It's very simple... if the vegetation doesn't grow naturally then it shouldn't be allowed in the area. That's how one would successfully reduce the amount of water consumption.

Community parks and recreation areas would be okay but resisdential zones should be mandated to follow xerascaping guidelines. It's ironinc here in Colorado, we have watering restrictions but the HOAs write warning letters when your lawn turns brown. WTF?! It's either one or the other, water or water restrictions. We can't have both.