San Fernando Valley Area 4 covers about 5,860 acres near the Los Angeles Department of Water and Power's Pollock Well Field in Los Angeles. The site sits in a heavily developed urban area of mixed residential, commercial, and industrial uses. It was added to the National Priorities List in June 1986 and remains an active Superfund site. No final cleanup remedy has been selected yet, and construction of a permanent cleanup is not complete.
The main contaminants are trichloroethylene (TCE) and perchloroethylene (PCE), both volatile organic compounds (VOCs). These chemicals seeped into the groundwater from historical manufacturing operations dating back to World War II. The San Fernando Valley groundwater basin supplies about 10% of Los Angeles's drinking water, serving residents in Los Angeles, Burbank, Glendale, and the La Crescenta Water District.
Since 1999, the Los Angeles Department of Water and Power has run a Granular Activated Carbon treatment plant at the Pollock Well Field. This plant treats contaminated groundwater before it enters the public water supply. All water delivered to area residents and businesses meets drinking water standards. EPA has determined that human exposure is under control and that groundwater migration is stabilized with no unacceptable discharge to surface water.
EPA is conducting a remedial investigation to decide whether more cleanup steps are needed. As part of that work, EPA sampled indoor air in the Atwater Village area during winter 2021-2022 to check whether chemical vapors from contaminated groundwater were entering homes, businesses, and schools. Preliminary results showed no unacceptable risk to human health. A second round of sampling took place in winter 2022-2023 to confirm those findings. EPA plans to finish the remedial investigation report in 2023-2024 and conduct a feasibility study in 2024. The site is divided into three operable units covering a sitewide area, a basinwide basin area, and the Pollock area, each at different stages of study.
Community members who want updates or have questions can contact EPA's Community Involvement Coordinator or the Remedial Project Manager. EPA has also published two public fact sheets and 13 plume maps showing the extent and movement of groundwater contamination.
