I think sliding the xeriscaping incentive up along with water rates could make people move along more quickly to conserve. The economics will speak for themselves.
I don't think we need to give incentives. Increasing rates dramatically for fresh water usage, along with the "incentive" of not having to relocate should be a good start.
Any increase in your water bill for your showering, laundry, etc will easily be cheaper than the skyrocketing food bills that are imminent should this drought continue........
In Vegas you can only water your lawn on certain days, and they have enforcement that drives around and writes tickets to those who don't comply. I am not for that kind of intrusion, though.