The U.S. Environmental Protection Agency (EPA) has assumed lead responsibility for the cleanup of contamination impacting the northern region of the Orange County Groundwater Basin. The Orange County Water District (OCWD) supports this effort and will provide assistance to the EPA as needed.

The EPA's action is expected to significantly enhance efforts to remove toxic chemicals from this important source of water to Orange County. Ensuring we can utilize all of the water from a fully functional groundwater basin not only protects public health, but also ensures the long-term economic viability of all of Orange County.

EPA is stepping in to prevent further degradation of the groundwater basin. Unlike many other sites it oversees, the overall health of the Orange County Groundwater Basin is excellent. The basin is 270 square miles. The North Basin contamination plume has spread out to cover an area of approximately 10 square miles. We have a unique opportunity to capture this plume before it becomes a larger water quality problem.

In a recent letter to state and regional environmental offices announcing its decision, the EPA stated it "understands the vital importance of groundwater resources for meeting the drinking water needs of Orange County, where the groundwater basin supplies water to 19 cities and approximately 2.4 million residents. As groundwater becomes even more invaluable during this period of severe drought, EPA recognizes the necessity of preserving clean drinking water resources to continue to meet the current and future drinking water needs of Southern California."

Because it recognizes the significance of the contamination issue and the impact of pollution on an important water supply, the EPA will use its legal authority to determine the extent of the contamination, explore options for and select a remediation plan, and pursue opportunities for cost recovery from parties responsible for the contamination.

The problem
In the northern section of OCWD's groundwater basin (under Fullerton, Anaheim and Placentia), portions of the Shallow and Principal aquifers are impacted with volatile organic compounds, or VOCs. From the late 1950s through the early 1980s, VOCs were used for industrial degreasing in metals and electronics manufacturing.

Although the Shallow Aquifer is not heavily used for drinking water supplies, groundwater in this aquifer eventually flows into the deeper Principal Aquifer, which is heavily used for this purpose.

To date, three municipal production wells and one private well in the North Basin area have been removed from service due to VOC contamination. It is urgent, therefore, to remove the higher levels of contamination before it has a chance to further contaminate the Principal Aquifer.

OCWD and local water agencies continue to monitor the contamination plume and water supplies to ensure only clean, high-quality water is delivered to homes and businesses.

State agencies have been working near the source areas to remove VOCs that continue to leach into the underlying aquifers.

OCWD's role
For more than a decade, OCWD has been working with elected leaders, regulators, community groups and water agencies to address this contamination issue. OCWD had previously conducted investigations and developed initial plans for a remediation program. This information will be shared with EPA to assist the agency with its own investigation and remediation development process.

OCWD will support the EPA throughout the process to encourage significant involvement and collaboration between elected leaders, water agencies, community groups, and regulators in open and transparent settings. OCWD will continue to work with county, state and federal authorities to ensure the most reliable and cost-effective solutions are put in place.

What's next?
The EPA will initiate a "Remedial Investigation/Feasibility Study." This effort will evaluate the nature and extent of contamination, and identify and evaluate potential remedial actions to prevent further degradation of area groundwater and protect down-gradient drinking water wells.

EPA has promised a robust public participation process and said it plans to meet soon with interested Orange County stakeholders.

One potential result of its investigation is that the EPA may determine that the North Basin contamination site should be added to the National Priorities List – commonly referred to as a Superfund site. This framework is used in states across the country to bring together stakeholders, regulators and elected leaders, and more importantly, responsible parties to clean up contamination and pollution. It has the potential to allow for federal funds, along with monies received from responsible parties, to be used for the cleanup. This will protect the ratepayers from bearing the entire financial burden of cleaning up a problem caused by others.

The contamination took decades to spread and could take approximately 30 years or more to clean up. OCWD will continue to provide information on this issue as it becomes available.