In its oversight of injection well operations, the highest priority of the Geologic Energy Management Division (CalGEM) is to protect aquifers clean enough to supply water for drinking or agricultural use. CalGEM, the U.S. Environmental Protection Agency (EPA), and the State Water Resources Control Board (SWRCB) have
jointly developed a process to ensure that protection. However, an exemption that allows injection may be granted if an aquifer is not a current or future source of drinking water because it naturally contains petroleum or harmful levels of minerals such as arsenic or boron.
The
Aquifer Exemption Review Process (PDF infographic) begins with CalGEM and SWRCB concurring that an aquifer meets certain criteria. The request for the exemption from the federal Safe Drinking Water Act (SWDA) is sent to the EPA, which makes the final determination.
EPA Correspondence and Guidance Documents
On March 23, 2020,
CalGEM and SWRCB sent an update to the EPA on California’s ongoing corrective review of underground injection well information. The continuing effort is to make sure that California’s oil and gas operations are being conducted in full compliance with SDWA .
Related Information
The link below is to a list of issued well permits that may currently have a corresponding well injecting into an aquifer potentially needing an aquifer exemption, pursuant to the EPA's request.
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The list is best understood as a list of well permits, rather than wells. Wells can be proposed and permitted without ever being drilled or converted to an injection well. Even where a well has been drilled, it may already have been plugged and abandoned or issued other orders preventing injection. Determining the current status of the wells listed here is part of CalGEM’s February 6, 2015, response to the US EPA. This list was generated by identifying one or both of the following characteristics:
- The permit is for a well located outside the productive limits of a field as those limits were identified in the State’s Primacy application to the US EPA;
- The permit is for a well injecting within the productive limits but into multiple zones, one of which may not be exempted by the Memorandum of Agreement (MOA) with the US EPA. CalGEM acknowledges that many of these wells may not need an aquifer exemption, but a formal determination cannot be made until an evaluation, of the specific well(s) and injection zone(s), is completed.
Please note that the evaluation of these well permits has begun and the list continues to change. However, to be consistent with the US EPA’s letter to CalGEM dated December 22, 2014, and CalGEM’s response on February 6, 2015, the list contains the permitted wells into non-hydrocarbon-producing zones as of August 2014, and a list of the enhanced oil recovery permitted wells as of October 2014. CalGEM will update the list periodically.
Memoranda of Agreement (MOA)
Primacy Agreements and Related Documents
Underground Injection Control, MOA, September 1982
Additional Information
Underground Injection Control (UIC)
UIC Application Guidance
Application for Primacy - Class II Injection Wells
