Primary Enforcement Authority for the Underground Injection Control Program
On this page:
- How primary enforcement authority is defined
- How states, territories, and tribes apply for primacy
- States, territories, and tribes with primacy
The UIC program requirements were developed by EPA. They are designed to be adopted by states, territories, and tribes.
Primary enforcement authority, often called primacy, refers to state, territory, or tribal responsibilities associated with implementing EPA approved UIC programs. A state, territory, or tribe with UIC primacy, or primary enforcement authority oversees the UIC program in that state, territory, or tribe.
Primacy programs are established under two sections of the Safe Drinking Water Act (SDWA).
Section 1422 requires primacy applicants meet EPA’s minimum requirements for UIC programs. Programs authorized under this section, referred to as 1422 programs, have primacy for Class I, II, III, IV, V, and VI wells. Under Section 1422, applicants may submit primacy applications for:
- All well classes
- Classes I – V
- Class VI
Section 1425 requires primacy applicants to demonstrate their standards are effective in preventing endangerment of USDWs. Section 1425 programs are not required to meet EPA’s minimum requirements as long as applicants can show their standards protect USDWs. Section 1425 applies to Class II wells only.
EPA may grant primacy for all or part of the UIC program. This means that in some jurisdictions primary enforcement authority for certain well classes may be shared with EPA.
States, territories, and tribes with primacy
Thirty four states and three territories have EPA approved primacy programs for well classes I, II, III, IV and V. Additionally, seven states and two tribes have applied for and received primacy approval for Class II wells only.
North Dakota is the only state with primary enforcement authority for UIC Class VI wells. EPA directly implements the Class VI program in all other states, territories, and tribes.
EPA directly implements the Class II program in ten states, three territories, the District of Columbia, and for all tribes except for the Navajo Nation and Fort Peck Tribes. Twenty four states and two tribes have UIC Class II primacy under SDWA Section 1425. Sixteen states and three territories have UIC Class II primacy under SDWA Section 1422.
On April 10, 2018, EPA issued a final rule approving North Dakota’s application for primary enforcement responsibility for Class VI Wells located within the state. EPA will continue to directly implement the Class VI program within Indian lands. North Dakota is the first state to receive primacy for Class VI UIC wells. Review information on North Dakota's UIC program revision package at Docket ID EPA-HQ-OW-2013-0280.
On July 30, 2018, EPA issued a final rule amending 40 CFR part 147, Subpart N, to reflect the voluntary transfer of Class II primacy from the state of Idaho to EPA. Idaho will retain primacy for Class I, III, IV, and V wells.
- Review the Federal Register Notice approving the voluntary transfer of Idaho’s Class II primacy to EPA .
EPA issued final approval, under the SDWA, granting the Commonwealth of Kentucky primary enforcement responsibility for UIC Class II injection wells located within the state. This action excludes Class II injection wells located on Indian lands. State of Kentucky Underground Injection Control (UIC) Class II Program; Primacy Approval Final Rule is effective March 21, 2017.
If a state, territory, or tribe 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 UIC program for all well classes in nine states and two territories. Except for the Navajo Nation and Fort Peck Class II programs, EPA directly implements the UIC program in Indian country.