A very off topic off topic!
I'm trying to work out what size water storage tank I will require for our house but I'm not sure if I've calculated it properly.
The surface area of the roof is approx. 90m2. and from what I can work out average rainfall per year 1150mm per year. From what I can work out that should equal about 103500L per year.
Is this correct? It seems like a lot!
Cheers