I found two potable water fountains at Terminal 1 International Departures.
They are located at the entrance to the toilets in the Duty Free Area. They are quite central-located actually.
Keep in mind that if you try to get a big amount of water, the fountain will temporarily run out of water. I have experienced this when I tried to fill 2.5 liters of water. The machine ran out of water at the level of 2 liters. Anyway it tasted nice.
Have a nice trip! 🙂
#plasticfree #BeatPlasticPollution @BakuAirport