# EPA-administered program.
**AGENCY:**
Environmental Protection Agency (EPA).
**ACTION:**
Final rule.
**SUMMARY:**
The U.S. Environmental Protection Agency (EPA) is approving an application from the State of Arizona (the State) that requests primary enforcement responsibility (primacy) for Class I-VI injection wells under the Safe Drinking Water Act (SDWA) section 1422. The EPA's approval of the State's UIC program primacy application will allow the Arizona Department of Environmental Quality (ADEQ) to authorize underground injection for all underground injection wells regulated under the SDWA within the State's jurisdiction and ensure compliance with UIC program requirements. The EPA will remain the permitting authority for all well classes on Indian lands within the State, except for Class II wells on Navajo Indian lands for which the EPA has granted the Navajo Nation primacy for the SDWA Class II UIC program.
**DATES:**
This final rule is effective on October 15, 2025. The incorporation by reference of certain material listed in this rule is approved by the Director of the Federal Register as of October 15, 2025. For judicial purposes, this final rule is promulgated as of October 15, 2025.
**ADDRESSES:**
The EPA has established a docket for this action under Docket ID No. EPA-HQ-OW-2025-0087. All documents in the docket are listed on the *http://www.regulations.gov* website. Although listed in the index, some information is not publicly available, *e.g.,* confidential business information (CBI) or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, is not placed on the internet and will be publicly available only in hard copy form. Publicly available docket materials are available electronically through *http://www.regulations.gov.*
**FOR FURTHER INFORMATION CONTACT:**
Mary Hastings Puckett, Drinking Water Infrastructure Development Division, Office of Ground Water and Drinking Water (4606M), Environmental Protection Agency, 1200 Pennsylvania Ave. NW, Washington, DC 20460; telephone number: (202) 564-1525; or Kate Rao, Water Division, Groundwater Protection Section (WTR-4-2), Environmental Protection Agency, Region 9, 75 Hawthorne Street, San Francisco, CA 94105; telephone number: (415) 972-3533. Both can be reached by emailing *[email protected].*
**SUPPLEMENTARY INFORMATION:**
**Table of Contents**
I. Introduction
A. Federal UIC Program and Primary Enforcement Authority (Primacy)
B. Class I-VI Wells Under the UIC Program
II. Legal Authorities
III. Arizona's Application for UIC Primacy
A. Background
B. Public Participation Activities Conducted by Arizona
C. Summary of the EPA's Comprehensive Evaluation
D. Public Participation Activities Conducted by the EPA
IV. Public Comments and the EPA's Response
A. Public Comments
B. The EPA's Response to Comments
V. The EPA's Action
A. Incorporation by Reference
B. The EPA's Oversight
VI. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Executive Order 14192: Unleashing Prosperity Through Deregulation
C. Paperwork Reduction Act (PRA)
D. Regulatory Flexibility Act (RFA)
E. Unfunded Mandates Reform Act (UMRA)
F. Executive Order 13132: Federalism
G. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments
H. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks
I. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use
J. National Technology Transfer and Advancement Act (NTTAA)
K. Congressional Review Act (CRA)
VII. References
**I. Introduction**
**A. Federal UIC Program and Primary Enforcement Authority (Primacy)**
The SDWA protects public health by regulating the nation's public drinking water supply, including both surface and groundwater sources. Among other things the SDWA requires the EPA to develop minimum requirements for effective State and Tribal UIC programs to prevent underground injection of fluids (such as water, wastewater, brines from oil and gas production, and carbon dioxide) from endangering underground sources of drinking water (USDWs). In general, USDWs are aquifers or parts of aquifers that supply a public water system or contain enough groundwater of sufficient quality to supply a public water system. See 40 CFR 144.3 (defining USDW).
The EPA's UIC program regulates various aspects of injection. These include technical aspects throughout the lifetime of the project from site characterization, construction, operation, and testing and monitoring through site closure, as well as permitting, site inspections, and reporting to ensure well owners and operators comply with UIC permits and regulations.
