Addoung a pump can lower the pressure at your end of the pipe to (almost)
0, from 1 bar. but not any more.

Well it can go below zero (assuming we are relative to atmospheric pressure,
not absolute zero). The problem is that negative pressure means that the
company's leaky pipes start leaking in the other direction, so you get the
earthy skank in the fresh water, rather than fresh water in the earthy
skank. This is why you are not allowed to pump a mains supply.

Christian.