Under a state law passed last year that is the first of its kind in the nation, patches of grass like this, found along streets and at housing developments and commercial sites in and around Las Vegas, must be removed in favor of more desert-friendly landscaping.

The offense? They are “nonfunctional,” serving only an aesthetic purpose. Seldom, if ever, walked on and kept alive by sprinklers, they are wasting a resource, water, that has become increasingly precious.

Outlawing grass is perhaps the most dramatic effort yet to conserve water in the Southwest, where decades of growth and 20 years of drought made worse by a warming climate have led to dwindling supplies from the Colorado River, which serves Nevada and six other states, Native American tribes and Mexico.