Hot water for larger new builds

Perhaps mains cold water and a mains-pressure unvented hot water cylinder? ie if the mains stops then all water stops, unless you let air into the system and drain the cylinder. Or a thermal store, in which case there's no stored water at all.

In a larger build you could be wanting multiple showers at the same time, which means you want stored water, rather than relying on a combi.

Theo

We've had the plumbing in this house pretty much completely rejigged.

When we bought it there was no upstairs bathroom. I made sure the cold feed to there was straight mains, because we clean our teeth in it.

The shower is in the old downstairs bathroom, and the cold in there is all off the tank. It makes the shower behave better. It also means that in the case the mains fails we still have a flushing toilet.

(The shower has to be downstairs - there isn't enough headroom upstairs for one. Price of a pretty old cottage)

Andy

I have seen that in a reasonably grand 6 bed new build - 2x 250L unvented cylinders. Probably a solar coil as well to push a few greenwash buttons.

The water comes out of the top, so you'd need to syphon it out, or use the drain off to get any water out of it once the inbuilt pressure has gone.