My parents have municipal water but with an ancient galvanized supply line connecting to the water main in a neighbors property far far away. Their water flow is very low; if someone turns a hose on you can’t do anything in the house. Presumably the pipes are constricted, and although they have easement rights to repair the water line, there are other issues that make that difficult.
The question is: are there products available that they could use to make a buffer storage of, say a few hundred gallons, that could then be pressurized with a jet pump or the like to supply the house? I imagine a tank with an integral pump that would just slowly fill up from the supply line and automatically supply say 40 psi water to the house. Max size I think they would need is 200 gallons, they are not heavy water users.