I am just a mechanical engineering student and I do not know how a water supplying system works exactly. In addition to this, some systems have their own special design so I cannot make a detailed explanation. However, bypassing the pressure before the water enters the system may be the solution. I do not know how to do it or even whether it is possible.
Edit: I have an idea to bypass pressure but I cannot guarantee that it is compatible with the current system in your country.
Especially in the old waterworks systems, there are water towers or similar structures where the water is stored at the higher levels than public buildings. As the amount and height of the buildings have increased, these structures have become insufficient to provide convenient pressure. In order to overcome this issue, water pumps are generally used.
As I stated before, I do not know how a water supplying system works and how your system was designed; so, I cannot ensure that my solution will work but I have different solutions for different types of systems. Hopefully one of these is convenient for you.
If the water pumps are placed at the exit of the water towers, the pressure which is provided by the pumps can be decreased just by adjusting them. However, if the pumps are placed at each individual building, there is nothing to do with the pumps.
If there are no water pumps or they are placed at the each individual building, the pressure must be decreased just after the water exits the water tower. The question is how to bypass the pressure in this case. If a container which has an enough size is placed at a level that is below the level of public buildings just after the water exits the tower, the major part of pressure will be bared by this container. If the pressure is not enough after this process, water pumps can be used again to raise pressure to a convenient level.