离开时断水断电的英语翻译是 "turn off the water and electricity when leaving". 这个短语的来源是由于在大多数情况下，人们会在离开家或办公室时关掉水和电的电闸，以防止意外发生，例如水管破裂或电线断裂。
Here are some examples of how you might use this phrase in Engpsh:
Before you leave the office tonight, don't forget to turn off the water and electricity.
I always turn off the water and electricity when I go on vacation, just to be safe.
Make sure you turn off the water and electricity when you leave the house, or you might come home to a big mess.