Can Our Air Conditioner Condensate Expose Someone to Legionella and Legionnaire’s Disease?

There is mixed opinion as to whether Legionnaire’s disease can be contracted from an air conditioner’s condensate pan or drain. What are the arguments for and against this threat for Legionella and Legionnaire’s Disease?
3 reasons why air conditioner condensate is not likely to be a threat for Legionella and Legionnaires:
  1. Condensate is water vapor (the gas form of water) that has been cooled from the air to form liquid water. It generally does not come into contact with anything other than the cold coils and condensate pan so there is no source water pathway for the bacteria to get into the condensate.
  2. Condensate is comparable to distilled water in that is produced through a similar but less controlled process. The resulting liquid water has low mineral and chemical content.
  3. The air conditioning condensate is typically run directly to the sewer via a pipe and does not become aerosolized and is therefore not breathed in by humans
Here are 3 low probability reasons why air conditioner condensate could be a threat for Legionella and Legionnaires:
  1. Aerosolized water from a source other than the condenser could contaminate the condensate. For example, bacteria-laden droplets of aerosolized water from another process float through the air and land in the condensate pan.
  2. Once bacteria, including Legionella, is in the condensate collection area, this will of course contaminate the condensate unless it is disinfected.
  3. While air conditioner condensate that is run directly to the sewer or a closed industrial process is not likely to expose humans to an aerosol version of the condensate, reuse or recycle of the condensate such as in a sprinkler system may lead to human contact and the breathing in of water particles that contain Legionella bacteria.
What should you do?
What is your best approach for dealing with air conditioner condensate and its threat for Legionella and Legionnaire’s Disease? Contact the independent experts at Nancrede Engineering. A risk assessment by an experienced Legionella control expert is the only way to be assured that you are mitigating and controlling this possible life-threatening bacteria.
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