Water well in Owensmouth, circa 1915. In 1910, the developers of Owensmouth installed a water pump powered with a gas engine to their main well. Though they claimed this local well pumped enough water for a population of 10,000, this was never tested. In 1915, the most of the towns in the San Fernando Valley voted favorably for annexation to Los Angeles which opened up the water from the Owens River Aqueduct to them. San Fernando Valley History Digital Library.