SDWA section 1421 directs the EPA to establish requirements that States, territories, and authorized Tribes must meet to be granted primary enforcement responsibility or “primacy” for a UIC program. 42 U.S.C. 300h. SDWA section 1422 provides that an applicant seeking primacy for a UIC program must demonstrate to the EPA that the applicant's proposed UIC program meets the applicable requirements promulgated by the EPA pursuant to section 1421 for protecting USDWs. 42 U.S.C. 300h-300h-1. An applicant must demonstrate, among other things, jurisdiction over underground injection and that it possesses the administrative, civil, and criminal enforcement authorities required by the EPA's implementing regulations. See 40 CFR part 145, subpart B. After the EPA approves a State for UIC program primacy, the State's UIC program may be revised with EPA approval. See 40 CFR 145.32.
The EPA evaluates each primacy application in accordance with SDWA section 1422 and the EPA's implementing regulations to determine whether the State has satisfactorily demonstrated that, after reasonable notice and public hearings, it has adopted and will implement a UIC program that meets the requirements of the SDWA regulations at 40 CFR parts 144, 145, and 146.
In this final rule, the EPA is approving Arizona's primacy application to administer the UIC program for six classes of wells (Classes I-VI) in the state. EPA's approval is based on the Agency's determination that the application meets all applicable requirements for approval under SDWA section 1422 and the EPA's implementing regulations and that the State is capable of administering a UIC program in a manner consistent with the SDWA and applicable UIC regulations. The EPA will remain the permitting authority for all UIC well classes on Indian land within the State, except for Class II wells on Navajo Indian lands for which EPA has granted the Navajo Nation primacy for the SDWA Class II UIC program. The EPA will oversee Arizona's administration of the State's UIC program as authorized under the SDWA.
**B. Class I-VI Wells Under the UIC Program**
The UIC program consists of six classes of injection wells. Each well class is based on the type and depth of the injection activity and the potential for that injection activity to result in the endangerment of a USDW. Class I wells are used to inject wastes into deep isolated rock formations. Class II wells are used to inject fluids related to oil and natural gas production, primarily to enhance recovery of oil and gas or to dispose into rock formations wastewater associated with oil or gas production. Class III wells are used to inject fluids to dissolve and extract minerals. Class IV wells are used to inject hazardous and radioactive wastes into or above USDWs and are only allowed as part of an EPA- or State-authorized groundwater clean-up action. Class V wells are used to inject non-hazardous fluids underground, typically into or above a USDW, and range from simple shallow wells to complex experimental injection technologies. Most Class V wells are “low-tech”, depending on gravity to drain fluids directly below the land surface and include dry wells, cesspools, and septic system leach fields. Class VI wells are used to inject carbon dioxide into deep rock formations for the purpose of long-term underground storage, also known as geologic sequestration. 40 CFR 144.6.
The UIC program provides multiple safeguards that work together to protect USDWs and human health from injection activities. To operate an injection well, operators must receive authorization by permit, or by rule in certain circumstances, through the UIC program. Operators must obtain a permit that authorizes injection in accordance with specific statutory and regulatory conditions. A draft of each permit is made available for public comment before the decision is made whether to issue a final permit. Qualifying Class V wells that meet certain requirements can be authorized by rule after the operator submits required information describing the injection activity, location, operating status, and operator contact information. All wells must be operated according to applicable UIC program requirements for the injection activity.
**II. Legal Authorities**
The statutory authority for this final rule is SDWA sections 1422 and 1450, 42 U.S.C. 300h-1 and 300j-9.
SDWA section 1421 requires the EPA promulgate requirements for effective State UIC programs to prevent underground injection activities that endanger USDWs. 42 U.S.C. 300h. SDWA section 1422 requires that applicants seeking primacy approval demonstrate that they have adopted (after notice and public hearing) and will implement a UIC program which meets the requirements that the EPA promulgated under SDWA section 1421. 42 U.S.C. 300h-1.
