EPA Proposes Plan to Contain Groundwater Contamination at Orange County North Basin Superfund Site

U.S. Environmental Protection Agency (EPA) has released a proposed interim cleanup plan to contain contaminated groundwater at the most impacted areas of the Orange County North Basin (OCNB) Superfund site , located in the northern part of the Orange County Groundwater Basin in California. The agency is seeking public input on the plan, which focuses on parts of Anaheim, Fullerton, and Buena Park. 

"EPA encourages people to make their voices heard on our proposed Orange County North Basin cleanup plan," said EPA Pacific Southwest Region Superfund and Emergency Management Director Michael Montgomery. "This proposal is a big step forward to protect groundwater and ensure safe drinking water for Orange County communities." 

Past industrial activities contaminated a 6.4 square-mile portion of the groundwater basin, with contamination detected as far as 500 feet below the surface of the ground. Groundwater makes up 85% of the drinking water supply for central Orange County. Six drinking water wells were taken out of service in Fullerton and Anaheim due to the contamination to help ensure that alldrinking water currently served meets federal and state health and safety standards. The proposed plan will prevent future impacts to other supply wells and may eventually allow for the safe operation of wells that have been taken out of service.

EPA's plan includes installing approximately 17 extraction wells to draw out contaminated groundwater, building a centralized treatment plant, and installing approximately 17 injection wells to return treated water underground. The plan also includes monitoring to track contamination levels and controls to restrict groundwater use in the most contaminated area. 

The public comment period for the proposed plan runs until February 19, 2026. EPA will host a public meeting on January 29 to discuss the Proposed Plan. Information on the meeting, including a pre-recorded presentation, is available online at the Orange County North Basin Superfund site webpage.  

Background

The Orange County North Basin site was added to EPA's National Priority List of Superfund sites in September 2020. The federal Superfund program, established under the law in 1980, investigates and cleans up the most complex, uncontrolled, or abandoned hazardous waste sites in the country and endeavors to return them to productive use. 

For more information about the OCNB Superfund site and to review the Proposed Plan, visit the Orange County North Basin Superfund site webpage. 

Learn more about Superfund and other cleanup sites in the Pacific Southwest. 

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