Yes, that's called a header tank. It's common throughout the UK too. It means low water pressure, especially upstairs. The actual hot water is still in an insul

Yes, that's called a header tank. It's common throughout the UK too. It means low water pressure, especially upstairs. The actual hot water is still in an insulated tank within the house. The header tank holds cold water. Most new installations are unvented systems with no header tank, but this comes with its own tradeoffs. The hot/cold tap thing is funny. We were just taught not to drink from the bathroom tap at all. It still seems gross to me when people do or like in hotels where you have to.