The Water Knife by Paolo Bacigalupi

From amazon:

Three very different characters—an orphaned Texan teen marooned in Phoenix; the “water knife” Angel from Las Vegas who will break any law he needs to in order to pave the way for his boss to gain the water rights she wants; and journalist Lucy Monroe, who has adopted drought-decimated Phoenix as her own—thrust Bacigalupi’s near-future tale through violence and betrayal toward a blockbuster conclusion that could well be one of the best endings of the year. Murder and torture are everyday events in dusty Phoenix, which is loosely controlled by a sociopathic crime lord, a Chinese construction company that’s offering the only jobs in town, Californian interests, and Las Vegas’ shadowy water knives—former criminals and ex-military who enforce the water rights bought or extorted by their powerful boss. When a rumor surfaces of water rights so senior that they would trump all existing rights and give Phoenix a chance to bloom instead of continue its rampant slide into death by drought, the race is on to find the rights, and no one will survive unharmed. Bleak, troubling, and at the same time deeply hopeful as Bacigalupi’s complex characters define and defend their loyalties, The Water Knife delivers a final scene as unexpected as it is satisfying.