That’s an interesting analogy. But just like too much current can melt a wire, I would assume there’s some upper limits to keep it from bursting pipes and fittings?
US. I’d be surprised if anywhere was allowing more than 80psi.
20psi is really low so this value may have different variations. I’m on a well pump and before I replaced it I was getting down to 20psi. It barely dribbled out of the 2nd floor shower head. I now have the pump set to 60/40 with a 50psi restriction valve. This seems to be the sweet spot.
I’m not in plumbing and won’t know how to look this stuff up.