This is one of eight sets of questions to consider when envisioning a city that can win the climate fight. Read the introduction, and take a look at an overview of all eight.
Where does your water come from? How much of it fell from the skies as rain and snow, and how much of it came from aquifers? How fast are those aquifers being depleted? How much rainwater could you harvest from your roof with rain barrels and cisterns? How much water does the average person in your city use, and how does that compare to extremely water-frugal cities, like London or Melbourne, Australia?