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• Rule Summary
• Rule History

Rule Summary

On Dec 10, 2010 EPA issued a rule that established a new well class, Class VI.  The Class VI rule established minimum technical criteria to protect underground source of drinking water from the long-term subsurface storage of carbon dioxide (CO2).  The technical criteria covered by the Class VI rule include:

• Permitting
  • Geologic site characterization  
  • Area of review (AOR) and corrective action
  • Financial responsibility 
• Well construction 
• Operation 
  • Mechanical integrity testing (MIT)
  • Monitoring 
• Well plugging 
• Post-injection site care (PISC)
• Site closure

​The rule became effective on September 7, 2011 after a 270 day period during which states could apply for and receive primary enforcement responsibility (primacy).  EPA directly implements the Class VI Program in all states, tribes, and territories except North Dakota, which received Class VI primacy in April 2018.   

Review the supporting documents to learn more about the final rule for UIC Class VI wells.

Review the federal register notice for the final rule for UIC Class VI wells.

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Rule History

In October 2007 EPA announced that the Agency planned to propose regulations to ensure consistency in permitting full-scale geologic sequestration projects. Public stakeholder workshops were held subsequent to that announcement to inform the regulatory development process.

EPA published the proposed rule for for Class VI wells in July 2008.  The public comment period opened when the Federal Requirements Under the Underground Injection Control (UIC) Program for Carbon Dioxide (CO2) Geologic Sequestration (GS) Wells Proposed Rule was published. The comment period closed December 24, 2008.

EPA held two public hearings to solicit public comment on the proposed regulations for geologic sequestration of carbon dioxide. The first was held on September 30, 2008 at EPA’s Region 5 Office in Chicago, IL.  The second was held on October 2, 2008 in Denver, CO at the Colorado Convention Center.

Review the supporting documents to learn about the proposed rule for UIC Class VI wells.