Thank you so much for recognising that even though my questions are wrapped in humour, they are conundrums for me. So, I very much appreciate your thoughtful and informed response. I liked the link to the Monte Testaccio. I feel ok with question one now.

I'm still not sure about question 2 because water may end up in the sea, but it still evaporates from there and comes down as rain minus salt and gunk. So, I'm sticking for now with my theory that there is a closed water cycle, and the water companies only want me to use less because it costs them money to filter it (not because there is a shortage). And there definitely isn't a shortage in Haywards Heath because it has done nothing bar rain since I moved here. I do understand that there are issues with WHERE the water falls and problems related to fair distribution. But that isn't something I feel I can help with. And I don't believe that me using less helps someone in the Sahara.

Happy Thursday to you, too, Matthew!