Skip to Content
Questions or Comments: uic@tceq.texas.gov

Class VI Injection Wells: Requesting a Letter of Determination

Definition and jurisdiction of Class VI wells. Obtaining a letter of determination from TCEQ.


On this page:


About Class VI Wells


Definition: Class VI injection wells are used to inject anthropogenic, or man-made, carbon dioxide (CO2) into deep formations for geologic sequestration and storage.


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.


Application for Letter of Determination

Submit one paper copy and one electronic copy on a flash drive of the Class VI application to the TCEQ UIC Permits Section at one of the following addresses:

Mailing address:

Texas Commission on Environmental Quality
Attn: Underground Injection Control (UIC) Permits Section
Radioactive Materials Division
Mail Code 233
P O Box 13087
Austin Texas 78711-3087

Physical address:

Texas Commission on Environmental Quality
Attn: Underground Injection Control (UIC) Permits Section
Radioactive Materials Division
Mail Code 233
12100 Park 35 Circle Building F
Austin Texas 78753

Confidential Materials

We must receive all required information in the Class VI application, including confidential information. Otherwise, we will not consider your application complete and will not be able to issue the 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 by 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 application is incomplete and we need additional information, we will issue a notice of deficiency letter. Once the technical review of the application is complete, we will issue a Letter of Determination to the applicant with a copy to RRC.


More Information