The EPA has promulgated regulations setting forth the applicable procedures and substantive requirements for applicants seeking primacy approval for UIC programs under SDWA section 1422. The regulations in 40 CFR part 144 outline general program requirements that States must meet to obtain primacy. The regulations in 40 CFR part 145 specify the procedures the EPA will follow in approving, revising, and withdrawing UIC programs and outlines the elements and provisions that an applicant must include in its application for primacy. 40 CFR part 145 also includes requirements for State UIC permitting programs (by reference to certain provisions of 40 CFR parts 124 and 144), compliance evaluation programs, enforcement authority, and the sharing of information between the EPA and the State. The regulations in 40 CFR part 146 contain the technical criteria and standards applicable to each well class.
**III. Arizona's Application for Primacy**
**A. Background**
On February 16, 2024, Arizona applied to the EPA under SDWA section 1422 to administer a UIC program for Class I-VI injection wells located within the State, except those located on Indian lands. Arizona's requirements for UIC wells would be codified and implemented in lieu of the Federal UIC requirements currently in effect in the State. See 40 CFR part 147, subpart D. Arizona's UIC program primacy application includes a letter from the Governor requesting UIC program primacy approval, a complete description of the State's UIC program, an Attorney General's statement, copies of all applicable State statutes and regulations, a summary and the results of the State's public-participation activities, and a Memorandum of Agreement (MOA) between Arizona and the EPA's Region 9 Office. The EPA reviewed the application for completeness and performed a technical and legal evaluation of the application materials to assess and confirm that Arizona's proposed UIC program meets Federal requirements.
**B. Public Participation Activities Conducted by Arizona**
**1. UIC Program Development Stakeholder Engagement**
In order to have State regulatory authority in place prior to seeking EPA approval of its UIC program, ADEQ conducted stakeholder outreach and engagement to inform the general public, the regulated community, and Tribes of ADEQ's rule development process and to explain and present early drafts of the applicable State UIC rules. ADEQ held nine general stakeholder and three Tribal consultation events from December 2017 to October 2019. ADEQ received and considered hundreds of comments from the regulated community and other stakeholders on these early drafts of the State rules.
**2. State Rulemaking**
On October 1, 2021, ADEQ filed a notice of imminent SDWA-UIC rulemaking with the Arizona Secretary of State asserting its intent to adopt the UIC program. On January 7, 2022, ADEQ filed three notices of proposed rulemaking for licensing time frames and UIC program rules and fees, which were followed by a comment period of more than 30 days. ADEQ held a public hearing on February 14, 2022, the final day of the written comment period. ADEQ received a total of 77 discrete written and oral comments on the proposed rules. Commenters shared concerns on licensing time frames, fees, drywells, underground storage or recharge facilities, UIC septic regulation, program scope or jurisdiction, and Tribal consultation, among other topics. ADEQ considered all the comments and adjusted the proposed rules as summarized in the responsiveness summary. The Arizona UIC regulations became effective on September 6, 2022.
**3. Proposal To Request UIC Program Primacy**
On October 15, 2023, ADEQ published notice in two Arizona newspapers, through its website, and by email distribution to stakeholders, seeking public comment on the State's proposed application for primacy for the UIC program. ADEQ held a public comment period from October 15, 2023, to November 20, 2023, on the State's intent to seek primacy. ADEQ also held a virtual public hearing on November 20, 2023. ADEQ received 1 oral comment and 21 discrete written comments. The commenters shared concerns with the primacy application, including language regarding aquifer exemptions, permit transition upon primacy, Federal UIC policies, permit templates, regulatory differences between the State's Aquifer Protection Program and the SDWA UIC program, and minor editorial comments such as incorrect cross references. These comments were considered and addressed by ADEQ as summarized in the responsiveness summary and did not result in any significant changes to the proposed primacy application.
Documentation of Arizona's public participation activities, including comments received and responses by ADEQ, can be found in EPA Docket ID No. EPA-HQ-OW-2025-0087.
