Colin.
Thanks very much for info.
As said my usage is about 1000 litres a week, tops 1250 litres.
I'm guessing my work water bill would be £500 a year.
My parents currently pay £450 a year, they are not on a water metre, when the are I'm guessing there bill would be less; say £350 a year as 2 people living in house.
So combined bill £1000 a year tops; £20 a week.
Colin regarding sub metre where do I get one?
Can i fit sub metre anywhere along the the outside supply?
My setup is water tap under parents kitchen window, outside in garden.
Then hose to garage 15 feet away through hole in wall. Then into ro system.
Can I fit sub metre in garage? Or will it have to be on tap outside kitchen window?
Sorry for all Questions Colin
Thanks everyone for your help.
Forgot to say have had ro system for quite awhile.
Is it best to imply water setup is new?
Can water board backdate me