Luxury!

Hot and cold running water... and another cold.

This was in The Tenement House in Glasgow. Why?

The plate above the right tap seems to say "Mains"

(On reflection I think that the one on the right is drinking water and the other isn't. My own house has an indirect system . Cold water to the kitchen comes straight from the mains. the rest goes up to a storage tank in the roof and this feeds the bathroom boiler etc. In this case it feeds the second cold tap. It is not suitable for drinking because it has been hanging around in the storage tank.)