Remember, grass uses far more water than most other plants. Planting ornamental grasses where you could use drought-friendly plants instead is simply a waste of water. The ban on ornamental grass could conserve up to 14 gallons of water per person per day in the Vegas area.  The Southern Nevada Water Authority has put such water-saving measures into place in response to Nevada's two-decade-long drought that shows no signs of improving and the dangerously low levels of Lake Mead, which is currently facing its first federally declared water shortage.