Class VI Injection Wells

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.

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

  • Siting

  • Construction

  • Operation

  • Testing 

  • Monitoring

  • Closure

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  

Class VI Permit Outline

 Review Class VI permit outline from EPA/UIC

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