I too live in a very dry area, but here we're actively encouraged to install water tanks and harvest our own water, with the understanding that for each litre o

I too live in a very dry area, but here we're actively encouraged to install water tanks and harvest our own water, with the understanding that for each litre of rain collected about 10 litres of dam water is saved. [Edit: this makes no sense. sorry. What I mean is that if 10% of water makes it to the dams, then for each litre I collect, only about 100mL would have make it into the water supply.]