**C. Summary of the EPA's Comprehensive Evaluation**
The EPA evaluates primacy applications in accordance with SDWA section 1422 and the agency's implementing regulations to determine whether an applicant has satisfactorily demonstrated that it has adopted, after reasonable notice and public hearings, and will implement, a UIC program that meets applicable regulatory requirements. 42 U.S.C. 300h-1(b)(1)(A)(i). The EPA conducted a comprehensive technical and legal evaluation of Arizona's primacy application to determine whether the State's UIC program—including statutes and regulations, program description, Attorney General statement, MOA, and documentation of public participation—demonstrates that Arizona has met the requirements of SDWA section 1422. Upon review, the EPA determined that Arizona has adopted and will implement a UIC program that meets the requirements of 40 CFR parts 144, 145, and 146.
The EPA evaluated Arizona's UIC program description for consistency with 40 CFR 145.23, which lists all the information that must be submitted as part of the program description. The EPA's evaluation of the UIC program description included reviewing the scope, structure, coverage, and processes of the State's program. The EPA assessed Arizona's permitting, administrative, and judicial review procedures, as well as the State's permit application, reporting, and manifest forms. The EPA also reviewed the State's compliance evaluation program and enforcement authorities and the State's demonstration that its UIC program will have adequate in-house staff or access to contractor support for technical areas including site characterization, modeling, well construction and testing, financial responsibility, and regulatory and risk analysis.
The EPA evaluated Arizona's Attorney General's statement for consistency with 40 CFR 145.24. In an Attorney General's statement, the State's top legal officer affirms that applicable statutes, regulations, and judicial decisions demonstrate adequate authority to administer the UIC program as described in the program description and consistent with the EPA's regulatory requirements for UIC programs. The EPA confirms that the Arizona Attorney General's statement certifies that Arizona's environmental audit privilege, which protects certain self-reported information, will not affect the ability of the State to meet the enforcement and information gathering requirements under the SDWA, nor will it prevent the public from obtaining information about noncompliance or prevent the public from bringing citizen suits under the SDWA.
The EPA determined that the MOA, which was duly signed by EPA Region 9 and ADEQ, meets the requirements at 40 CFR 145.25. The MOA is the central agreement setting the provisions and arrangements between the State and the EPA concerning the administration, implementation, and enforcement of the State UIC program. The EPA's evaluation includes ensuring that the MOA contains the necessary provisions pertaining to agreements on coordination, permitting, compliance monitoring, enforcement, and EPA oversight.
Arizona has demonstrated that it has the legal authority to implement all UIC permit requirements found in 40 CFR 145.11. Arizona's UIC permitting provisions, established under SDWA section 1422, meet the minimum Federal requirements in 40 CFR parts 124 and 144 through 146. The State has incorporated necessary procedures pursuant to 40 CFR 145.12 to support a robust UIC compliance evaluation program. Additionally, Arizona has the necessary administrative, civil, and criminal enforcement authorities pursuant to 40 CFR 145.13. Arizona's UIC regulations regarding permitting, inspection, operation, and monitoring meet requirements in 40 CFR parts 145 and 146. Arizona's reporting and recordkeeping requirements meet the requirements in 40 CFR 144.54 and 40 CFR part 146.
As a result of this comprehensive review, the EPA approves Arizona's primacy application based on the Agency's determination that the application meets all applicable requirements for primacy approval under SDWA section 1422 and that the State has demonstrated that it is prepared to implement its UIC program in a manner consistent with the SDWA and all applicable UIC regulations.
**D. Public Participation Activities Conducted by the EPA**
On February 29, 2024, the EPA Region 9 Water Division Director sent a letter via email to Arizona Tribal leaders offering an opportunity for Government-to-Government consultation on Arizona's application for primacy to administer the UIC program. On March 14, 2024, the EPA Region 9 hosted a Tribal informational meeting and listening session for Arizona's application for primacy to administer the UIC Program. One Tribe, the Navajo Nation, attended the informational meeting and followed up with a letter of support for Arizona administering the UIC program. Another Tribe, the Gila River Indian Community (GRIC), requested that the EPA meet with them separately to present and discuss the information shared at the meeting on March 14, 2024. The EPA met with GRIC representatives on March 22, 2024. GRIC asked questions about differences between the implementation and oversight of the Federal versus State UIC program, and the primacy approval process and EPA responded.
