How does that work, considering that you only have a single water line into the house? Shirley all the internal potable water plumbing is at the same pressure?
This is a very modern (last couple of decades) thinking, where everything is fed directly off the mains riser. Which is why in modern houses damage from water leaks is much more common than in older houses...
In traditional (post-WWII) houses only the kitchen cold tape (potable water supply) and attic tank were directly fed from the (high pressure) mains riser, all other water came via the attic tank and hence were at low (ie. gravity) pressure.
The irritation is that a post-WWII plumbed home can be quite readily converted to use rain water collection (ignoring the issues about locating the tank), whereas a modern house can't.
These along with solar-thermal mean you have to have a different attitude to "hot water" as to you it is cheap and plentiful whereas for most 'traditional' homes you have to run the boiler and burn purchased energy...