L.A. Mayor Eric Garcetti broke ground Wednesday at the North Hollywood West Groundwater Treatment Project, a plant to restore the use of groundwater for drinking in the San Fernando Valley.

The $92 million project is expected to be completed by early 2020. If clean, the San Fernando Valley Groundwater Basin could provide drinking water to more than 800,000 people. Currently, parts of the Basin are contaminated by industrial pollution dating back to the 1940s, according to the Los Angeles Department of Water & Power.

“Water is our most precious resource – and creating a more resilient, self-reliant Los Angeles means increasing the amount of water we source locally,” Garcetti said in a statement. “The decontamination of this historic groundwater basin is a critical step in achieving our goals to reduce our dependence on imported water.”

The North Hollywood West site is the first of four planned remediation projects in the San Fernando Valley.