I want to reduce our metered mains water usage. So I'm considering using rain water collected from the roof via a huge water butt outside for flushing the downstairs toilet. I've heard of others that have done this. I just wondered what issues I need to think about?
Has anyone else here done this or know of any associated plumbing diagrams?
Ideally if the butt runs dry then the supply needs to switch back to mains water (either manually or automatically).
Presumably the rain water would need to be filtered to remove any small debris that could block the ballcock valve?
The rain water must be plumbed in so there is no possibility of it feeding back into the mains supply.
I need to check for any associated building laws (here in France).
Advice or suggestions anyone on this project?