We have a rainwater tank, which i thought was huge...but it's surprising how much water washing the car and watering the vegies uses. If anything in the garden needs watering to live...then i'm afraid it doesn't live! I let nature take it's course! I only have plants left that can survive on it's own (oh, except the vegies of course).

Also (this might sounds gross to some!) if i am washing sheets or towels or normal (not too dirty clothes) I save the rinse water (the last lot that comes out) and bucket it back in to the washing machine, and it becomes the wash water for the next load i put in.