On May 19, 2025, the EPA published a proposed rulemaking in the *Federal Register* (90 FR 21264) to approve Arizona's application to implement a UIC program for all injection well classes within the State. The proposal established a public comment period that closed on July 3, 2025. The EPA held a public hearing on June 25, 2025, that participants could attend virtually, as well as by phone. The EPA published notice of the hearing on the EPA's website, in the *Arizona Daily Star* and the *Arizona Republic* newspapers, and sent an email notification to each of Arizona's federally recognized Tribal leaders.
**IV. Public Comments and the EPA's Response**
**A. Public Comments**
During the public comment period, the EPA received eleven written comments and two oral comments on the proposal from individuals and stakeholder organizations, including GRIC, the Ground Water Protection Council, the Grand Canyon Chapter of the Sierra Club, the Consumer Energy Alliance, the American Petroleum Institute, the American Mining Association, and the Arizona Chamber of Commerce and Energy.
The EPA considered these comments in the development of this final rule. All comments are available as part of the public record and can be accessed through the EPA's docket (ID No. EPA-HQ-OW-2025-0087). Documentation of the EPA's public participation activities, including comments received and the EPA's comment response document, can also be found in the docket (ID. No. EPA-HQ-OW-2025-0087).
**B. The EPA's Response to Comments**
The EPA received comments both supporting and opposing the proposed approval of UIC program primacy for the State of Arizona, as well as some comments outside the scope of the primacy approval action.
Commenters in support of Arizona's UIC program primacy approval stated that ADEQ's UIC rules meet or exceed the EPA's UIC requirements, that ADEQ has conducted adequate outreach and engagement related to its UIC primacy application, and that the State's request is consistent with the principles of cooperative federalism outlined in the five pillars of the EPA Administrator's Powering the Great American Comeback Initiative. They also stated that Arizona's primacy application shows that the State takes program compliance and enforcement seriously. They stated that Arizona is heavily invested in protecting its drinking water sources, as shown by how Arizona water providers use Managed Aquifer Recharge (MAR)—a water management technique to store available freshwater underground and which often utilizes UIC Class V injection wells. They commented that ADEQ has a better understanding of the State and local needs, is more readily accessible to stakeholders, has intimate knowledge of historic UIC operations, has an extensive knowledge and understanding of the State's aquifers and geology, and has demonstrated a strong commitment to transparency through extensive stakeholder engagements. Lastly, commenters stated that with ADEQ's dedicated UIC staff positions, the State has the capacity for timely review and action on UIC permit applications and rule applications and further, that the State's UIC program includes licensing time frame requirements for ADEQ, which provide predictability and certainty with respect to the timing of permit decisions.
Commenters opposing Arizona's UIC program primacy approval stated concerns about vulnerable communities in low-income and rural areas as well as those on Tribal lands who may be overburdened by pollution. One commenter stated that permitting actions could impact the groundwater quality on Tribal lands and impact cultural resources located off Tribal lands. Commenters asserted that Arizona and ADEQ have been underfunded and, therefore, lack the staffing and resources needed to stand up to powerful polluters, to regulate carbon capture and storage projects safely and effectively, and to protect groundwater quality. Commenters also raised concerns related to Arizona's limited water supply and potential threats posed by UIC wells. Lastly, commenters stated concerns about ADEQ's current online tools and public information systems and questioned whether they are adequate to track and evaluate potential threats from injection wells.
Comments received outside the scope of this primacy approval action included concerns about fracking activity, the direct and indirect costs of producing and burning fossil fuels, the lack of international considerations, whether the EPA has the authority to “delegate” the UIC program to a State, and the fitness of leadership within the EPA. The EPA has noted and addressed all topics, including out-of-scope topics, in the Agency's response to comments document included in the docket (ID. No. EPA-HQ-OW-2025-0087).
**V. The EPA's Action**
**A. Incorporation by Reference**
The EPA is approving the State of Arizona's UIC program primacy application for regulating Class I-VI injection wells in the State, except for those located on Indian lands. This action would amend 40 CFR 147.150 and 147.151 and incorporate by reference Arizona's EPA-approved statutes and regulations that contain standards, requirements, and procedures applicable to UIC well owners or operators within the State. Any provisions incorporated by reference, as well as all permit conditions issued pursuant to such provisions, are enforceable by the EPA pursuant to SDWA section 1423, 42 U.S.C. 300h-2, and 40 CFR 147.1(e).
