Orange County North Basin Superfund Site

The Orange County North Basin Superfund Site focuses on a six-and-a-half-square-mile portion of the groundwater aquifer located under Fullerton, Anaheim and Placentia.

Manufacturing industries operating primarily in the 1950s, 60s and 70s left a legacy of industrial pollutants at their former factories. The pollutants, mostly volatile organic compounds (VOCs) including solvents and degreasers, have migrated through the soils and into the underlying groundwater. These VOCs have impacted nearby water supply wells causing five of them to be taken out of service.

In September 2020, the Orange County North Basin Superfund Site was listed by the United States Environmental Protection Agency (EPA) as a National Priorities List (NPL or Superfund) site. The goal of the Superfund listing is to get contamination contained and cleaned up, and to compel parties responsible for the contamination to implement and pay for the cleanup.

With oversight from the EPA and several State agencies, OCWD is conducting a Remedial Investigation/Feasibility Study (RI/FS) to further characterize areas with elevated contaminant concentrations (the RI) and develop and evaluate alternatives (the FS) for an Interim Remedy that remediates parts of the plume that pose a more imminent threat to local groundwater supplies. Concurrently, EPA is conducting a separate Comprehensive RI to characterize the extent and concentrations of the VOC plume outside the area targeted for the Interim Remedy.

Pictured above: OCWD started operating extraction well EW-1 in September 2017 to contain VOC-contaminated groundwater in the northeastern part of the North Basin VOC plume. Contamination in that area posed an imminent threat to City of Fullerton production wells, which is why OCWD started operating EW-1 before the Interim Remedy RI/FS was completed and EPA selects a remedy.

North Basin Remedial Investigation

• Final North Basin RI Report
• Final North Basin RI Report Appendices (Excluding C, D, E, J, & M)
• Final North Basin RI Report Appendix C
• Final North Basin RI Report Appendix D
• Final North Basin RI Report Appendix E
• Final North Basin RI Report Appendix J
• Final North Basin RI Report Appendix M