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Water: Underground Injection Control

UIC Program Primacy

State UIC Programs have primary enforcement responsibility (or primacy) once their UIC programs have been approved by EPA. This page provides information about the requirements for obtaining primacy and which states have been granted this authority.


What is primacy?

The UIC Program requirements were developed by EPA and designed to be adopted by states, territories, and tribes. States, territories, and tribes can submit an application to EPA to obtain primary enforcement responsibility, or primacy. Agencies that have been granted this authority oversee the injection activities in their states. The requirements for primacy programs are outlined in the UIC regulations at 40 CFR Part 145.

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Is there more than one way for a state to apply for primacy?

Yes. States can apply for primacy in the following ways:

  • To gain authority over all classes of wells or Class I, III, IV, V, and VI state programs must be as stringent as the federal program and show that their regulations contain effective minimum requirements (e.g., inspection, monitoring, and recordkeeping requirements that well owners and operators must meet). State regulations must be as stringent as the federal requirements, but may be more stringent. Such states are authorized under section 1422 of the SDWA
  • To gain authority over Class II wells only, states with existing oil and gas programs may make an optional demonstration that their program is effective in protecting USDWs. Such states are authorized under section 1425 of the SDWA. Criteria for approval under §1425 are in Guidance for State Submissions Under Section 1425 of SDWA (PDF) (23 pp, 50K, about PDF).
  • To gain authority over Class VI wells only, states may apply for Class VI primacy under section 1422 of the SDWA for managing UIC GS projects under the Class VI Program.

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Who currently has primacy?

EPA has approved primacy programs for all well classes in 33 states and 3 territories; it shares responsibility with 7 states (i.e., EPA has authority over some classes and the state has authority for others); and EPA directly implements the Class VI Program nationally.

Map of United States of America showing states that have sole primacy over their Underground Injection Control (UIC) program. The map also shows states, tribes, and territories in the U.S. that share their primacy with EPA's UIC program. Currently only The Fort Peck (FP) Tribes and the Navajo Nation (NN) are the only Tribes with UIC Primacy.

Currently, two tribes have Class II primacy.

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What if a state, territory, or tribe does not get primacy?

If a state does not obtain primacy for all or some of the well classes, EPA implements the program directly through one of its Regional offices. Currently, EPA implements the program for all well classes in 10 states; and for Class VI wells in all states, tribes, and territories.

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