Roux mention in this answer smoking water. How do you do this? What does it taste like? How do you use it?
Fill a basin or hotel pan with water.
Place in your smoker. Ensure the smoker heat is set below 100C/212F (adjust as necessary for distance above/below sea level).
Um... smoke. An hour should do fine. More if you want more. Optionally strain through a superbag or muslin to remove any deposited particulate matter.