any vegetation such as grass and weeds are cleared from around the unit. If these materials are left near the unit, they can block air flow and cause the unit to overheat, which can also lead to water leaks.

4) Check the evaporator coil regularly

The evaporator coil is an important part of your air conditioner that helps cool the air. When your air conditioner is running, the evaporator coil absorbs heat from the air and transfers it to the outside. If the evaporator coil becomes clogged or dirty, it will not be able to effectively absorb heat, which can cause water to leak from your air conditioner. This is the most in a window air conditioner water leaking issue.

It is important to regularly inspect the evaporator coil for signs of dirt, dust, or debris. You can do this by removing the cover of the air conditioner and looking inside. If you see dirt or debris, you should clean it before it does more damage. You can use a vacuum cleaner to get rid of most of the dirt and debris.

5) Seal the ductwork properly

Properly sealing your air conditioner’s ductwork is essential to prevent water leakage. Ducts are passageways for air to travel through and they can become damaged over time if not sealed properly.

To make sure your ducts seal properly, you will need to inspect them periodically and make sure all joints and seams are securely fastened and that there are no gaps or holes where air can escape. . You may need to use a sealant to fill any gaps or cracks in the ductwork. Additionally, inspect the insulation around the ducts to confirm that it is not damaged and is in good condition. 

6) Don’t use the air conditioner when it’s raining

Using your air conditioner during rain can be a recipe for disaster. Rain water can easily enter the unit and cause serious damage to components. Additionally, if you have a condensate drain line, rainwater can back up into the system and cause flooding. To avoid this problem, be sure to turn off your air conditioner before it starts raining and wait until the rain has stopped before turning it back on.

7) Clean and replace the air filter

It is important to clean or change your air filter to prevent water leaks and keep your air conditioner running efficiently.

Dirty air filters can reduce the efficiency of your system and cause more dust and allergens to enter your home.

Cleaning the air filter

Regularly cleaning or replacing the air filter can help prevent water leaks by reducing the amount of dust and other particles that can clog the evaporator coils. Cleaning the air filter every month is recommended by and it should not be ignored, and according to, you should replace the filter every 90 days for basic maintenance, and for optimal efficiency, you can replace it every 45 days.

In addition to preventing water leaks, periodically cleaning or replacing air filters can also improve energy efficiency by allowing better air flow through a more efficient system.

8) Fix any leaks

Water leaking from your air conditioner is a sure sign of trouble. To prevent and repair leaks, you must regularly check all seals and connections in the system. Inspect any tubes, hoses, or connections that may be disconnected, corroded, or cracked. If necessary, use silicone sealant to create a waterproof seal around any problem areas.

9) Insulate the air conditioner

Insulation is an important factor in preventing water leakage from your air conditioner. This is because insulation helps keep cool air inside your home and prevents outside heat from getting inside, which can cause condensation to form. 

You can purchase insulation kits specifically designed for air conditioning systems or use foam board or other types of insulation around the unit. You will need to measure the size of the air conditioner before purchasing the insulation to make sure it fits properly.

Insulation should be applied to all sides of the air conditioner, including the fan, compressor, and all hoses and lines. Make sure all openings are completely sealed with insulation to ensure maximum efficiency.

10) Fix any installation issues

When it comes to stopping water leaks from your air conditioner, one of the most important steps you can take is to make sure any installation issues are addressed. If your air conditioner was not installed properly, it can lead to water leakage from your ac unit which can be harmful to your home. 

Here are some common installation problems that people run into when installing air conditioners, and you should try to avoid them:

  • Not selecting the correct size air conditioner for the space
  • Failing to properly seal the air conditioner
  • Not installing the air conditioner level
  • Not leaving enough clearance around the air conditioner
  • Neglecting to properly insulate the air conditioner
  • Not installing the air conditioner in a location with good airflow
  • Not securing the air conditioner properly

11) Check the refrigerant levels

One of the most important steps you can take to prevent water leaks from your air conditioner is to check the refrigerant level. The amount of refrigerant in your air conditioner helps it run efficiently, so any change in amount can cause a water leak.

Checking refrigerant levels is a job best left to a professional HVAC technician. A qualified technician will be able to check the levels and make any necessary adjustments. They may be able to locate any potential problems that may be causing the refrigerant levels to drop.

By the way, if you’re sure you can do it yourself, check out the link for steps on checking an AC unit’s refrigerant level:

12) Avoid blocking the air conditioner

One way to help prevent water from leaking from your air conditioner is to not block it. Make sure that no furniture or other objects are placed in such a way as to prevent the air conditioner from receiving proper ventilation. These issues are limited to window air conditioners or portable AC units only.

Additionally, move any foliage away from the unit as well, so that there is open space around it. This will ensure that the air can circulate properly and that the air conditioner is not working excessively. If you notice that your air conditioner is clogged, remove whatever is blocking it ASAP.

13) Check the thermostat

Your thermostat is the control panel of your air conditioner and if it is not working properly it can cause water leaks. When checking your thermostat, make sure it is properly calibrated. If the temperature setting is too low, it may cause the system to run too long and the condensate may not drain off fast enough. 

