"When John Hiatt moved to southwest Las Vegas in 1976, the water level for his domestic well was 115 feet below the surface. A decade and a half later, it dropped to 140 feet.
Until 1971, groundwater below the earth’s surface was the only source of water in the Las Vegas Valley, Southern Nevada Water Authority spokesperson Bronson Mack said. By the 1970s, population growth and rampant overpumping of the Las Vegas aquifer forced changes to water management, including a transition away from widespread groundwater use to the current reliance on water from the Colorado River.
Net groundwater pumping peaked in 1968 at 86,000 acre-feet and started to go down in the 1980s, '90s and 2000s, according to the state’s 2018 groundwater pumpage inventory for the aquifer. Thanks to the water authority’s efforts to reduce pumping, only 10% of the water used in the valley now comes from groundwater, while the rest comes from Lake Mead, Mack said."