Distilled
From Applied Optics Wiki
This can be obtained from iBIOS: go down to the first floor of the building, enter the first door on the right (the door is code protected, but it is open all the time at working hours), go straight forward till to the end of the corridor and enter the door at right. Just at the right side of the door, you can see two large boxes labeled "PURITE NAPTUNE". That's where you can get distilled water.