Check out this great article written by a NASA scientist! It's a few years old but what it covers is pretty up to date. Did you know that turf is the single largest irrigated "crop" in America, more even than corn?
While she notes the obvious about the impact of lawns on our water supply she does note that it is useful for carbon sequestration which is being used as an argument by the turf industry for why lawns are actually environmentally friendly. Unfortunately they don't mention that ALL plants sequester carbon and the overall surface area of leaves from a 5x5 drought tolerant shrub is probably at least if not more than a 5 sq. foot patch of lawn and it takes less water, less maintenance, and doesn't need fertilizers, pesticides, or herbicides to thrive!!
Check out the article here.