The EPA compiled the applicable Arizona statutes and regulations to be incorporated by reference into 40 CFR 147.150 in a document titled “Arizona SDWA § 1422 Underground Injection Control Program Statutes and Regulations to be Incorporated by Reference,” dated March 24, 2025. This compilation is publicly available in the EPA's Docket No. EPA-HQ-OW-2025-0087 for this rulemaking *https://www.regulations.gov.* The EPA will codify a table in 40 CFR 147.150 listing the EPA-approved Arizona Statutes and Regulations for Well Classes I-VI that will be incorporated by reference. Additionally, the EPA lists the other Arizona statutes and regulations containing standards and procedures that constitute elements of the State's approved UIC program that do not apply directly to owners or operators in the amendment to 40 CFR 147.150. In accordance with 40 CFR 147.1(c), these other statutes and regulations are not incorporated by reference.
**B. The EPA's Oversight**
The EPA will oversee Arizona's administration of its UIC program, including by requiring quarterly reports on instances of permittee non-compliance and annual UIC performance reports pursuant to 40 CFR 144.8. The MOA between the EPA Region 9 and ADEQ specifies that the EPA will oversee the State's administration of the UIC program on a continuing basis to assure that such administration is consistent with the program MOA, the SDWA and implementing regulations, UIC grant agreements, and other applicable requirements.
**VI. Statutory and Executive Order Reviews**
Additional information about these statutes and Executive orders can be found at: *https://www.epa.gov/laws-regulations/laws-and-executive-orders.*
**A. Executive Order 12866: Regulatory Planning and Review**
This action is exempt from review under Executive Order 12866, because the Office of Management and Budget (OMB) has exempted, as a category, the approval of State UIC programs.
**B. Executive Order 14192: Unleashing Prosperity Through Deregulation**
Executive Order 14192 does not apply because actions that approve State UIC Programs are exempted from review under Executive Order 12866.
**C. Paperwork Reduction Act (PRA)**
This action will not impose an information collection burden under the PRA. OMB has previously approved the information collection activities contained in the existing regulations and has assigned OMB control number 2040-0042. Reporting or recordkeeping requirements will be based on Arizona's UIC regulations, and the State of Arizona is not subject to the PRA.
**D. Regulatory Flexibility Act (RFA)**
I certify that this action will not have a significant economic impact on a substantial number of small entities under the RFA. This action will not impose any additional burdens on small entities as this action codifies a State program already in effect and transfers primary implementation authority from the EPA to a State program with substantially the same requirements.
**E. Unfunded Mandates Reform Act (UMRA)**
This action does not contain an unfunded mandate as described in UMRA, 2 U.S.C. 1531-1538, and does not significantly or uniquely affect small governments. The action imposes no enforceable duty on any State, local, or Tribal governments or the private sector. The EPA's approval of Arizona's UIC program will not constitute a Federal mandate because there is no requirement that a State establish a UIC regulatory program and the program is a State program, rather than a Federal program.
**F. Executive Order 13132: Federalism**
This action does not have federalism implications. It will not have substantial direct effects on the States, on the relationship between the National Government and the States, or on the distribution of power and responsibilities among the various levels of government.
**G. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments**
This action does not have Tribal implications as specified in Executive Order 13175. This action contains no Federal mandates for Tribal governments and does not impose any enforceable duties on Tribal governments. Thus, Executive Order 13175 does not apply to this action.
**H. Executive Order 13045: Protection of Children From Environmental Health and Safety Risks**
The EPA interprets Executive Order 13045 as applying only to those regulatory actions that concern environmental health or safety risks that the EPA has reason to believe may disproportionately affect children, per the definition of “covered regulatory action” in section 2-202 of the Executive Order. This action is not subject to Executive Order 13045 because it approves a State program.
**I. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use**
This action is not subject to Executive Order 13211 because it is not a significant regulatory action under Executive Order 12866.
