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As we all know, the primary purpose of an air conditioner is to keep our homes and offices cool and comfortable during the hot summer months. While it’s normal for an air conditioner to produce some condensation, it’s not normal for it to leak water. If you notice water pooling around your air conditioning unit, it’s essential to identify the problem and address it as soon as possible to avoid potential damage to your property or the unit itself. 

In this article, we will explore the top seven common reasons why your air conditioner might be leaking water and provide some tips on how to fix the problem.

1. Clogged Drain Line

One of the most prominent reasons for a leaking air conditioner is a clogged drain line. This is responsible for removing the condensation that forms as your air conditioning system cools the air. Over time, dirt, dust, and algae can build up inside the drain line, causing it to become clogged and preventing the water from draining properly. This can result in water backing up and leaking from the unit.

Solution: Regular HVAC maintenance service can help prevent clogs in the drain line. However, if you’re already experiencing a leak, you may need to call a professional to clean the drain line and remove any obstructions.

2. Dirty Air Filter

A dirty air filter can also cause your air conditioner to leak water. When the air filter is clogged with dirt and debris, it restricts the airflow over the evaporator coils, causing them to become too cold and freeze. When the ice on the coils melts, it can cause an overflow of water that may leak from the unit.

Solution: To prevent this issue, make sure to clean or replace your air filter regularly, at least once every 1-3 months, depending on usage and environmental factors. Regular HVAC maintenance service can also help keep your air filters clean and functioning correctly.

3. Damaged or Disconnected Drain Pan

The drain pan is located underneath the air conditioning unit and is designed to catch any condensation that drips from the evaporator coils. If the drain pan is damaged, rusted, or disconnected, it may not be able to hold the water, causing it to leak onto the floor.

Solution: Inspect the drain pan for signs of damage or disconnection. If you find any issues, call a professional HVAC technician to repair or replace the drain pan as needed.

4. Low Refrigerant Levels

Low refrigerant levels can make your air conditioner to work harder to cool the air, which can lead to the evaporator coils freezing and eventually melting. When the ice melts, the excess water may leak from the unit.

Solution: If you suspect that your air conditioner is low on refrigerant, it’s essential to call a professional HVAC technician to inspect the system and recharge the refrigerant as needed. It’s also crucial to address any potential refrigerant leaks to ensure proper system performance and prevent future issues.

5. Incorrectly Sized or Installed AC Unit

An air conditioner that is too large for your space or improperly installed can cause problems with condensation and water leaks. An oversized unit may cycle on and off too frequently, causing excess condensation that the drain pan cannot handle. Similarly, an improperly installed unit may not adequately drain the condensation, leading to leaks.

Solution: Consult with a professional HVAC technician to determine if your air conditioning unit is the correct size for your space and ensure it is installed correctly.

6. Damaged or Insufficient Insulation

If the insulation around your air conditioner’s evaporator coils is damaged or insufficient, it can cause the coils to freeze and subsequently leak water when they thaw. Insulation is crucial for maintaining the proper temperature around the coils and preventing freezing.

Solution: Inspect the insulation around your evaporator coils and replace it if necessary. A professional HVAC maintenance service can help ensure your insulation is in good condition.

7. High Humidity Levels

High humidity levels can also cause your air conditioner to leak water. When the air is too humid, it can cause excess condensation on the evaporator coils, overwhelming the drain pan and leading to leaks.

Solution: Consider using a dehumidifier to reduce the humidity levels in your home or office. Additionally, make sure your air conditioning unit is properly sized for your space to prevent excess condensation.


Leaking air conditioners can be a frustrating and potentially costly issue if left unaddressed. By understanding the common reasons why an air conditioner may leak water and taking preventative measures, such as regular HVAC maintenance, you can avoid these issues and keep your home or office cool and comfortable all summer long. If you are experiencing a leaking air conditioner, be sure to contact a professional HVAC technician for proper diagnosis and repair.

Are you looking for reliable HVAC maintenance services in Oshawa? Then look no further than Fortis Heating & Air Conditioning! Our team of experienced technicians is dedicated to keeping your heating and cooling systems running smoothly all year round. From routine maintenance to emergency repairs, we’ve got you covered. Contact us today to schedule your HVAC maintenance appointment and ensure your system is operating at peak performance!

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