Aquifer Exemptions

​​​​​​​​​​​​​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.


Status of Aquifer Exemptions

Approved Aquifer Exemptions Post-Primacy (1985 - 2009)

​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.

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