This is £828 per year..... a little more than your estimate steve
Definitely!
It will depend on how efficient your filter system is.
i.e. filtered water / waste ratio etc. and how much you filter per day etc.
My calculation was based on the following:-
cost £1.063/ m3
Standing Charge £0.0657 / day
300 litres x 5 days x 48 weeks =
0.3x5x48x£1.063=£76.54 p.a for good water
£44.46 for waste water
I did forget to add the standing charge
£23.98 for standing charge
Revised Total of
£144.98 pa
Steve