Oil Fields Issues

The Central Valley Water Board has undertaken a significant effort to address issues associated with unlined impoundments (ponds) used to dispose of water produced as a by-product of oil production (produced water). There are an estimated 933 of these ponds within the Central Valley. If not managed properly, unlined ponds can pose a risk to groundwater quality. Staff is in the process of evaluating current and past discharges to verify whether they are permitted and in compliance with State regulations. If not, enforcement will be taken to require the ponds to come into compliance or close. If beneficial uses of groundwater have been impaired, investigation and remediation will be required.

The Central Valley Water Board is also investigating potential water quality issues associated with the underground injection of produced water (injection wells); discharges of drilling fluids from oil well drilling and workover activities; and oil well stimulation (e.g., hydraulic fracturing).