The water that comes from the AC is the accumulated water on the evaporator coil. It cools as the  AC dehumidifies the air. This water drips from the canal and exits through the pump or water outlet. This water is not toxic. It is dehumidified air. So it is perfectly fine to rinse your mouth with the water coming out of this exit pump.  But given the fact that this pump is exposed out, the cleanliness of the pump is questionable. If it accumulates dust, then the water might not be a good idea for rinsing purpose.