Comment: Re:The real questions should be different (Score 4, Insightful) 379
The areas in which most farming is done, i.e. out in the sticks, also have the least amount of gray water due to the low population density. The only way this idea would work was if infrastructure was built to not only partially treat the sewage and runoff from the cities, but then transport it possibly hundreds of miles to where it's most needed for agriculture.