This document contains the following sections: Section 1 provides background on the federal UIC Program and summarizes the requirements of the GS Rule. Section 2 provides guidance to states, tribes, and territories on applying for UIC Class VI Program primacy. Independent Primacy. Under the UIC GS Rule, states have the option to seek primacy for Class VI injection wells independent of other UIC injection well classes under SDWA Section 1422. Section 2 differentiates between the requirements for submitting: (1) A New UIC Program application for states that currently do not have an existing UIC Program, or states that have primacy under SDWA Section 1425 only (e.g., the Class II injection well program); and (2) A UIC Program Revision application to add the new UIC Class VI requirements to an existing state UIC Program operating under Section 1422 of SDWA. Regulatory Development. Section 2 also discusses some considerations while drafting state, tribal, or territorial regulations governing Class VI injection wells that will be evaluated as part of the EPA primacy application review and approval process, including determinations on the stringency and equivalency of state and federal regulations. Section 3 provides information and considerations that UIC Program Directors may employ in evaluating proposed Class VI injection well permit applications and with implementing the UIC Class VI GS Rule. Permit Application Information. Section 3 provides information for the UIC Program Director to use in evaluating Class VI permit applications. This includes information that the Program Director may receive from owners or operators with their permit applications, including the five (5) required project plans, and approaches to interpreting and evaluating this information and/or data, areas of Program Director discretion, and suggestions for when the Director may request additional information. Additional Considerations. Section 3 also describes other program implementation topics such as Class VI permitting, the required re-permitting of existing Class I, II, or V injection wells as Class VI; environmental justice (EJ) considerations; public involvement and outreach associated with GS projects; and interstate communication and coordination efforts. The appendices to this manual include a crosswalk for comparing federal and state Class VI requirements, sample letters and notifications as examples of primacy application elements, hypothetical primacy and permitting scenarios, and a recommended checklist for organizing the submitted Class VI injection well permit application information during an evaluation.