Pressure is a type of potential energy. To be converted into electrical energy, it must do work, that is, convert potential energy into electrical energy. The so-called conversion means losing potential energy in order to obtain electrical energy. Using your proposition i.e. water should flow downwards. The potential energy from the energy change is then transformed into rotational motion through the turbine, driving the generator to produce electricity. Theoretically speaking, water from the tap water pipe can power a small electricity generation device, which is suitable for experiments, but of little practical value.
Anthracene, this water tank does not need to be changed after a single use. It can be changed after running for a while, for example around February. As long as there is water in the water tank during operationoning and the machine is not fried, everything will be fine. If it is a generator, it can run continuously because it has many generators that can produce electricity in turn. If it is a single machine, it should run for a while and let the machine rest and cool down. To avoid burning the cylinder and piston! !