Great post and nice replies. That is one of the reasons my wife, three kids and i want to make the move to Northern Queensland. Precisely Cairns. They get about 8 metres of rain a year, thats 24 feet approx.
A couple of rain water tanks and you are set.
Every body in the southern States, NSW, Vic, etc are being encouraged to install rainwater tanks for this reason. This is a typical example.
Good luck guys. I think you should all pack up and move to Australia. We need all the like minded people here.
Henry