I've been thinking. I know that's a dangerous thing, generally.
But have you ever wondered why we flush with fresh water in our homes? I mean it certainly isn't a necessity to flush the toilet with the cleanest water available. I know there are systems that can flush with grey water from the grey water sources in the home.... but what about trailers? It's been a while since I've even been in a self contained trailer... seems to me they all used some sort of scented blue chemically treated water. Are there systems that utilize grey water?