Definition of Class VI wells

Class VI wells are used to inject carbon dioxide (CO2) into deep rock formations. This long-term underground storage is called geologic sequestration (GS). Geologic sequestration refers to technologies to reduce CO2 emissions to the atmosphere and mitigate climate change.

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Class VI well requirements are designed to protect underground sources of drinking water (USDWs). Requirements address:

• Siting

• Construction

• Operation

• Testing 

• Monitoring

• Closure

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Requirements for Class VI wells

EPA developed specific criteria for Class VI wells:

• Extensive site characterization requirements

• Injection well construction requirements for materials that are compatible with and can withstand contact with CO2 over the life of a GS project

• Injection well operation requirements

• Comprehensive monitoring requirements that address all aspects of well integrity, CO2 injection and storage, and ground water quality during the injection operation and the post-injection site care period

• Financial responsibility requirements assuring the availability of funds for the life of a GS project (including post-injection site care and emergency response) 

• Reporting and recordkeeping requirements that provide project-specific information to continually evaluate Class VI operations and confirm USDW protection 

Class VI guidance documents

 Review Class VI guidance document from EPA/UIC  

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Class VI Permit Outline

 Review Class VI permit outline from EPA/UIC ​