I'm actually unaware about how an Air Conditioner (A/C) works. In our office, our A/C's residue (?) pipe is coming out to the toilet floor, and when the A/C is used there tiny droplets come out continuously. Sometimes I jut put a container under the pipe, and could collect a serious amount of water, and the water is damn cold. But for any health risk, we can't use the water.

So, my question is:
Is the water coming out from an A/C clean and hygienic?

  • 1
    Clean and hygienic for what use? We're only guessing, and I'm afraid the answer you solicited is really dangerous for some applications while perfectly safe for others (especially if you don't carefully parse the ifs, ands, or buts). Sure, water your plants... but drinking it might kill you. I hope the users finding this online understand that nuance. Oct 28, 2013 at 17:01
  • @RobertCartaino thanks for the clarification. Opps! Never for drinking at all. :) Oct 28, 2013 at 17:30

1 Answer 1


If you kept the coils clean, filtered the air blowing over them, and captured the water immediately before it had a chance to pool and potentially grow bacteria, then yes, the water is very clean and pure. Probably as pure as distilled water (if not for all of the dust and other contaminants that blow through it).

Legionnaires Disease is an example of a disease that can be spread through aerosolizd water from air conditioning systems:

Legionnaires' Disease and Pontiac Fever (Legionellosis):
"The bacterium thrives in the mist that is sprayed from air-conditioning ducts."

Probably the best thing to do with water collected from an air conditioning system is use it to water plants.

  • Good answer, just to stress the big IF: from my experience the coils are almost never clean, the air filters are dusted and it takes very long to capture the water. That's why the A/C waste water isn't clean nor hygienic.
    – Peter Ivan
    Oct 28, 2013 at 9:25
  • Wouldn't it also depend upon the AC's coils? If the coils contained lead or some other hazardous material (maybe as a coating?) then it would not be safe to drink.
    – BryanH
    Dec 18, 2013 at 16:40

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