Class VI Injection Wells: Requesting a Letter of Determination

On this page:

• About Class VI Wells
• Standards for Letter of Determination
• Requesting a Letter of Determination
• Confidential Materials
• Application Review
• EASiTool
• More Information

About Class VI Wells

Jurisdiction: The Railroad Commission of Texas regulates Class VI injection wells.

Standards for Letter of Determination

A person submitting a Class VI permit application to the RRC is required to include with the application a Letter of Determination from TCEQ.

To obtain a Class VI permit, the Letter of Determination from TCEQ must conclude the following activities will not impact or interfere with any previous or existing Class I injection well, including any associated waste plume, or any other injection well authorized or permitted by the commission:

• Drilling and operating an anthropogenic CO2 injection well for geologic storage.
• Constructing or operating a geologic storage facility.

Requesting a Letter of Determination

To request a Letter of Determination, submit one paper copy and one electronic copy on a flash drive of the complete Class VI permit application including attachments, appendices and references, and subsequent application revisions. In addition to the Class VI permit application, one paper copy and one electronic copy of supplemental information requested in Supplemental Information Requirements for Class VI Project Reviews by TCEQ UIC Permits Section must be provided for review.  Submit the application and supplemental information to the TCEQ UIC Permits Section at one of the following addresses:

Mailing address:

Physical address:

Confidential Materials

We must receive all required information in the Class VI permit application and supplemental information, including confidential information. Otherwise, we will not be able to complete our review or issue a Letter of Determination.

Guidelines to Protect Confidential Materials

If requested, TCEQ must provide a copy of each application to other agencies and to interested persons while safeguarding confidential material from becoming public. Therefore, TCEQ requests that the applicant:

• Be prudent in designating material as confidential.
• Submit confidential materials only when the information is required in the application. 

Requirements to Submit Confidential Materials

• The confidential information should be submitted as a separate document or binder with each page conspicuously marked "Confidential."
• The confidential information should be described in non-confidential terms throughout the application with references to the separate "Confidential” document or binder.

Application Review

If the Class VI permit application and supplemental information is insufficient and we need additional information, we will issue a request for additional information letter. Once the technical review of the application is complete and we determine that the Class VI activities will not impact or interfere with any previous or existing Class I injection well, including any associated waste plume, or any other injection well authorized or permitted by the commission, we will issue a Letter of Determination to the applicant with a copy to RRC.

EASiTool

Below is the link to EASiTool, which TCEQ currently uses for pressure front and sensitivity analysis estimation and validation:

https://easitool5-pe1pac0l4h.streamlit.app/

Any technical questions can be discussed with Seyyed A. Hosseini, Ph.D., Research Professor, Bureau of Economic Geology, University of Texas at Austin at seyyed.hosseini@beg.utexas.edu.  

More Information

• RRC Geologic Storage of CO₂ provides detailed information and steps on Class VI wells and applying for a permit.

• EPA Final Class VI Guidance Documents provides additional documentation for Class VI well owners or operators in complying with Class VI regulations.