**J. National Technology Transfer and Advancement Act (NTTAA)**
This rulemaking does not involve technical standards.
**K. Congressional Review Act (CRA)**
This final rule is subject to the CRA, and the EPA will submit a rule report to each House of the Congress and to the Comptroller General of the United States. This action is not a “major rule” as defined by 5 U.S.C. 804(2).
**VII. References**
Attorney General's Statement, signed by the Assistant Attorney General, Office of the Arizona Attorney General, September 5, 2024.
Letter from Governor of Arizona to Regional Administrator, EPA Region 9, February 16, 2024.
Memorandum of Agreement between the State of Arizona Department of Environmental Quality and the Environmental Protection Agency, Region 9, signed by the EPA Regional Administrator on March 24, 2025.
Notice of Nomination of Karen Peters to serve as Director of Environmental Quality, signed by Governor Katie Hobbs, February 19, 2025.
Underground Injection Control State of Arizona Primacy Application, Copies of all applicable State statutes and regulations, including those governing State administrative procedures, drafted by Arizona Department of Environmental Quality. March 10, 2025.
Underground Injection Control Primacy Application, Program Description “Arizona Department of Environmental Quality Underground Injection Control Program Description 40 CFR 145.23.” March 2025.
Underground Injection Control State of Arizona Primacy Application, Public Participation Showing, drafted by Arizona Department of Environmental Quality, February 18, 2025.
U.S. Environmental Protection Agency. Proposed “Arizona SDWA § 1422 Underground Injection Control Program Statutes and Regulations to be Incorporated by Reference.” March 25, 2025. Office of Water.
U.S. Environmental Protection Agency. Arizona UIC Primacy Tribal Consultation Offer Letter. February 29, 2024.
U.S. Environmental Protection Agency. Tribal Informational Meeting and Listening Session. Arizona's Application for Primacy to Administer the Underground Injection Control Program. USEPA Region 9 Groundwater Protection Section—Slide Presentation March 14, 2024.
**List of Subjects in 40 CFR Part 147**
Environmental protection, Incorporation by reference, Indian—lands, Intergovernmental relations, Reporting and recordkeeping requirements, Water supply.
Lee Zeldin,
Administrator.
For the reasons set forth in the preamble, the EPA hereby amends 40 CFR part 147 as follows:
**PART 147—STATE, TRIBAL, AND EPA-ADMINISTERED UNDERGROUND INJECTION CONTROL PROGRAMS**
**40 CFR Part 147**
1. The authority citation for part 147 continues to read as follows:
**Authority:**
42 U.S.C. 300f *et seq.;* and 42 U.S.C. 6901 *et seq.*
**40 CFR Part 147**
2. Add § 147.150 to read as follows:
§ 147.150
The UIC program for Classes I, II, III, IV, V and VI wells in the State of Arizona, except those on Indian lands, is the program administered by the Arizona Department of Environmental Quality, approved by the EPA pursuant to section 1422 of the SDWA. The effective date of this program is October 15, 2025. The UIC program for Classes I, II, III, IV, V and VI wells in the State of Arizona, except those located on Indian lands, consists of the following elements, as submitted to the EPA in the State's primacy application.
