the california state water project, commonly known as the swp, is a state water management project in the u.s. state of california under the supervision of the california department of water resources. the swp is one of the largest public water and power utilities in the world, providing drinking water for more than 23 million people and generating an average of 6,500 gwh of hydroelectricity annually. however, as it is the largest single consumer of power in the state itself, it has a net usage of 5,100 gwh.