More questions from newbie

We are away at a cl in richmond for our first trip and it's lovely.  Firstly we wondered when you leave the caravan for the day do you turn  the electric hot water off. Secondly and more important, when we came there was a steep hill into Richmond 1:7 or 15% with speed bumps.being new to towing I'm worried we can't pull the caravan up it.is this stupid or are their some hills we cannot pull the caravan up. Although we don't have a large tow car, our caravan is very light at about 900kg and it was about 73% of tow weight when we did the match and it has pulled the caravan well on the way here. Am I worrying unnecessarily.