Water leaks in air conditioning systems are common. In fact, according to Popular Mechanics, approximately 90 percent of all A/C related service calls are attributed to water leaks and moisture build-up. Water Damage caused by air conditioning units can be disastrous. While a water leak from a burst pipe can seem more urgent, the slow trickle of improperly draining condensation can cause much more severe damage in the long term.

When summer approaches in the Denver area, the air conditioners become more and more utilized. If drainage systems for the unit are not inspected and unclogged of potential debris, this can lead to condensation building up and ultimately leaking onto a floor or possibly onto other parts of the A/C system, causing damage to the unit and forcing the need for repairs.

This article will discuss some of the common ways leaks can occur in an air conditioner and how to prevent them. Sometime these leaks and the resulting damage can be inevitable. Denver residents dealing with water damage caused by leaking A/C units should call the professionals at Restoration Logistics for cleanup and water damage repair services.

Causes and Mitigation Measures for Air Conditioner Water Damage

  • Failed Condensation Pump: This is perhaps one of the most notable causes of A/C related water damage. Condensation pumps are usually located in the attic or the basement of a home and can cause significant damage to either location. Pumps which are located in the attic, for example, can be especially prone to failure. As temperatures rise, the attic can become an oven and eventually putting undue stress on the pump and causing water to leak and leave water lines in the ceiling.
    • Prevention: Have a professional HVAC specialist inspect and service your condensation pump. Over time, mildew and mold can grow and accumulate within the pump resulting in clogs.
  • Clogged Drain: An A/C unit is designed to pull moisture out of the air as it cools or heats a space, acting a dehumidifier for the home. This moisture collects in the form of condensation and the A/C unit is equipped with a drain line specifically for expelling this water. Occasionally, these lines can become clogged and water can back up into the unit and eventually overflowing onto the floor. Some air handlers are located in the attic or crawl space and this water can damage ceilings.
    • Prevention: Schedule proper HVAC maintenance and have a professional ensure these pipes are unclogged and clear. While most obstructions stem from buildup of residues inside the pipe, the exit point of the pipe can become clogged with outside debris. For example, dirt could build up around the pipe or the external portion of the pipe might be frozen during cold weather.
  • Disconnected Drain Pipe: The most common reason for this is improperly installing the pipe fitting and inevitably loosening over time. If a condensation pipe loosens from the unit itself, it can cause moisture to drain onto the ceiling or floor. The water damage caused by the disconnected line will depend on both the location of the pipe (closet, basement, or attic) and whether it is the primary or secondary drain line that is affected.
    • Prevention: Ensure proper fitting of the pipes. It is recommended that you have a professional handle pipe fittings and installations. This will ensure the pipes are the proper type, that they are routed through the space correctly and that the appropriate adhesives are used to fuse the pipes together. Utilizing the wrong pipe material and glue can cause premature disconnection to occur.

Other Ways to Avoid Water Damage Related to Air Conditioners:

  • Ensure your air handler has a secondary drain pipe, particularly if it is located in the attic.
  • Equip your drain pan with an overflow safety switch that will shut the A/C unit off when water levels rise in the pan to avoid water from flooding over.
  • Changing the air filter regularly will prevent the unit from straining and potentially producing more condensation.


  1. Popular Mechanics; Quick Fixes for A/C Systems that Leak Water; http://www.popularmechanics.com/home/how-to/a7782/quick-fixes-for-leaky-ac-systems-8925561/