The Decanter of Endless Water text states that:
You can use an action to remove the stopper and speak one of three command words, whereupon an amount of fresh water or salt water (your choice) pours out of the flask. The water stops pouring out at the start of your next turn.
Does this mean that an action must be used to each turn to re-engage the item, or can the command words simply be spoken to activate it again?