EPA Proposes Plan to Contain Groundwater Pollution in Orange County

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The U.S. Environmental Protection Agency is rolling out a new plan aimed at stopping the spread of groundwater contamination in one of Orange County's most critical drinking water sources. The proposed interim cleanup plan would install extraction and injection wells to contain and treat the polluted groundwater before it can spread further or reach additional supply wells.

Why it matters

The Orange County Groundwater Basin supplies about 85% of the drinking water for central Orange County, so containing this pollution is crucial to protecting a vital water resource for local communities. Six drinking water wells have already been taken offline due to the contamination risk.

The details

The contamination traces back to past industrial activity that polluted roughly 6.4 square miles of the basin, with pollutants found as deep as 500 feet underground. The EPA's proposal calls for installing about 17 extraction wells to pull contaminated water out of the ground, routing it to a centralized treatment facility, and then sending the cleaned water back underground through another 17 injection wells. Long-term monitoring would track contamination levels, while restrictions would limit groundwater use in the most affected areas.

• The Orange County North Basin site was added to EPA's National Priorities List in 2020.
• The EPA has opened a public comment period on the proposal through February 19, 2026.
• The EPA will host a public meeting on January 29, 2026 to walk through the plan and answer questions.

What’s next

The EPA has opened a public comment period on the proposal through February 19, 2026, and will host a public meeting on January 29, 2026 to walk through the plan and answer questions.