Project Overview

The City of Los Angeles is committed to a sustainable water future that relies more on local water supplies than costly and unreliable imported water. The plan to increase local water resources includes groundwater replenishment using recycled water. The Los Angeles Department of Water and Power (LADWP), in partnership with the Los Angeles Bureau of Sanitation (LASAN), is undertaking the Los Angeles Groundwater Replenishment (GWR) Project. The GWR Project will provide up to 30,000 acre-feet per year (AFY) – more than 9.7 billion gallons – of recycled water to replenish the San Fernando Groundwater Basin. The GWR Project is an important investment toward developing a local, safe, and reliable water supply for a sustainable Los Angeles.

The GWR Project will be implemented in phases. The Initial Phase of the GWR Project, which includes the Ozone Demonstration Project, will begin to replenish LA’s groundwater in 2021.

The Ozone Demonstration Project involves adding ozone to the existing, multi-step cleaning process at DCTWRP. Up to 3,500 acre-feet per year, or 3.1 million gallons per day, of this treated water will be delivered through an existing pipeline to the Hansen Spreading Grounds where it will soak into the ground through soils, providing additional highly effective natural treatment through filtration and microbiological activity. The water will remain underground in the San Fernando Groundwater Basin for several years and will add to LA’s future drinking water supply.

Groundwater Replenishment Process

Groundwater Replenishment Process Illustration

Multiple Levels of Treatment

At the Donald C. Tillman Water Reclamation Plant (DCTWRP), operated by LASAN, wastewater from homes and businesses undergoes multiple levels of treatment to produce recycled water. Recycled water is currently used for irrigation, commercial, industrial, and environmental uses. The Ozone Demonstration Project will add ozone treatment as part of the multistep process to enhance recycled water for groundwater replenishment.

Groundwater Replenishment- Multiple Levels of Treatment Illustration

The enhanced recycled water will then be conveyed through an existing recycled water pipeline to the Hansen Spreading Grounds. The water will be added to the spreading grounds where it will flow through the soil to replenish the aquifer in the San Fernando Groundwater Basin.

The water will travel underground for several years until it is pumped out by existing groundwater wells to supplement the City’s drinking water supplies.

Project Update as of February 2019

The GWR Project completed its environmental analysis with the certification of an Environmental Impact Report (EIR) in 2016, following the guidelines for the California Environmental Quality Act (CEQA). Implementation of the Initial Phase and Ozone Demonstration Project is underway with spreading scheduled to begin in 2021.

Follow this link to the GWR Project’s environmental documents.

For questions about this project, email [email protected].