Before installing a water supply system in your house, you must carefully calculate everything in order to know how much and what pipes you need to purchase, how many connections are needed, etc. materials. But do not try to take the material back, because there may be such situations when, due to a shortage of several centimeters, you will have to either buy a new pipe, or install the taps in the wrong place where you wanted.
But if you decide to change the water supply in your apartment, then you need to solve some specific issues. One of them is a disconnection of water, which often has to be done throughout the house, and not only in one apartment. Municipal services will help you to do this, but the time for this must be chosen when people are mainly at work and will not suffer much from your work. And be sure to warn the residents about the upcoming shutdown so that they can stock up on water.
Inform your neighbors from above and below that you are changing the pipeline and you will need to crash into their risers. Do not forget that in the apartments of old houses the pipes can be very weak and you risk flooding yourself and your neighbors from below. Therefore, the work must be done carefully and do everything thoroughly, checking everything well before connecting the water again.