Read to learn: How to Calibrate Your Thermostat

Also, make sure the thermostat is not exposed to direct sunlight or other heat sources, as this can cause the system to run longer than necessary. If you are having problems with your thermostat, contact a professional for assistance.

14)  Hire a professional for maintenance

If you cannot solve the issues yet it’s time to call a HVAC professional technician.

A qualified technician can perform a thorough inspection of your system and make any necessary repairs or adjustments to ensure it is working at its best.

How to prevent air conditioner leaking water?

Regular maintenance appointments can help prevent a build-up of dirt, dust and other debris that can lead to water leaks.

Read to learn: Tips for Hiring a HVAC technician

15) Replace an aging air conditioner

When an air conditioner is old, it may start to leak water due to wear and tear. It is important to replace the old air conditioner as soon as possible to avoid any potential water damage.

When it’s time to replace your air conditioner, start by doing your research. Compare different models, read reviews, see energy efficiency ratings and check the noise level. This will help you decide which air conditioner is best for your home.

Tips to prevent water leakage from air conditioners in future

  • Monitor and maintain your air conditioner regularly. Check for cracks in the evaporator coil, leaks in the ductwork, or other problems. Change air filters regularly and schedule regular maintenance appointments to keep your system running efficiently. Remember, maintaining an air conditioner is the key to increasing its efficiency, performance and longevity.
  • Make sure your device is nicely installed. Correct any installation problems, check for proper insulation and check weatherstripping around doors and windows.
  • Make sure your thermostat is set to the correct temperature and the refrigerant level is correct.
  • Check the condensate drain line regularly and make sure it is not blocked. If so, use a wet/dry vacuum to clear the blockage.
  • Avoid blocking the air conditioner by keeping shrubs and other plants away from it.
  • Consider replacing an old air conditioner if it is more than 10 years old.

An FAQ: How To Stop Air Conditioners From Leaking Water?

This FAQ will answer some of the most common questions people have about how to stop air conditioner water. Keep reading to learn more!

Q1. Is it normal for my AC unit to drip water?

Ans: It depends on the type of air conditioner you have. For most central air conditioning systems, a small amount of condensed water on the outside of the unit is normal. This is due to the evaporator coil cooling down and dehumidifying the air.

However, if your air conditioner is leaking large amounts of water, it could be a sign of a problem with your unit and it’s best to take action to prevent this from happening.

Q2. Should I call a professional to help me fix my AC unit?

Ans: If your air conditioner is leaking water, it is always best to contact a qualified HVAC technician for assistance. While you can attempt to fix the issue yourself, if you’re not sure of the problem or lack the technical skills, you should leave it to the professionals. 

A qualified technician will have the experience and expertise needed to diagnose the problem quickly and fix it safely. They will be able to identify the source of the leak and advise you on the best solution for your specific unit. Depending on the severity of the problem, they may be able to replace or repair a part or component or recommend a more extensive repair.

Q3. Should I turn off my air conditioner if water is leaking?

Ans: Yes, you should turn off your air conditioner. Water leaks can cause a number of problems, including damage to the air conditioner, water damage to surrounding areas, and an increase in your energy bills. You can avoid these problems and prevent further damage by turning the unit off immediately.

Q4. Is leaking water from the air conditioner dangerous?

Ans: Leaking water from an air conditioner can be dangerous if not taken care of. In most cases, water leaking from the AC unit indicates an underlying problem that must be addressed. If water is allowed to accumulate, it can potentially cause electrical hazards and can also result in the growth of harmful bacteria and mold.

Q5. Why is my portable air conditioner leaking water?

Ans: The most common cause of water leakage in portable air conditioners is due to improper installation and blocking the air conditioner. If the AC is not placed on a flat, level surface, it will not be able to drain properly and water may pool around the unit. Also, if the unit is not receiving proper ventilation, it can be the reason.

Q6. Why is my window air conditioner leaking water?

Ans: Causes of water leaking from a window air conditioner include a clogged condensate drain pan, clogged evaporator coils, and a dirty or blocked air filter.

Outcome: Air Conditioner Leaking Water

In short, an air conditioner that is leaking water can be a nuisance and can even cause damage to your home if left unchecked. Fortunately, there are several steps you can take to try and prevent water leaks from your air conditioner.

By regularly maintaining your AC unit, cleaning drains, and repairing any faulty components, you can keep your air conditioner running smoothly and prevent leaks from occurring. Also remember to keep an eye out for signs of a leak and address any problems as they arise to avoid further damage.

By following these tips, you can keep your air conditioner running efficiently and protect your home from water damage.

More from us:

David Jack

David Jack

David Jack is a veteran when it comes to air conditioners, he love helping people find solutions to their problems with AC units. His specialty is helping people find the right Air-Conditioner for their needs, whether that means replacing a broken unit or adding on to an existing system. He is also great at diagnosing problems and fixing them quickly. He learned this from my father Jack Smith who was an air conditioner repairer, he has 2 years of experience in this field.

We will be happy to hear your thoughts

Leave a reply