(a) *Incorporation by reference.* The requirements set forth in the State statutes and regulations approved by the EPA in “Arizona SDWA § 1422 Underground Injection Control Program Statutes and Regulations to be Incorporated by Reference”, dated March 24, 2025, and listed in table 1 to this paragraph (a), are hereby incorporated by reference and made a part of the applicable UIC program under the SDWA for the State of Arizona. The Director of the Federal Register approves this incorporation by reference in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies of the State of Arizona's statutes and regulations that are incorporated by reference may be obtained from the State of Arizona Research Library located at 1901 West Madison, Phoenix, Arizona 85009. Copies of the State of Arizona's statutes and regulations that are incorporated by reference may be inspected at the U.S. Environmental Protection Agency, Region 9, 75 Hawthorne Street, San Francisco, CA 94105 and the U.S. Environmental Protection Agency, Water Docket, EPA Docket Center (EPA/DC), EPA WJC West, Room 3334, 1301 Constitution Ave. NW, Washington, DC 20004. If you wish to obtain materials from the EPA Regional Office, please call (415) 972-3533, or from the EPA Headquarters Library, please call the Water Docket at (202) 566-2426. You may also view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit *www.archives.gov/federal-register/cfr/ibr-locations* or email *[email protected].*
| State citation | Title/subject | State effective date | EPA approval date |
| --- | --- | --- | --- |
| Arizona Revised Statute (ARS) 49-257.01 (B) and (C) | Underground injection control permit program; permits; prohibitions; rules | September 24, 2022 | September 15, 2025. |
| ARS 49-263 (A), (E), and (I) | Criminal violations; classification; definition | August 3, 2018 | September 15, 2025. |
| ARS 49-921 | Definitions | April 29, 1993 | September 15, 2025. |
| ARS 13-105.30 | Definitions | April 14, 2011 | September 15, 2025. |
| Arizona Administrative Code Title 18, Chapter 9, Article 6 | Underground Injection Control | September 6, 2022 | September 15, 2025. |
(b) *Other laws.* The following statutes and regulations although not incorporated by reference, also are part of the approved State-administered program:
(1) A.R.S. section 1-211 (General Rules of Statutory Construction);
(2) A.R.S. sections 13-107, 801, and 803 (Criminal Code);
(3) A.R.S. sections 18-106 (Information Technology);
(4) A.R.S. sections 41-1001, 1001.02, 1002, 1003 through 1010, 1011 through 1013, 1021 through 1067, 1072 through 1093.07, and 2051 (Administrative Procedure);
(5) A.R.S. sections 44-7001 through 7061 (Electronic Transactions);
(6) A.R.S. sections 49-104, 203, 205, 208, 224, 250, 257, 257.01(A) and (D), 261-262, 263 (B-D) and (F-H), 264, 265, 321 through 324, 922, and 1403 (The Environment);
(7) A.A.C. R18-1-501 through 525 and Table 10 (Licensing Timeframes);
(8) A.A.C. R18-9-103, C301 through C304, and E323 (Water Pollution Control); and
(9) A.A.C. R18-14-101 through 115 (Water Quality Protection Fees).
(c) *Memorandum of Agreement (MOA).* The Memorandum of Agreement between the State of Arizona and the EPA, Region 9, signed by the EPA Regional Administrator on March 24, 2025.
(d) *Letter from Governor.* Letter from the Governor of Arizona to the Regional Administrator, EPA Region 9, signed on February 16, 2024.
(e) *Statement of legal authority.* Attorney General's Statement, signed by the Attorney General of Arizona on September 5, 2024.
(f) *Program Description.* The Program Description, “Arizona Department of Environmental Quality Underground Injection Control Program Description (40 CFR 145.23)”, and any other materials submitted as part of the application or amendment thereto.
**40 CFR Part 147**
3. Revise § 147.151 to read as follows:
§ 147.151
(a) *Contents.* The UIC program that applies to all injection activities on Indian lands in Arizona, except for Class II wells on Navajo Indian lands for which EPA has granted the Navajo Nation primacy for the SDWA Class II UIC program (as defined in § 147.3400), is administered by EPA. The UIC program for Navajo Indian lands, except for Class II wells on Navajo Indian lands for which EPA has granted the Navajo Nation primacy for the SDWA Class II UIC program, consists of the requirements contained in subpart HHH of this part. The program for all injection activity except that on Navajo Indian lands consists of the UIC program requirements of parts 124, 144, 146, and 148 of this title, and any additional requirements set forth in the remainder of this subpart. Injection well owners and operators, and EPA, shall comply with the requirements of this paragraph (a).
(b) *Effective dates.* The effective date for the UIC program on Indian lands in Arizona, except for the lands of the Navajo Indians, is June 25, 1984. The effective date for the UIC program on the lands of the Navajo, except for Class II wells on Navajo Indian lands for which EPA has granted the Navajo Nation primacy for the SDWA Class II UIC program (as defined in § 147.3400), is November 25, 1988.