What Causes an Air Conditioning Unit to Leak Water?

November 21, 2023

When your air conditioner starts blowing out water instead of cool, refreshing air, it can be both frustrating and concerning. Not only does it compromise the comfort of your living space, but it may also indicate a potential issue with your Air Conditioning unit. In this blog post, we'll explore the common reasons behind air conditioners leaking water and provide practical solutions to help you address the problem.


  1. Clogged or Dirty Air Filter: One of the primary reasons for water leakage in air conditioners is a clogged or dirty air filter. When the filter becomes obstructed with dust, dirt, and debris, it restricts the airflow, causing the evaporator coil to freeze. As the ice melts, excess water may drip into the unit and result in water blowing out through the vents.

Solution: Regularly check and replace your air filter according to the manufacturer's recommendations, typically every 1-3 months. This simple maintenance task not only prevents water leakage but also improves the overall efficiency of your air conditioner.


  1. Frozen Evaporator Coil: A frozen evaporator coil is another common culprit behind water leakage. When the coil freezes, it can't effectively remove moisture from the air. As the ice melts, the excess water may overwhelm the drainage system, leading to water blowing out of the vents.

Solution: If you suspect a frozen evaporator coil, turn off your AC unit and let it thaw completely before restarting. Additionally, ensure proper airflow by keeping vents unobstructed and addressing any issues with the blower motor or fan.


  1. Blocked Condensate Drain Line: The condensate drain line is responsible for carrying excess moisture away from the AC unit. Over time, this line can become clogged with algae, mold, or debris, causing water to back up into the system.

Solution: Regularly inspect and clean the condensate drain line to prevent clogs. A mixture of bleach and water can be poured into the line to inhibit the growth of algae and mold. If the blockage persists, consider seeking professional assistance to clear the line thoroughly.


  1. Incorrectly Sized AC Unit: An air conditioner that is too large for the space it is cooling may cool the air too quickly, leading to inadequate dehumidification. The excess moisture may then accumulate and result in water blowing out through the vents.

Solution: Ensure your AC unit is appropriately sized for your living space. Consult with HVAC professionals to determine the correct size and efficiency rating for optimal performance.


Experiencing water blowing out of your air conditioner is undoubtedly a cause for concern, but understanding the underlying issues can help you address the problem effectively. By regularly maintaining your AC unit, checking and replacing air filters, and addressing any drainage issues promptly, you can ensure your air conditioner operates efficiently and keeps your home cool and comfortable. If problems persist, don't hesitate to contact the team at Simpson Climate Control to assist in this issue.

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