The California Water Wars had their roots in the late-nineteenth century, when the city of Los Angeles expanded rapidly and outgrew its water supply. Frederick Eaton, first City Engineer and then Mayor of Los Angeles, worked with William Mulholland, Superintendent of the Water Department, to build an aqueduct which would bring water from the nearby Owens Valley into the city. The aqueduct was completed in 1913, after a long and sordid campaign in which Eaton was continually accused (often accurately) of lying and misrepresenting the facts, trying to acquire water rights by stealth and deliberately misrepresenting the scale of the problem.
When the aqueduct began to operate, it quickly drained the Owens Valley, turning much of it into a desert. The farmers in the valley were naturally angered at this threat to their livelihood, and their fury increased when, in 1923, the City of Los Angeles managed to acquire additional water rights to divert the flow from Owens Lake. The lake dried up in 1924, whereupon a group of farmers destroyed part of the aqueduct with dynamite, diverting the water flow back into the valley again.
The conflict continued for the next four years, with farmers attacking the aqueduct and city employees repairing and guarding it. In 1927, the collapse of the Inyo County Bank undermined the economy of Owens Valley to such an extent that many of the farmers faced bankruptcy. The City of Los Angeles bought up much of their land, including the water rights. By 1928, the city owned 90% of the water rights in the valley, guaranteeing the water supply to Los Angeles and ending the Water Wars.