While it is good to have an electric water pump with a big tank of water, it would also be good for every household to have a deep well pump. That is because when the power interruption lasts all day, chances are, the water that was already stored in your tank will be used up by the end of the day. Unless you have a really big thank, a whole day brownout could be a problem.
This is also a problem when the water system breaks down. But if you have a manual deep well pump, you can just easily pump the water out. Well, it does take some effort, but at least you have water to use for the household needs.