I'm a plumber by trade and by no means a Horticulturalist, In south Oz most trades get sent out important notices re issues in the work place and a hot topic is grey water, I tend to agree with the authorities, Dishwater has detergent in it, your laundry water has what ever you have come into contact with on them, and blue collar worker are exposed to all sorts of nasties, Laundry waste and detergents and bleaches, this is one of the main reason septic tanks stop braking down organic material. Shower water has Human waste and if stored at the right temperature bacteria will multiply fast in a grey water catchment system, A good water treatment system would have pumps aerator's UV sterilisation which uses electricity, which means your not saving much..
The point i was making is in most cases grey water is harder to install and it seems to be trendy to have a grey water system at the moment, I've been asked to convert houses over to grey water and they don't even have rainwater tanks, WTF?
Then there's the neighbour putting there grey water in the garden, they don't care what goes down the drain because they don't grow veggies, unfortunately Billy Bunter next door is coping his neighbour's run off or ground seepage into his daily bread.......
I know the people on this website are aware of whats the right and wrong thing to put down the sink but you are a minority, I advertised for months green plumbing options and water saving ideas, and never got one call,
I've heard out side of my trade that hepatitis can be spread thru human waste on veggies, and as far as I'm concerned Grey and Black are the same thing, the chances of infections is very minimal i agree, But why go to the trouble, as most times it is much easier to harvest rain water, If you want to use grey water on veggies fine, I personally wouldn't do it,
"Don't worry, It only seams Kinky the first Time"