In principle, there is not much difference. They both rely on water to drive the rotor to turn to produce electricity. However, hydropower generally refers to the use of height differences in reservoir water levels to produce electricity, which requires larger devices. The tap water pipes are so thin and the installation is small. I'm afraid the difference between the two is not minimal in terms of technical details. As far as I know, hydroelectric technology is mature. If hydroelectric technology is used as a benchmark in producing electricity from tap water, it will at most be considered a practical new technology and not an invention.
And from the point of view of energy saving, the water pressure in the water pipe is obtained by human consumption of energy. Adding devices tothe water line will definitely cause you to lose some of the water pressure, meaning that of the water company. energy is lost. The ideal is to convert the water company's energy into your own electricity without loss, while sacrificing your own water pressure. There is neither an increase nor a saving in energy for society as a whole.