All water emanating from an air conditioner is condensation, a byproduct of the cooling mechanism used by the unit. Indoor air is pulled across cold copper coils filled with refrigerant.
These coils "sweat" the humidity in the air into condensation, just as a cold glass of water sweats in a hot room. The condensation is then drained out of the system and dumped outside.
Condensation water is distilled water. This means it lacks the necessary dissolved solids to make it safe for human consumption.
Distilled water is also significantly more corrosive to ferrous metals than non-distilled water. Furthermore, distilled water is quite bitter to the taste, and drinking it will not be a pleasant experience even if no ill health effects are experienced.
Indoor Air Pollution
The water emanating from your air conditioner has been pulled from the indoor air. This means it contains at least trace amounts of all the indoor air impurities homeowners concern themselves with.
Mold and mildew, fungal spores, human skin cells and even chemicals exuded from furniture and construction materials all make their way into this water. This makes drinking the water a very real health hazard.
Internal Conditions in the Air Conditioner
Water is removed from the air in your air conditioner as a byproduct of its method of cooling. No part of the design of your air conditioner is constructed with the intention of having potable water pass over it.
As such, lead solder is used on the copper coils, and no particular attention is given to ensuring there are antibacterial and anti-fungal surfaces on the condensation pan. The entire system is designed to dehumidify the air and quickly do away with the waste water, not to produce safe, drinkable water for human consumption.